INFORMATION AND CHARACTERISTICS.

Although the common and scientific name of this toothed cetacean refers to the white color of its snout, they may or may not have the beak of this color.

The white-beaked dolphin is the largest member of the genus Lagenorhynchus, and it was one of the first dolphins of this genus to be scientifically recognized, back in 1846.

Order: Cetacea
Family: Delphinidae
Genus: Lagenorhynchus

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

Morphology.
It has a sturdy body, a short and thick beak and a narrow tail. It has a big and sickle-shaped dorsal fin just in the middle of its body.

Weight and size.
Adult individuals measure between 2.3 and 3.1 meters in length and weigh 180 to 354 kilograms. Males are slightly larger than females.

Skin Coloration.
It has a black or dark gray dorsal area. The sides usually have lighter stripes with different shades of light gray almost white. Its beak may exhibit a whitish color, but it can also be gray and even black.

Distinctive characteristics.
It has a white patch that starts just behind the dorsal fin and ends before the tail flukes.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

The white-beaked dolphin inhabits the waters of the North Atlantic Ocean. In the western part of this ocean it dwells from the Strait of Davis to the south of Cape Cod (Massachusetts, United States) passing through the center and the west of Greenland; In the east of the ocean is distributed from Iceland to Portugal but in the north reaching as east as the Scandinavian peninsula. Its locations include the Barents Sea, the Baltic Sea, Ireland, Canada, the Irish Sea and the United Kingdom. It also resides in the west of the Mediterranean Sea.

It inhabits the cold subpolar waters of its distribution zone, in the continental shelf, along with the edge of this and in coastal waters; Mainly in waters whose depth does not exceed 200 meters.

WHAT DO THEY EAT? DIET AND EATING HABITS.

It feeds on a large variety of mesopelagic fish mainly those that group in schools, like the capelin, haddock, hake, herring and cod. It also consumes crustaceans and cephalopods (octopus and squid), like most dolphins.

This species performs hunting techniques cooperatively on the surface of the ocean. It sometimes associates with humpback whales (Megaptera novaeangliae), Fin whales (Balaenoptera physalus) and other dolphins, including those of the species Tursiops truncatus (bottlenose dolphin).

HOW DO THEY BEHAVE? BEHAVIOR

The White-beaked dolphins create social groups composed of 5 to 50 individuals (generally less than 30), but they occasionally form larger groups of up to 1,500 dolphins. There is little information on the social structure of this species, but the separation by age and sex can occur. They sometimes mix and associate with large species like fin whales and humpback whales, and other small cetaceans, especially in the feeding areas (Reeves et al. 2002). These gregarious dolphins often perform acrobatic jumps on the surface and frequently approach ships to ride the bow waves.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

The white-beaked dolphin reaches sexual maturity when it is between 7 and 13 years old or when they grow to a length of 2.4-2.5 meters. The gestation period lasts about 11 or 12 months. Subsequently, a single offspring is born in the summer (months of May to September) measuring about 1.1-1.2 meters long.

Additional information on the reproduction of this species is so far unknown.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation Status: “Least Concern.”

This species has been and still is hunted in the waters of the Faroe Islands, Iceland, Norway and Greenland, and even in Canada off the coast of Newfoundland, to obtain its oil and meat. Also, they are affected by the contamination of their habitats with heavy metals and organochlorines.

It is under protection by the ASCOBANS (Agreement on the Conservation of Small Cetaceans in the Baltic, North East Atlantic, Irish and North Seas) and in the Red List of the International Union for the Conservation of Nature, it appears as a species with a conservation status of “Least Concern.”

References

Jefferson, Webber, Pitman. Marine Mammals of the World: A Comprehensive Guide to Their Identification. Academic Press, 2015. Page 282.

William F. Perrin, Bernd Würsig, J.G.M. ‘Hans’ Thewissen. Encyclopedia of Marine Mammals. Academic Press, 2009. Page 1255.

http://www.cms.int/reports/small_cetaceans/data/l_albirostris/l_albirostris.htm

http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/whitebeakeddolphin.htm

Sotalia fluviatilis

INFORMATION AND CHARACTERISTICS.

The unique name of this cetacean is pronounced “tucushi” and comes from the Tupi language, typical of South America. It is also known as gray bufeo and black bufeo in the area.

This little-known species is physically similar to the bottlenose dolphin (Tursiops truncatus) except for its size and other minor details. It is found in fresh and salty waters but is not genetically related to the South American river dolphins. Described initially in 1853, the Tucuxi is a small dolphin.

Order: Cetacea
Family: Delphinidae
Genus: Sotalia

The author of the image: Archilider.

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

Morphology.
The shape of its body is similar to that of the bottlenose dolphin as it is fusiform and slightly robust. It has a triangular dorsal fin slightly hooked. Its snout is long, very pronounced and narrow. Its pectoral flippers are large.

Weight and size.
It is one of the smallest cetaceans of the Delphinidae family, and there is no presence of sexual dimorphism. Adults have an average length of 2.1-2.2 meters and a weight of 35 to 55 kilograms. Individuals living in freshwater have a shorter length, estimated at 1.5 meters.

Skin Coloration.
The color of its dorsal skin varies being either bluish, gray or dark brown. The lower part of its body is white, light gray or pink and the sides are a shade between the dorsal and ventral colors. It has a dark strip blended between the snout and each of the pectoral flippers. Some populations have yellow stripes on the sides and a clear spot on the dorsal fin.

Distinctive characteristics.
Most specimens have a white patch on the tip of the snout.
There are two ecotypes of this species, one living in ocean waters of the Atlantic Ocean and another dwelling in the Amazon and Orinoco Rivers.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

The Tucuxi is a species endemic to South American waters; the tucuxi inhabits waters of Brazil, Panama, Peru, Ecuador, Colombia, Nicaragua, Venezuela and probably Honduras. Its distribution range starts from this last country or Panama and runs along the east South American coasts ending in southern Brazil.

There are two ecotypes of this species, one living in the waters of the Atlantic Ocean and other that dwells in the Amazon and Orinoco rivers. Those who live in the ocean stay near the coasts, in estuaries, and bays. The freshwater ecotype, inhabit the channels of the rivers mentioned above reaching upriver up to 2,500 kilometers in the Amazon and 250 kilometers in the Orinoco.

WHAT DO THEY EAT? DIET AND EATING HABITS.

The tucuxi is a carnivorous dolphin. It submerges for about 30 seconds to search for food, and they frequent the confluence areas because it is a zone suitable for the development of species such as plankton which in turn attracts many species of fish. Therefore, this dolphin usually goes to the confluences of bodies of water, but it also goes to places near the coasts.

Ray-finned fishes (Actinopterygii class), octopuses, squids, and shrimps are the main part of its diet. If they are in the open ocean, they prefer to feed on small fishes grouped in schools, and near the coasts, they prefer to catch pelagic or demersal fishes and cephalopods.

The tucuxi living in the Amazon consume around 28 species of fish, and within this set, they prefer those that belong to the family Curimatidae, because they represent 52 percent of their total diet.

HOW DO THEY BEHAVE? BEHAVIOR

It is considered a shy dolphin which never get close to boats or people and whose swimming is slow, but this does not mean that is “not active.” On the contrary, it spends most of the day doing activities, and its leaps out of the water are impressive. It can leap up to 1 meter out of the water and executes jumps, tumbles and blows with its pectoral flippers and the tail either alone or in coordination with other members of its pod. The only thing they do not do is riding the bow waves of boats, which is evident, as they do not come close to them.

This dolphin has a social structure based on small groups containing 2 to 6 members. In most cases, the pod is made up of 9-20 individuals for the ecotype living in freshwater and up to 50 members for those dwelling in the coastal waters of the Atlantic. Occasionally the pods associate with other species of dolphins, such as the Amazon pink dolphin (Inia geoffrensis). In any case, it seems that the adult males dominate the pods and they are the ones followed by other members.

The flood season is perfect for swimming through small tributaries, but they do not dare to leave the main river channels and enter into flooded forests. On the other hand, they communicate through whistles and clicks. Their sounds are higher than those of other dolphins, and they produce them while feeding, perhaps to call their peers.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

Researchers believe that the females of this species mate with several males in the same breeding period (polyandry). The courtship includes an aggressive behavior of males.

Both genders reach sexual maturity at six years of age. The gestation period lasts between ten and twelve months, and the calf is born at some point in the autumn. The offspring can have a length from 71 to 106 centimeters.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation status: Data Deficient.

The tucuxi has a conservation status of “Data Deficient” in the Red List of the International Union for the Conservation of Nature (IUCN). The size of the total population is unknown, but it is true that it is vulnerable to the effects of human activities such as:

– Bycatch.
– Direct hunting.
– Prey Overfishing.
– Habitat Contamination.
– Acoustic pollution.
– Boat collisions.
– Construction of dams that reduce and segment their distribution.

This dolphin is in Appendix II of the CMS (Convention on Migratory Species) for animals in need of conservation agreements and in Appendix I of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), which contains species with a higher danger of extinction and whose trade is prohibited. Also, the International Whaling Commission (IWC) initiated a plan called Project Sotalia with the aim of studying this species thoroughly.

References

http://www.iucnredlist.org/details/190871/0

William F. Perrin, Bernd Würsig, J.G.M. ‘Hans’ Thewissen. Encyclopedia of Marine Mammals. Academic Press, 2009. Page 1188.

http://animaldiversity.org/accounts/Sotalia_fluviatilis/

http://www.arkive.org/tucuxi-dolphin/sotalia-fluviatilis/

INFORMATION AND CHARACTERISTICS.

This dolphin is one of two species of the genus Lissodelphis. It is a toothed cetacean found only in the southern hemisphere. Bernard Germain de LacépèdeIt described this species in 1804 based on a specimen he saw near the island of Tasmania.

PHYSICAL DESCRIPTION.

Morphology.
This dolphin has the thinnest body of all cetaceans. Its body, incredibly hydrodynamic, is similar to the one of the northern right whale dolphin (Lissodelphis borealis) with a slender shape, a short snout and lacking the dorsal fin. It has a tilted forehead instead of rounded like most species and pectoral flippers with a sickle shape.

Weight and size.
The adult dolphin measures 1.8-2.9 meters in length and weighs between 60 and 100 kilograms. The sexual dimorphism is very slight, being the male bigger than the female.

Order: Cetacea
Family: Delphinidae
Genus: Lissodelphis

Skin Coloration.
The body of this cetacean is bicolor. The dorsal area is black from the forehead to the tail lobes. The white color starts from the snout and continues to the belly and up to the middle of both sides. The pectoral flippers are usually gray, and some individuals exhibit small white patches on the head.

Distinctive characteristics.
Their coloring pattern and the lack of dorsal fin are the main distinguishing features. There may be confusion with the northern right whale dolphin because they have a similar appearance, but the difference between them lies in the fact that the sides of this dolphin are entirely black, and the snout is not white as the southern species. Besides, the distribution area of each species is far from each other.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

It has a circumpolar distribution only in waters of the southern hemisphere, between the Antarctic Convergence and the Subtropical Convergence. Its limits are between latitudes 30° south and 65° south, being the north of Peru the northmost limit of its distribution.

It is present in countries such as Australia, Chile, Argentina, New Zealand, Uruguay, South Africa, Mozambique, and Peru.

It is a pelagic dolphin that prefers high seas and only approaches the coasts if the waters are deep on the edge of the continental shelf. The temperatures of their cold habitats range between 1° and 20° Celsius degrees.

WHAT DO THEY EAT? DIET AND EATING HABITS.

Studies of the stomach of specimens of this species report a carnivorous diet in which mesopelagic fish, crustaceans, and cephalopods have preponderance. Their preys commonly inhabit depths between 200 and 1,000 meters.

Given its thin and hydrodynamic body, most scientists think that this dolphin is quick and agile to capture its prey, but if it feeds on the surface or in lower layers of the water column, it is still unknown.

Some of its favorite prey are lanternfish (Myctophidae), bigeye tuna (Thunnus obesus), squid, shrimp and species of the family Euphausiacea, which includes several species of krill.

HOW DO THEY BEHAVE? BEHAVIOR

It is a highly gregarious species which the creation of pods influence its social and individual behavior. A pod of Lissodephis peronii is usually composed of more than 100 members and may have up to 1,000 members. However, the average number of dolphins in a group is around two hundred.

If a dolphin is alone without company, it shows a relative shyness and avoids the ships. On the other hand, if a dolphin is with its pod, it shows more activity and dynamism. They can jump and hit the water with their belly or tail and create disturbances on the surface of the ocean due to the massive number of individuals in the pods.

Pods usually submerge for more than 6 minutes, but a single dolphin only dives for a very short time, so it tends to surface every 10 seconds or so. When swimming slowly, it only keeps the spiracle and part of the head out of the water; this is usually done while resting or during periods of low activity.

To date, there is no significant data on the existence of migration patterns, although it is likely that during the spring and summer they move northwards.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

There is a lack of information about most of the breeding habits of the southern right whale dolphin, but research suggests that males reach sexual maturity when they have a length of 2.51 meters and females are sexually mature with an approximate length of 2.18-2.28 meters.

The birth season is not known although in winter and spring more calves are seen, so perhaps the births occur around those seasons.

A calf can measure 0.86 meters in length and weigh about 5 kilograms at birth. Its longevity is approximately 42 years in the wild.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation Status: Data Deficient.

It is true that there are more doubts than confirmed facts about this species. In fact, not even the International Union for Conservation of Nature (IUCN) has sufficient data to assess its conservation status which has a “Data deficient” classification due to the lack of information about the species.

However, this does not mean that the southern right whale dolphin is out of danger as this species has several threats, most of them derived from human activities. In Peru and Chile they have been caught for consumption, and in other regions, bycatch is common when these cetaceans become entangled in gillnets, particularly those trying to catch swordfish.

There are no specific conservation efforts for the Southern right whale Dolphin yet, but CITES has included it in Appendix II of endangered species where this organization lists the animals whose commercial trade must follow strict regulations.

References

Jefferson, Webber, Pitman. Marine Mammals of the World: A Comprehensive Guide to Their Identification. Academic Press, 2015. Page 306.

http://www.iucnredlist.org/details/12126/0

http://www.cms.int/reports/small_cetaceans/data/L_peronii/l_perronii.htm

http://www.fao.org/fishery/species/18218/en

INFORMATION AND CHARACTERISTICS.

Delphinus delphis is probably one of the most common species of dolphin, and it has a broad distribution around the world. The naturalist Carlos Linnaeus was the first person to describe this short-beaked cetacean in 1758. It is probably the most abundant dolphin on the ocean.

Order: Cetacea
Family: Delphinidae
Genre: Delphinus

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

It is a medium-sized dolphin, similar to other common dolphin species.

Weight and size.
The sexual dimorphism is slight since males are larger and heavier than females. The average length is 1.52-1.82 meters, and the weight is 100-136 kilograms.

Morphology.
Its fusiform body has a long snout (even though is shorter than that of the Delphinus capensis) and a rounded melon. The Short-beaked common dolphin has a dorsal fin almost triangular, with a curved inclination. The pectoral flippers and the flukes of their caudal fin are small.

Skin Coloration.
Its coloring pattern features a dark dorsal area and a white ventral region. From the end of the beak starts a layer of dark color that extends toward the dorsal fin and the sides, forming a “V.” From the lower jaw to the flippers, there is a narrow black stripe, and a dark patch is around the eyes. Along the sides, there is a thick band of light color that does not become white.

Distinctive characteristics.
The shape of the coloring pattern is its most distinctive sign. To distinguish it from Delphinus capensis, which is very similar, the size of the beak is the main feature that makes them different.

> Short-beaked common dolphin characteristics.
> Short-beaked common dolphin – Delphinus delphis.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

This dolphin inhabits all tropical, subtropical and warm seas of the world, especially in the Pacific and Atlantic oceans. In the south of Australia. In the western Atlantic it extends from Newfoundland to Florida in the United States; From Norway to West Africa in the eastern Atlantic, from Canada to Chile in the eastern Pacific Ocean; In the central region of this ocean and around New Caledonia, New Zealand and Tasmania. It has a presence in a few closed seas: the Sea of ​​Japan, the Sea of ​​Ojotsk (Asia) and the Black Sea.

It inhabits coastal areas or the high sea as long as the water temperature is 10 to 28° Celsius. It dwells along the continental slope, in waters with depths ranging from 200 to 2,000 meters and has a preference for the marine areas where the upwelling occurs and for the seamounts and escarpments.

WHAT DO THEY EAT? DIET AND EATING HABITS.

Small fish such as herring, sardines, hake, and anchovy are an important part of their diet, also cephalopods which include octopus and squid. They consume crustaceans to a lesser extent. In total, an adult dolphin consumes more than 8 kilograms of food per day.

It feeds mostly at night, and it has cooperative hunting strategies. When a group of dolphins is looking for food, each member submerges for up to 8 minutes to detect prey. If they are successful and find a school of fish or any other prey, they can perform two hunting strategies:

1.- Individually, these dolphins approach the center of the school of fish and chase them. Before the prey escapes, they catch it.

2.- Dolphins dive towards a school of fish chasing them to guide them towards the surface of the water. They prefer to feed at night because they wait for the prey that migrates to the surface every night.

The whole hunting process takes about 1 hour, and they can submerge up to 200 meters deep during the process.

HOW DO THEY BEHAVE? BEHAVIOR

It is very rare to find a Short-beaked common dolphin alone. These dolphins are very social which can be seen in all their daily activities like eating, traveling and even breathing. The pods are very numerous and are composed of 10 to 500 individuals but, as in other species, they usually associate with other pods forming large temporal groups of thousands of dolphins. Its association with other species of cetaceans like the pilot whales (Genus Globicephala) is also common.

This species is a perfect example of a playful dolphin. It jumps, hits the water with its flippers, and spin in the air for several hours. Without a doubt, their favorite game is to ride the bow waves of boats. Its swimming speed reaches up to 60 kilometers per hour.

Short-beaked common dolphin – Delphinus delphis.

It shows great empathy for its peers. When a member of the pod is sick or injured, another dolphin helps him to float and breathe, a fact that demonstrates their capacity for bonding. This dolphin can remember its mates even though it has been a long time since they separated and experiences joy and excitement. In the same way, if one dies or separates, it shows sadness.

Individuals in some regions migrate seasonally in a process induced by the temperature increase of the surface water.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

An unusual fact about the reproduction of this dolphin is that, although it is usual to have only one offspring, there are some cases of births with 2 and up to 3 dolphins, when in other species this happens much less frequently.

Males reach sexual maturity between 12 and 15 years of age, but females are mature when they reach 85 percent of their final size and if they have ovulated at least once in their lifetime. But the sexual maturity and the interval of births vary considerably among populations since in some parts these dolphins reach maturity at 2.7 years; In the eastern Pacific Ocean females give birth every three years, but in the Black Sea they can do it every year.

Their sexual habits are not only for reproduction. They can participate in activities that provide pleasure for themselves or their peers. During spring and autumn, males begin to courtship females with actions involving physical contact and approach, then both mate. Females have a gestation period of 10-12 months.

From the moment of its birth, the offspring is of vital importance for the mother and the pod; It swims next to its mother and separates just a few feet from it as it grows. Weaning occurs when offspring are between 5 and 19 months of age.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation Status: “Least Concern.”

By-catch with longlines, gillnets, and trawls constitutes the greatest threat to the survival of this species. In Asia and areas of the Mediterranean Sea, is hunted for human consumption to prepare some little-known dishes, but also for its oil. Additionally, the chemical contamination and the human disturbance of their habitat are also important factors, although fortunately the species still has a conservation status of “Least Concern” on the Red List of the International Union for Conservation of Nature.

The species has the safeguard of the Marine Mammal Protection Act of 1972. In the United Kingdom, killing cetaceans is banned by the law. Seven European countries signed the Agreement on the Conservation of Small Cetaceans in the Baltic, North East Atlantic, Irish and North Seas (ASCOBANS). Also, there are plans to create protected areas for this dolphin and to control the pollution of its habitat.

References

William F. Perrin, Bernd Würsig, J.G.M. ‘Hans’ Thewissen. Encyclopedia of Marine Mammals. Academic Press, 2009. Page 255.

Mammals in the Seas: Small cetaceans, seals, sirenians and otters. Food & Agriculture Org., 1978.

http://www.cms.int/reports/small_cetaceans/data/d_delphis/d_delphis.htm

http://www.iucnredlist.org/details/6336/0

Feresa attenuata

INFORMATION AND CHARACTERISTICS.

The pygmy killer whale despite its name, is not closely related to the orca (Orcinus orca), the so-called “killer whale,” but it has similar features which gave it this name. The naturalist John Gray described this species in 1874, but previously in 1827, the report of another scientist included it. Despite these works, scientists did not take much notice of this dolphin, which remained almost unknown for many years.

This situation changed in 1954 when a Japanese cetacean scientist Munesato Yamada published his observations based on parts of the body of a specimen. This researcher also proposed the name “pygmy killer whale” for the species.

Order: Cetacea
Family: Delphinidae
Genus: Feresa

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

Morphology.
The pygmy killer whale has a thin body, a rounded head, and a narrow tail. It lacks the long snout that many people associate with dolphins. Its dorsal fin is high and curved at the tip just like its pectoral flippers. The lower jaw has 20-26 teeth while the upper jaw has only 16-24.

Weight and size.
Adults have a length of 2.1-2.6 meters and weigh about 170-225 kilograms.

Skin Coloration.
Its dorsal skin is dark gray, the ventral region is white, and on the sides the black blend with a light gray layer. Its lips are white.

Distinctive characteristics.
The curvature of its dorsal fin, its gray skin, white lips and the lack of a pronounced snout are the features that make the pygmy killer whale different from other species.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

The distribution of the pygmy killer whale includes the tropical and subtropical waters of the Pacific Ocean, Atlantic Ocean and the Indian Ocean between latitudes 40° north and 35° south. Encounters with this species are extremely rare and are less than 1 percent of the total sightings of toothed cetaceans. Nevertheless, there are more sightings in the eastern tropical Pacific and the southern Atlantic Ocean than everywhere else.

To the north, it reaches the latitude of the Bay of Biscay, and to the south, it reaches the tip of the African continent.

It likes to inhabit waters with up to 500 meters deep with warm temperatures above 18° Celsius. It rarely approaches the coasts, and when it does, usually approximates volcanic islands.

WHAT DO THEY EAT? DIET AND EATING HABITS.

According to remains found in the stomachs of some specimens of pygmy orcas, it is a carnivorous and predatory dolphin that feeds on several species of fish, cephalopods and even small cetaceans. Its main foods are octopus, squid (Families Onychoteuthidae and Ommastrephidae), sardines (Family Clupeidae) when it remains in captivity.

It probably looks for food at night and consumes slightly large prey for its size because its teeth are also relatively large.

HOW DO THEY BEHAVE? BEHAVIOR.

Like many other dolphins, it is a species that likes playing. It frequently jumps out of the water, strikes its pectoral flippers against the water, pulls its body out of the water and even hit the surface of the ocean with the head. However, it is perhaps a dolphin less active than other dolphins since it has been seen resting on the surface in the company of other pygmy killer whales, all forming a group swimming in the same direction.

It is a highly social species that creates small groups. The pods have about 12-50 members but occasionally form groups of hundreds of individuals. It is a species very aggressive when kept in captivity.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

There isn’t much information about the reproduction of the pygmy killer whale. The researchers think that they reach sexual maturity according to its length, that is, when males reach more than 2.16 meters and when females exceed 2.21 meters. In other regions, this cetacean reach maturity with a length of 2.31 meters, however, the age at which this occurs is entirely unknown.

The other known data on the reproduction of the pygmy killer whale is about the birth of the single offspring. The length of the calf is around 0.8 meters, but more studies and observations are needed to support this data and get conclusive information.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Condition: “Data defficient”.

As expected for a little known and understudied species, the Red List of the International Union for the Conservation of Nature classifies the Pygmy killer whale as “Data deficient.”

However, it is a species highly vulnerable to loud noises and perhaps to climate change. In Indonesia, Japan, Sri Lanka and areas of the Caribbean, it is the subject of direct fishing for human consumption of meat and oil. Particularly in Sri Lanka, fishers use parts of its body as bait for sharks and other species of fish.

In specimens off the coast of Florida, United States, scientists found traces of hydrocarbons in their body tissues as the result of water pollution that affects the cetacean.

At present, there are no specific strategies focused on the conservation of the pygmy killer whales. However, it is in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), in other words, it is a species that Although not in great danger of extinction, its trade must be strictly regulated.

References

http://www.iucnredlist.org/details/8551/0

http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/pygmykillerwhale.htm

William F. Perrin, Bernd Würsig, J.G.M. ‘Hans’ Thewissen. Encyclopedia of Marine Mammals. Academic Press, 2009. Page 938.

http://www.fao.org/fishery/species/18192/en

Lagenorhynchus australis

INFORMATION AND CHARACTERISTICS.

The Peale’s dolphin or Black-chinned Dolphin are the common names used to call this toothed cetacean of the southern hemisphere. In English, its common name, Peale’s dolphin is in honor to the naturalist Titian Peale, who described the species in the year 1848.

It is the largest species of the genus Lagenorhynchus, although in recent years a closer relationship with the genus Cephalorhynchus was discovered, which could end in a new taxonomic classification for this species shortly.

Order: Cetacea
Family: Delphinidae
Genus: Lagenorhynchus

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

Morphology.
It is perhaps the most robust species of its genus but still conserves a body with a form of a torpedo. Its dorsal fin, pointed and curved, can reach up to 50 centimeters of height and its rounded pectoral flippers measure around 30 centimeters in length. It has a short beak; it is only about 5 cm long.

Weight and size.
There is a slight sexual dimorphism that produces greater dimensions in the case of males. An adult measures 2.18-2.20 meters in length while the females reach about 2.10 meters in length. The maximum size of an adult is 3.10 meters. They weight on average 115 kilograms.

Skin Coloration.
The color of its skin is remarkable and very striking. Black on the dorsum and white on the belly, this two-color pattern is interrupted by a thin white stripe that begins below the dorsal fin and widens as it extends backward. From the eyes to the middle of the sides there is a white area separated from the belly by a thin black band. The pectoral flippers and the dorsal fin are black.

Distinctive characteristics.
It is true that this species can easily be confused with the Dusky dolphin (Lagenorhynchus obscurus), but this dolphin has a dark face and a thin black band near the rib cage which makes it different.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

This animal is endemic of the southern hemisphere, and they dwell between latitudes 30° south in the Pacific and 38° south in the Atlantic Ocean and 60° south where both oceans join, that is, in South American waters surrounding the southern tip of the continent. This distribution includes only Chile, Argentina, and the Falkland Islands; Around Tierra del Fuego, Cape Horn and the Strait of Magellan. Recently sightings of the species were reported near the Cook Islands, between Hawaii and New Zealand but this is unconfirmed data yet.

It is a coastal dolphin that inhabits seas with very shallow depths on the continental shelf. It dwells in the bays, inlets, canals, fjords and stay around the islands, on beds of seaweed and even on the sandbanks.

WHAT DO THEY EAT? DIET AND EATING HABITS.

The Peale’s dolphin does not mind feeding alone but usually hunts in groups. It has a carnivorous diet and eats large quantities of fish as well as crustaceans and cephalopods. The prey most consumed by this species are:

– Argentine red shrimp (Pleoticus muelleri).
– Squids of the species Loligo gahi and Illex argentinus.
– Argentine Hake (Merluccius hubbsi).
– Tadpole codling (Salilota australis).
– Patagonian grenadier (Macruronus magellanicus).
– Southern red octopus (Enteroctopus megalocyathus).
– Anchovy (Family Engraulidae).
– Herring (Genus Clupea).

It has a very varied diet. The feeding process begins with the formation of groups of 5 to 30 individuals who stay underwater for 10 seconds-1.5 minutes. They have a marked preference for searching algae beds. When they find prey, they surround it and begin to eat. If the victims are a school of fish, they spend time chasing, corraling and eating them in organized turns.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

The information about their reproductive habits is very scarce. What is known is that the female has one offspring per delivery and gives birth during the spring to autumn after a gestation period of 10 to 12 months.

When births are close, the mothers approach to areas close to the coast. There a calf is born with a length of approximately 0.9-1.25 meters, which swims next to its mother as soon as it leaves the belly. The offspring is cared for about 18 months or until it is two years old.

HOW DO THEY BEHAVE? BEHAVIOR

The pods of Peale’s dolphins have few members, between 2 and 20 individuals although there are groups as small as 2-4 or as large as 100 dolphins. These large groups, if created, are in turn segmented into smaller social clusters. They usually hunt by cooperation, but a hypothesis assumes that this happens only when there is abundant food.

They occasionally associate with other species of dolphins, especially the Commerson’s dolphin (Cephalorhynchus commersonii) and the Risso’s dolphin (Grampus griseus).

It is a shy dolphin that sometimes comes close to the boats but not often. From there you can see it jumping, riding the bow waves and splashing water with its tail.

No migration patterns are known, but southernmost individuals are believed to follow fish movements.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation Status: “Data Deficient.”

The Red List of the International Union for the Conservation of Nature does not have sufficient data to assess this species according to its state of conservation. However, since the 1970s it has been exploited to use parts of its body as bait for crabs and is not free of the danger that gillnets mean.

In addition to direct and incidental catch, contamination of their habitat with organochlorines endangers their health, as well as tourist rides that offer dolphin observations can disrupt their life underwater.

The Peale’s dolphin is in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), where the species whose trade requires strict regulation appear. Also, the Chilean government has implemented measures to reduce the use of dolphin meat as a crab bait, and because of this, it seems that the number of catches for this purpose has reduced.

References

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.452.3889&rep=rep1&type=pdf

http://www.iucnredlist.org/details/11143/0

https://en.wikipedia.org/wiki/Peale%27s_dolphin

http://www.cms.int/reports/small_cetaceans/data/L_australis/L_australis.htm

http://www.arkive.org/peales-dolphin/lagenorhynchus-australis/

INFORMATION AND CHARACTERISTICS.

The Northern right whale dolphin and its close relative the southern right whale dolphin (Lissodelphis peronii), are the only dolphin species of the family Lissodelphis that lack a dorsal fin. The naturalist Titian Peale was the first to describe this species in 1848. Its scientific name comes from word Lissos that means “soft” in Greek, and the Latin borealis which means “north.”

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

Morphology.
The slender, hydrodynamic body of the northern right whale dolphin allows it to reach great speed when swimming. Both species of the genus Lissodelphis are the thinnest of all the small cetaceans, and this, in particular, is endowed with a short “snout” and a tilted forehead, both separated by a fold. It has no dorsal fin but has two small, curved and pointed pectoral flippers.

Order: Cetacea
Family: Delphinidae
Genus: Lissodelphis

Weight and size.
Usually, males are larger and heavier than females. An adult male individual measures approximately 3.1 meters in length but the range of the female is 2.3-2.6 meters. The weight oscillates between 60 and 100 kilograms.

Skin Coloration.
The shining dolphin’s skin has a dark color on the dorsal area that contrasts with the white belly, however, this is little visible. Under the lower jaw, it has a white spot. Both the pectoral flippers and the caudal fin are black.

Distinctive characteristics.
It is easy to distinguish this dolphin from other species, but it can be confused with sea lions because of the lack of dorsal fin. It is necessary to observe the dorsum and the coloring pattern characterized by black and white to avoid confusion with other animals.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

The Northern right whale dolphin has a limited distribution. It is found only in temperate and cold waters of the North Pacific Ocean between latitudes 30° and 50° north. They inhabit from northern Baja California in Mexico to the Gulf of Alaska, and in the west from Kamchatka in Russia to Japan. It is present in Russia, Mexico, the United States, Canada, and Japan.

It inhabits waters of the platform and the continental slope of great depth as well as (occasionally) areas near the coasts as long as they are deep. The temperature of its habitat is generally below 19° C but can tolerate those equal to or less than 24° C.

WHAT DO THEY EAT? DIET AND EATING HABITS.

Fish and cephalopods make up most of the diet of this carnivorous dolphin. It feeds on a wide variety of species. Some of its favorite prey are:

– Lanternfish (myctophids).
– Hake.
– Saury (family Scomberesocidae).
– Octopus.
– Squid.

When they inhabit around the center of the Pacific Ocean, the lanternfish make up the prey most consumed by this dolphin.

HOW DO THEY BEHAVE? BEHAVIOR.

The Northern right whale dolphin is very gregarious and creates pods quite large. They are comprised of 100-200 dolphins although the most common number is 200. However, sometimes they form superpods up to 2,000-3,000 individuals. The organization of such pods is somehow similar to some birds; they can travel forming a V.

It often associates with other dolphins and marine mammals, especially the Pacific white-sided dolphin (Lagenorhynchus obliquidens) and the Risso dolphin (Grampus griseus). It swims very fast, and its average speed is about 25 kilometers per hour, but it has speed bursts up to 40 kilometers per hour.

Sometimes the pod creates disturbance in the surface of the water due to its acrobatics, jumps, splashes with the tail and belly. It is also a little nervous and if something disturbs it, then flees immediately.

There are reports of seasonal migrations triggered by changes in water temperature. During spring and summer, the southernmost individuals travel to the north, and the northern ones migrate south.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

Data on the reproductive habits of this cetacean are very scarce. They reach sexual maturity between 9.7 and 9.9 years of age, being the later in males. In the winter-early spring period, there is more birth frequency, but other researchers believe that most births occur during the summer months, between July and August.

The female gives birth every 2 or more years to one offspring whose length is 0.8-1 meter.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation Status: “Least Concern.”

The conservation state of this dolphin is “Least Concern” on the Red List of the International Union for the Conservation of Nature (IUCN). A few years ago thousands of Northern right whale dolphins (Lissodelphis borealis) were killed annually in waters of Japan, Korea, and Taiwan as result of bycatch. Today, the number of deaths has reduced, but gillnets, direct harpoon hunting and contamination of its habitat still threaten the survival of this dolphin.

Efforts to preserve this dolphin involve its inclusion in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) and taking the measures recommended by the Pacific Offshore Cetacean Take Reduction Team of the National Marine Fisheries Service (NMFS) to reduce incidental fishing mortality.

References

Annalisa Berta. Whales, Dolphins, and Porpoises: A Natural History and Species Guide. University of Chicago Press, 2015.

http://www.iucnredlist.org/details/12125/0

http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/northernrightwhaledolphin.htm

INFORMATION AND CHARACTERISTICS.

Interesting name, isn’t it? This curious-looking dolphin is very little known as it inhabits deep waters away from the coasts. It is a close relative of the pygmy killer whale (Feresa attenuata) and the Pilot whales (Genus Globicephala), a fact that is evident just by looking at its physical appearance. It is also known as the melon whale, electra dolphin, and many-toothed blackfish.

John Edward Gray described it in 1846 and gave it the scientific name Lagenorhynchus electra. Its binomial name changed recently adding the word Peponocephala.

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

The melon-headed whale looks very similar to the pygmy killer whale, so it is important to know the external features of this species to differentiate both dolphins.

Morphology.
It has a thin, elongated torpedo-shaped body, but stylized. The head is conical and with a rounded melon. Its head lacks a snout, but instead, it is curved at the top and pointed at the front. However females, and young individuals sometimes develop a small but undefined snout.

It has long pectoral flippers that correspond up to 20 percent of the total length of its body, with a curved and pointed shape. For its part, the dorsal fin is curved and has a sickle shape. It features a long tail at the end of its body; Some mature males may develop a keel in the belly.

Order: Cetacea
Family: Delphinidae
Genus: Peponocephala

Weight and size.
Males and females have similar size, but the latter can grow a few more centimeters. Thus, the length of adults is about 3 meters. The weight of both genders reaches up to 200 kilograms.

Skin Coloration.
It has a dark gray or charcoal black skin color with a darker part extended under the dorsal fin. A white spot borders the urogenital zone, the same color that surrounds the lips. In contrast, the eyes have black spots on them that resemble a mask on the face.

Distinctive characteristics.
Seen from above, the melon-headed whale has the head more triangular than its relatives, and it also lacks the saddle-like dorsal spots like the others.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

It dwells in tropical and subtropical waters of the Atlantic Ocean, Pacific Ocean, and the Indian Ocean. Its habitat ranges from latitude 40° north to 35° south and includes the Gulf of Mexico, the Bay of Bengal, the South China Sea, the Arabian Sea and the Timor Sea.

Its presence is common in the United States, Australia, Mexico, Singapore, Solomon Islands, Tanzania, Bahamas, Belize, Iran, Peru, Puerto Rico, Taiwan, Cuba, Equatorial Guinea, the Philippines, Papua New Guinea and Japan, among other countries.

It inhabits areas of considerable depth on the continental shelf and around oceanic islands, in waters with temperatures above 25° C.

WHAT DO THEY EAT? DIET AND EATING HABITS.

The melon-headed whale regularly eats small fish and cephalopods, especially squid. From time to time it also adds crustaceans to its carnivorous diet.

It looks for its preys in waters of moderate depth. A conventional method to hunt is:
1) Detect a potential prey,
2) Chase it and guide it to the surface and
3) Capture it on the surface of the water and then eat it.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

The species has a sexual maturity late in life since males reach maturity at 15-16.5 years and females at 11.5 years old, this is when they reach about 2.34-2.45 meters in length.

The gestation period lasts around 12 months, and females have only one offspring. There is not reliable information about other breeding information of this species, such as a possible season for mating and birth. However, researchers noted that in high latitudes most births occur in July and August while in Low latitudes they occur during the spring months.

The females give birth every 2 or 3 years and the calves born weighing 10-15 kilograms.

HOW DO THEY BEHAVE? BEHAVIOR

The melon-headed whale is sociable by nature. Their pods are very numerous made up of 100-500 individuals, although some of them include up to 2000 dolphins. The links between members of the pods are very close, and cooperation is common to catch prey. They sometimes associate with other cetacean species such as Fraser’s dolphins (Lagenodelphis hosei), spinner dolphins (Stenella longirostris), Atlantic spotted dolphins (Stenella frontalis) and Short-finned pilot whales (Globicephala macrorhynchus).

The dolphins in the pod travel very close to each other and can form smaller groups within the same pod. In some regions (Australia, Brazil, Seychelles, Japan, Costa Rica, among others) frequently a significant number of them become stranded, a fact that can demonstrate the degree of social connection and therefore, segregation.

The melon-headed whale is fast when swimming individually, but the pod has a smaller speed, and they can move keeping the head out of the water. Their acrobatics are not famous, but those living at low latitudes can jump out of the water more frequently.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation status: “Minor Concern.”

The Melon-headed whale has a conservation status of “Minor Concern” on the red list of the International Union for the Conservation of Nature. Despite this, its survival is threatened by three main dangers:

Bycatch.
Many purse seines and gillnets trap many melon-headed whales in the eastern Pacific Ocean.

Hunting.
The numbers are not conclusive, but sometimes these dolphins are intentionally caught, some of them to take to water parks.

Pollution and degradation of their habitat.
Their habitat is affected by pollution and chemicals that penetrate their body tissues. Climate change is a potential danger as water properties change, but the effects on this cetacean are not yet clear.

This cetacean is in Appendix II of CITES (Convention on International Trade in Endangered Species of Fauna and Flora) which includes species whose international trade must be regulated. No other conservation strategies are known.

References

http://www.iucnredlist.org/details/16564/0
ftp://kim.ece.buap.mx/pub/Secretaria_Academica/TITULACION%20FCE/COMO%20ELABORAR%20LA%20TESIS/ALGUNOS%20TIPS%20PARA%20ESCRIBIR%20LA%20TESIS/MANUAL%20DE%20REDACCI%D3N%20CIENT%CDFICA/lectura3.pdf

http://animaldiversity.org/accounts/Peponocephala_electra/

http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/melonheadedwhale.htm

INFORMATION AND CHARACTERISTICS.

The Long-finned pilot whale is a cetacean member of the Delphinidae family, and one of the largest members of this group. Although it is commonly called “whale,” it is not a whale of the suborder Mysticeti. However, this colloquial name comes from its size and behavior.

The first word of its scientific name means something like “balloon head” as the Latin word “globus” means “balloon or ball” and “cephalas” means “head.”

Order: Cetacea
Family: Delphinidae
Genus: Globicephala

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

Morphology.
It is a relatively large animal with a robust body. It has a head with a bulbous forehead product of the bulging melon. Its beak is very short, and the long and curved line of the mouth gives it a face of a perpetual smile. The pectoral flippers are very long and correspond to a fifth of the total length of its body.

Weight and size.
The female is about 5.8 meters long. There is sexual dimorphism consisting of a bigger growth of the male, which reaches 7.6 meters in length. The female has a body mass of about 1,300 kilograms while the male weighs up to 2,300 kilos.

Skin Coloration.
The skin has a dark gray or black color in the upper dorsal area. The lower ventral region has a long, light gray, anchor-shaped patch that starts from the chest and ends around the genital slits. Behind the dorsal fin lies a small, light, saddle-shaped patch.

Physical characteristics.
It is a little difficult to distinguish this species from the short-finned pilot whale (Globicephala macrorhynchus) except for the length of the pectoral flippers which are larger in Globicephala melas than those of its relative.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

The Long-finned pilot whale is distributed in the temperate and sub-polar zones of the southern hemisphere and the northern hemisphere and is absent from the tropical areas and the regions near the equator. In the North Atlantic is present in coastal waters and deep waters that include the Mediterranean, Barents and the North Seas and the Gulf of St. Lawrence. It is presumed extinct in the northern Pacific Ocean, but the western part may still be populated. Northern Scotland, Ireland, and Great Britain also have this dolphin.

In the southern hemisphere, it extends as far as the Antarctic Convergence at latitude 68° S in the south part of the Atlantic and Pacific Oceans, mainly near Australia and New Zealand.

Countries and regions whose waters are home to the Long-finned pilot whale are Canada, Denmark, United States, United Kingdom, Greenland, New Zealand, Australia, South Africa, Spain, Sweden, Libya, Italy, Ireland, Iceland, Argentina, Belgium, France, Germany, Falkland Islands, Portugal and Isle of Man.

Their habitat is variable. Some individuals seem to prefer staying close to the coasts while others are always in high seas. The areas where they dwell have high ridges or are on the edge of the continental shelf. The temperature of the waters that this dolphin inhabits is between 0° and 25° Celsius.

WHAT DO THEY EAT? DIET AND EATING HABITS.

The Long-finned pilot whale maintains a diet strictly carnivorous, in its menu excel fish like herring, cod, mackerel, turbot, dogfish and Hake, and cephalopods like the squids of the genus Gonatus and the species Todarodes sagittatus. Populations living in the northeast areas of the Atlantic Ocean eat mainly squid.

A Long-finned pilot whale consumes about 34 kilograms of food per day. Their favorite time to hunt is during the night. They do it submerging 200-600 meters deep to detect prey with the help of its senses, mainly echolocation.

It does not have a good reputation among the fishermen since it takes advantage of the moments in which the boats catch fish to obtain food the easy way.

HOW DO THEY BEHAVE? BEHAVIOR.

Like most dolphins, the Long-finned pilot whale is a very sociable species that form groups of 20-100 and up to 1,000 individuals or more. It seems that family groups are more delimited and not so fluid, that is, there are not many movements between groups and they can stay in their natal pod until all their life.

The family groups are composed of breeding females with inbreeding relationship, their offspring and some males that are not the fathers of their offspring. This behavior suggests a temporary membership to mate with the available females. The social ties are incredibly strong, and some believe that this is the reason for the massive stranding on the beaches: if the theory is correct, the members of a herd follow the one or those who stranded first.

Clicks, whistles, and pulsed sounds are standard in their communication processes.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

The polygamy of the Long-finned pilot whale is evident when a male goes to a pod different from his own in search of a receptive female to mate. The male reaches sexual maturity at around 12 years of age and females approximately at six years.

The courtship process is not very “kind,” on the contrary, the male exhibits an aggressive behavior consisting of blows with his melon to his partner’s melon. If it is successful then it mates, this can happen during any time of the year but more frequently in spring and summer.

15 or 16 months after mating, the female gives birth to 1 offspring of 1.2 to 2 meters in length which is the subject of exclusive maternal care for at least two years.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation Status: “Data Deficient.”

While humans keep destroying nature, species like the Long-finned pilot whale fear for their survival on Earth. Since the nineteenth century, this and other cetaceans were hunted in the waters of Newfoundland, Greenland, Denmark, Iceland, Norway, Scotland and other countries for their meat, fat, and oil. Over time, overfishing led to the gradual disappearance of the Long-finned pilot whale in the North Atlantic.

Nowadays the practice no longer has the same importance that once but is still realized in the Faroe Islands. Direct hunting has ceded its position as the leading threat to the species to bycatch, but other dangers menace this cetacean: the contamination of its habitat with chemical substances and heavy metals as well as the strandings that occur when fishing boats lead the Long-finned pilot whale towards the beaches.

The Red List of the International Union for the Conservation of Nature (IUCN) does not have enough data to assess its conservation status. In this regard, the UK Biodiversity Action Plan considers the protection of the species to be of paramount importance, and the Wildlife and Field Act 1981 declares the illegality of its capture, killing or any other activity that could be harmful to the life of whales and dolphins in the waters of the United Kingdom.

Conservation efforts should include ensuring the protection of the species from the entanglement they suffer in several kinds of fishing nets.

References

Mediterranean Marine Mammal Ecology and Conservation. Academic Press, 2016.

William F. Perrin, Bernd Würsig, J.G.M. ‘Hans’ Thewissen. Encyclopedia of Marine Mammals. Academic Press, 2009. Page 847.

http://www.cms.int/reports/small_cetaceans/data/G_melas/g_melas.htm

http://www.fisheries.noaa.gov/pr/species/mammals/whales/long-finned-pilot-whale.html

INFORMATION AND CHARACTERISTICS.

It is one of the two species of common dolphins that belong to the genus Delphinus. Therefore it has a similar appearance to the short-beaked common dolphin (Delphinus delphis), and they were considered part of the same species until the mid-1990s when they were separated and recognized Delphinus capensis as a different species.

Its scientific name comes from the place where it was found in the 19th century, in 1828: the Cape of Good Hope. There are two subspecies of Long-beaked common dolphins, Delphinus capensis capensis and Delphinus capensis tropicalis.

Order: Cetacea
Family: Delphinidae
Genus: Delphinus

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

If a person is on the high seas, it ‘s hard to distinguish this species from Delphinus delphis, but the former dolphin has a longer and thinner snout than the latter.

Weight and size.
It is a medium-sized dolphin with a length estimated between 1.9 and 2.5 meters being the males slightly larger than the females. In average, individuals can weight between 80 and 235 kilograms but usually not more than 150 kilos.

Morphology.
The shape of its body is fusiform but robust. In the center of the dorsum, it has a curved dorsal fin. Its head is less rounded than other species since the melon rises from the snout at a small angle.

Skin Coloration.
It has a coloring pattern that extends from the sides of the body to the dorsal fin. The upper area is dark, the lower is white, and both pectoral flippers have the same dark color of the top. The dark color can be dark gray or dark brown, while the light color can be white or light yellow.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

The Long-beaked common dolphin inhabits specific areas of the Atlantic, Indian and Pacific Oceans. It is possible to find it from the west coast of the United States to Baja California in Mexico. There are also populations in Mexico, Peru, Chile, Venezuela, Brazil, Argentina, West Africa, South Africa, Madagascar, the Arabian Peninsula, India, Indonesia, China, South Korea and southern Japan.

The subspecies Delphinus capensis capensis dwells on the east coast of South America, western Africa, southern Japan, Korea, northern Taiwan, South Africa, and California in the United States to Peru. Delphinus capensis tropicalis lives in the Indo-Pacific up to the Gulf of Thailand.

The Long-beaked common dolphin typically prefers temperate water habitats about 180 kilometers away from the coasts on the continental shelf, at lower depths than Delphinus delphis. It does not usually congregate around the oceanic islands and do not inhabit the high seas.

WHAT DO THEY EAT? DIET AND EATING HABITS.

The Long-beaked common dolphin has a carnivorous diet abundant in small fish, cephalopods, and crustaceans. In the north of the Gulf of California, this dolphin gathers with others of the same species forming pods of tens to thousands of individuals, and cooperate to catch prey. What they do is chasing and herding large schools of fish, and when they become disoriented, they keep the school together to expedite its consumption.

The above involves submerging at about 280 meters deep for a maximum of 8 minutes before surfacing to get oxygen. Their hunting and feeding activities occur near the coasts, in shallow waters. Some of its habitual prey are:

– Sardines and Herrings (Family Clupeidae).
– Anchovies (Genus Anchoa).
– Hakes and Cod (Order Gadiformes).
– Squid (Order Teuthida).
– Krill (Order Euphausiacea).

Although group hunting is well-known in the Gulf of California, most think that something similar happens in other regions where this dolphin lives.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

The Long-beaked common dolphin reaches sexual maturity when the specimen exceeds 2 meters in length, but the age at which it occurs varies according to the geographic region in which the dolphin lives. In males can happen between 2 and seven years and in females between 3 and 12 years.

Mothers give birth every 2 or 3 years. After mating, usually during the spring and autumn months, females have a gestation period of 9-11 months after which one single offspring is born with a weight of approximately 10 kilograms and a length of 0.8-1.0 meters as well as a coloration less dark than that of adults. The mother weans the baby about six months after birth.

It is interesting to know that captive individuals of this species have successfully mated with bottlenose dolphins, resulting in hybrid offspring capable of reproducing. This species lives in the wild about 22 years.

HOW DO THEY BEHAVE? BEHAVIOR

Delphinus capensis is one of the most gregarious animals in existence, and its pods are made up of hundreds or thousands of individuals that may organize into smaller groups of about 10-30 members according to age and gender. Sometimes they swim along with other cetaceans such as pilot whales (Globicephala).

These dolphins are socially active, very energetic and even curious as they approach the boats and stay close to them for a long time. They are fast swimmers and perform various types of acrobatics, among them, riding the bow waves of boats and jumping out of the water; They also whistle with their heads out of the water.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation Status: “Data Deficient.”

This species has a conservation status as “Data Deficient” in the Red List of the International Union for the Conservation of Nature (IUCN). It is sometimes intentionally hunted (sometimes harpooned) in Japan, northern Venezuela, areas of the Caribbean, Peru, and West Africa to get their meat for human consumption or as bait. Other direct catches are to get them for aquariums or parks.

Bycatch is probably the greatest threat to their survival. In China, Southern California and other parts of the tropical eastern Pacific, it is frequent their entanglement in gillnets, driftnets, and trawl nets.

On the other hand, pollution also threatens their survival. According to researchers, they found remains of organochlorines in their fat.

The good part of this scenario is that the species is under the protection of the Marine Mammal Protection Act of 1972, which applies measures that prevent dolphin degradation.

References

William F. Perrin, Bernd Würsig, J.G.M. ‘Hans’ Thewissen. Encyclopedia of Marine Mammals. Academic Press, 2009. Page 255.

http://www.cms.int/reports/small_cetaceans/data/d_capensis/d_capensis.htm

http://www.fisheries.noaa.gov/pr/species/mammals/dolphins/common-dolphin_long-beaked.html

https://en.wikipedia.org/wiki/Short-beaked_common_dolphin