Irrawaddy Dolphin Facts

(Orcaella brevirostris)

INFORMATION AND CHARACTERISTICS.

The Irrawaddy river dolphin is a species that belong to the group of oceanic dolphins. Paradoxically, it is not a dolphin exclusively of freshwater. It is closely related to the Orca (Orcinus orca), and it is one of the most threatened extant dolphins.

In Laos, the inhabitants have the belief that humans can reincarnate in these dolphins.

Order: Cetacea
Family: Delphinidae
Genus: Orcaella

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

The Irrawaddy dolphin is a singular-looking dolphin, whose body differs from the stereotype of the best-known dolphins. Physically it is similar to the beluga whale (Delphinapterus leucas), another toothed cetacean and marine mammal.

Weight and size.
The species exhibits sexual dimorphism since the male tends to be larger and heavier than the female. An adult has a weight of approximately 130 kilograms and a length of 2.3 meters.

Morphology.
The body of this dolphin is very robust. It has a rounded head and a very bulging forehead that extends from above the mouth. Its dorsal fin at the back end is small and has a triangle shape while the pectoral flippers are long, wide and also triangular. It has no heart sphincter, and as with other dolphins, its stomach splits into several compartments.

Skin Coloration.
The skin in the dorsum and the sides has a blue or gray color, but the color in the ventral area is slightly lighter as well as in the last part of the back.

Distinctive Characteristics.
This dolphin lacks a beak, and since its neck is very flexible, it has wrinkles behind the head as a result of this capability.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

The Irrawaddy dolphin thrives in tropical and subtropical waters of the Indo-Pacific region on and near shallow coastal waters. It inhabits Southeast Asia from Borneo and the islands of the Indonesian Archipelago to Papua New Guinea. Three subpopulations live in freshwater rivers:
– Ayeyarwady in Burma,
– Mahakam in Indonesia
– Mekong in Laos.

They also live in two brackish water systems:
– Chilika Lake in India
– Songkhla Lake in Thailand.

The countries where this species dwells are Vietnam, Cambodia, Singapore, Thailand, Indonesia, Burma, Laos, Philippines, Bangladesh, Brunei, India, and Malaysia.

It inhabits coasts, rivers, estuaries, deltas and large lakes of its distribution zone, regularly near the mangroves. Almost all sightings have happened not more than 1.6 kilometers away from the coast and a less than 5 kilometers, and apparently, they do not usually live in deep waters.

WHAT DO THEY EAT? DIET AND EATING HABITS.

It is a carnivorous cetacean that feeds on several species of cephalopods, fish, crustaceans and fish eggs. It establishes a strategy of cooperation in groups composed of 6-15 dolphins. To hunt, they can spit water to attract more fish and even hit large species with their lower jaw, perhaps in an attempt to play before eating.

In some regions of Asia these dolphins fish in cooperation with local fishers which call them, and surprisingly the dolphins come swimming in semicircles and hauling the fish to the surface. Thus both parties benefit since the dolphins feed themselves with the fish stunned or trapped in the edges of the boat.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

There is not much information about the mating habits of the Irrawaddy dolphin. Individuals reach sexual maturity at around 3-9 years of age and the mating season is variable. For example, in the northern hemisphere dolphins mate from December to June and births occur between June and August.

The female delivers one single offspring after a gestation period of 14 months. Researchers assume that, just as in other species, males mate with and compete for several females.

At birth, the offspring weigh about 10 kilograms and measure about 1 meter. Six months later they are already able to consume fish, and after one year and a half, they are usually completely weaned.

HOW DO THEY BEHAVE? BEHAVIOR

This dolphin shows high sociability inside and outside its pod because its groups are composed of 5-57 members but also occasionally meet with other species of dolphins. The most common practice is that they live in small groups of 3 to 6 members.

This species makes slow movements and has less activity than other dolphins; it usually breathes taking out only the head out of the water. In the same way, they take a look around: with the head as the only visible point. However, it has been seen jumping, making bubbles and hitting the water with its flippers and tail.

Their territories cover about 35 kilometers in length. Individuals from eastern Borneo make daily migrations to the Mahakam River but always return to their area at night. For their part, those living in Indonesia move into the River tributaries at high tide and to the river when the tide is low.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

There are no identified natural predators of this species, and only the humans represent a threat to them.

The low reproduction rate and the human-related threats contribute to the rapid decline of the Irrawaddy dolphin populations and the danger of extinction in some areas. There are no known natural predators of the species, so it is essential that the humans stop threatening this dolphin.

Individuals are often trapped in gillnets or die after dynamite explosions when fishers use such method. It is also gets electrocuted with nets used in electric fishing. To make things worse, water pollution and dam construction destroy and negatively modify their habitat and puts them in danger.

Fortunately, this dolphin under protection in Laos, Vietnam, and Cambodia, and Bangladesh, India, Laos, Malaysia, Burma, and Thailand banned its hunting. In fact, in Burma, there is a reserved area of about 74 kilometers of the river Ayeyarwady.

The Whale and Dolphin Conservation (WDC) organization dedicated to the conservation of whales, dolphins, and porpoises created an Operation Plan for the Conservation of the Irrawaddy Freshwater Dolphin Populations given the potential extinction problem in Southeast Asia.

References

https://en.wikipedia.org/wiki/Irrawaddy_dolphin

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

Jefferson, Webber, Pitman. Marine Mammals of the World: A Comprehensive Guide to Their Identification. Academic Press, 2015. Page 183.

https://www.worldwildlife.org/species/irrawaddy-dolphin

(Pontoporia blainvillei)

INFORMATION AND CHARACTERISTICS.

It is one of the smallest dolphins in the world and curiously, although it is a member of the group of river dolphins, it does not live exclusively in freshwater. This dolphin was described initially in 1844. Also known with the name of Franciscana dolphin, it is the only member of its family.

Order: Cetacea
Superfamily: Inioidea
Family: Pontoporiidae
Genus: Pontoporia

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

This dolphin rivals Hector’s dolphin (Cephalorhynchus hectori) for the title of the “smallest dolphin in the world, ” but the individuals of this species have slightly larger dimensions.

Weight and size.
La Plata dolphin females grow faster than males, and the former are also larger than the latter when adults. A female length is around 1.8 meters; The male is only 1.6 meters. Other estimates indicate that females and males can be as small as 80 and 76 centimeters, respectively. The weight is around 50 kilograms.

Morphology.
From their small body stands a large beak and a big head with symmetric facial skull and a rounded forehead. Their fused vertebrae provide a very flexible neck. Just above the fold of the neck is the blowhole which has a semilunar shape and several centimeters further back appears a medium-sized dorsal fin, with a triangular shape and a rounded tip. They have flattened pectoral flippers, where small ridges protrude in males when they reach adulthood.

Skin Coloration.
The color of the dorsal area (top) is usually gray or brownish. The belly is white. Young specimens tend to be browner than adults, and they have seven hairs on the upper jaw.

Distinctive characteristics.
Its narrow beak is the most outstanding feature as it has the largest ratio of all cetaceans when comparing its body size against its beak.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

It is distributed only along the eastern South American coasts of the Atlantic Ocean from Brazil to Argentina, passing through Uruguay in tropical and temperate waters. It inhabits from the north of the San Matías Gulf in Argentina to the state of Espírito Santo in southeast Brazil. This range is misleading because the species is not evenly distributed in it but is absent in some areas.

It lives about 55 kilometers from the coasts in murky and shallow ocean waters with depths ranging from 6 to 35 meters, but they venture into brackish estuaries. Tides have a significant influence on their habitats.

WHAT DO THEY EAT? DIET AND EATING HABITS.

It consumes a wide variety of pelagic and demersal fish, as well as cephalopods and crustaceans. It is, therefore, a carnivorous animal whose teeth serve to hold the prey, including shrimp and squid.

Most of their prey have lengths around 10 centimeters, but they can consume everything that fits into their mouth. Their favorite prey is:

– Longfinger anchovy (Anchoa filifera).
– American Coastal Pellona (Pellona harroweri).
– Corvina (Isopisthus parvipinnis).
– Squid (Loligo sanpaulensis).
– Cynoscion striatus.
– Blonde Corvina (Micropogonias jurnieri).
– Banded Croaker (Paralonchurus brasiliensis).

This dolphin spends a lot of time looking for food during the high tide and displays cooperative hunting techniques in which all members of a group help to catch food.

HOW DO THEY BEHAVE? BEHAVIOR

The La Plata dolphin is a diurnal cetacean which performs its principal activities during the day. Although it is sociable as many other dolphins, their pods are composed of 2-15 individuals but can be as many as 20 or 40. The social structure is possibly matriarchal, that is when an adult female lead the pod and the groups are made up of individuals related to each other.

It is not common to spot this dolphin, and its movements are regularly slow: its speed when swimming is 0.09-1.8 meters per second. If the tide is low, it travels with the members of its pod.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

Unusual in the world of dolphins, this species is believed to be monogamous and reach sexual maturity early in life. Females reach sexual maturity at around three years and males at two, but this varies among populations of the north and the south of its range of distribution.

Females have one offspring each year between October and January after a mating usually between January and February. These times indicate that the gestation period lasts 10.5-11.2 months.

The calf spends a lot of time with its mother and for a time is fed only with breast milk. At 8-9 months of age is weaned, when it measures about 105 centimeters in length.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation Status: Vulnerable.

The La Plata dolphin has a conservation status of “Vulnerable” according to the classification of the Red List of the International Union for the Conservation of Nature (IUCN). This situation is the result of bycatch in gillnets, the contamination of their habitat and the noise pollution. Its high mortality is, therefore, a consequence of human activities, and 500-800 individuals of this species die every year.

La Plata dolphin is in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which lists species whose trade requires strict regulation.

References

http://www.cms.int/reports/small_cetaceans/data/P_blainvillei/p_blainvillei.htm

Jefferson, Webber, Pitman. Marine Mammals of the World: A Comprehensive Guide to Their Identification. Academic Press, 2015. Page 355.

http://www.iucnredlist.org/details/17978/0

http://ar.whales.org/guia-de-especies/franciscana

Obviously, the distribution and habitat are different for each dolphin species, but usually, they avoid extreme cold waters, so they are not found in the polar zones.

Dolphins are found living in bodies of water around the world. They inhabit all of the oceans and some important rivers. Most of them live in saltwater, but a few species thrive in freshwater.

The habitat of dolphins varies according to environmental factors and food accessibility. They are smart creatures with the intelligence to modify their habitat when needed for survival.

PARTICULAR DISTRIBUTIONS

For example, the Bottlenose Dolphin dwells in all of the oceans, and they tend to live close to the coastline. Migration is a big part of life for some dolphins. They have to move where there is enough food; This is why some locations where there used to be dolphins either have very few or none anymore. Even changes in water temperatures can be reasons for them no longer to return to locations they once called home. Some successfully migrate hundreds of miles annually.

Open water species tolerate colder temperatures than coastal dolphins.

The Atlantic, Pacific and Indian Oceans and their seas host a large number of dolphin species since they prefer tropical, subtropical and warm waters. However, talking about the particular distribution of dolphins means addressing the place where each species live as they differ from each other.

Also, some species are distributed over large areas while others may inhabit a small region. Other species are particularly endemic to a zone, and some may have different populations scattered over an extensive range. Each species is a different case.

Two common dolphins jumping in the Sea of Cortes, Mexico.

The Pacific Ocean is habitat to several species, such as the bottlenose dolphin (Tursiops truncatus), perhaps the best-known dolphin, with a vast territory ranging from Japan to Australia and from the southern United States to Chile and Hawaii. In the Atlantic, the bottlenose dolphin dwells from North America to southern Argentina in the western part of this ocean and from Norway all the way down to the coasts of South Africa in the east. This species is also common in the Mediterranean Sea and the Indian Ocean.

Some dolphins out there live in much smaller habitats. For example, the Yangtze River Dolphin only dwells in the river of the same name. Hector’s Dolphins inhabit the coastal areas of New Zealand. They tend to be scattered there around the South Island.

The Short-beaked Common Dolphin (Delphinus Delphis) mainly inhabits the Mediterranean Sea and the northern part of the Atlantic Ocean. The Chinese white dolphin (Sousa chinensis) only dwells in the waters of the Indian and Pacific oceans.

Additionally, five river species exist that only inhabit the freshwaters of the Amazon, Ganges, Yangtze, Rio de la Plata and Indus rivers respectively.

GENERAL AND SPECIFIC HABITATS

The habitats of dolphins are also very diverse. They can be found in ports, bays, gulfs and estuaries and frequently in the shallow waters of the continental shelves. Previously it was believed that dolphins could not dive more than 200 meters deep, but apparently, some species have the feasibility of diving about 300 meters deep, a conclusion reached by finding remains of benthic fish in the stomachs of some specimens.

Some individuals prefer living in the open ocean while others fancy the conditions near the coasts. The Hector’s dolphin (Cephalorhynchus hectori), for example, can live only in shallow waters near the coastline. In contrast, the Spinner dolphin (Stenella longirostris) lives in the pelagic zone of high seas.

Open ocean dolphins seem to tolerate cold temperatures better than the coastal species. They rarely get close to the coasts. In contrast, coastal dolphins prefer warm and tropical waters, and their small body allows them to enter narrow and shallow places such as estuaries and river channels.

One thing is for sure: Dolphins visit areas with abundant prey within their habitats. Whether or not it is shallow water, most of these cetaceans prefer the pelagic area of ​​the sea where is easier finding and catching food. If the food supply decreases, dolphins tend to migrate to areas where there is no shortage, so their eating habits also change.

Since most species do not tolerate frozen waters they can migrate in search of warmer places during the seasons when temperatures drop, and vice versa. Dolphins also consider the migration patterns of their usual prey and their breeding habits to move from one site to another and perform seasonal migrations.

River Dolphins, for their part, inhabit the river basins of their distribution areas, along with the banks of the main channels and smaller channels. Some river dolphins venture to explore the forests when the rainy season floods them.

If you want to know the distribution and habitat of a particular species, do not hesitate to visit the Species section.

References

bioexpedition.com/dolphin-habitat-and-distribution/

https://seaworld.org/en/animal-info/animal-infobooks/bottlenose-dolphins/habitat-and-distribution/

http://www.scielo.cl/pdf/revbiolmar/v36n1/art11.pdf

http://www.iucnredlist.org/search

Sam H. Ridgway, Richard John Harrison. Handbook of Marine Mammals: The Second Book of Dolphins and the Porpoises, Volumen 6. 1998.

(Inia Geoffrensis)

INFORMATION AND CHARACTERISTICS.

Other common names of this dolphin are Boto, bufeo and pink river dolphin. Among the river dolphins, this species is the largest, best known, most researched and with the largest population. There are three subspecies of Amazon river dolphin:
– Inia geoffrensis geoffrensis.*
– Inia geoffrensis humboldtiana.
– Inia geoffrensis boliviensis.

* Recently (2014) this subspecies was split from Inia geoffrensis and defined as an independent species with the name Araguaian River dolphin as mitochondrial studies determined that they are indeed different species.

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

Morphology.
It is a robust dolphin with a very long snout easily distinguishable. It has a bulbous forehead due to a pronounced melon, chubby cheeks, small eyes and a remarkably flexible neck since its vertebrae are not fused. The pectoral flippers are large and have a triangle shape. He has a heterodont denture since his teeth are conical in the front of the jaw while the back pieces have a flange.

Order: Cetacea
Superfamily: Inioidea
Family: Iniidae
Genus: Inia

Weight and size.
Adults are between 1.53 and 2.4 meters in length, but this depends on the subspecies in question. The largest individual recorded was a female, weighing 98.5 kilograms.

Skin Coloration.
The most distinctive feature of this dolphin is the pink color that it acquires with age. The lower part of the body is usually clearer, and some individuals have gray patches.

Distinctive characteristic.
It is the only species of cetacean with heterodont dentition, and its dorsal fin is so small that it rather looks like a triangular crest.

Amazon River Dolphin – Inia Geoffrensis.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

The Amazon River dolphin inhabits only the freshwater systems of South America. Its distribution includes the basins of the Amazon and Orinoco rivers and the tributaries of these rivers in Bolivia, Colombia, Brazil, Ecuador, Peru, and Venezuela. However, each subspecies lives in defined areas: I. g. Geoffrensis thrives in the Amazon and Araguaia river basins except for the upper Teotonio rapids in the Madeira river basin in Bolivia. I.g. Boliviensis inhabits above the Teotonio rapids in the basin of the Amazon River and, I. g. Humboldtiana dwells in the basin of the Orinoco River.

The Amazon River dolphin can live in areas of slow movement, in deep water channels, in flooded forests, in confluences where clear waters and sewage mix, in narrow channels and possibly under waterfalls and rapids.

WHAT DO THEY EAT? DIET AND EATING HABITS.

The Amazon pink dolphin consumes a variety of prey more diverse than other species of dolphins. Fish, crabs and small turtles are part of the diet of this cetacean that regularly hunts alone and consumes 2.5 percent of its total weight each day.

The diet of these dolphins includes 43 species of fish. Their favorite fish belong to the families Sciaenidae, Cichlidae, and the one of the feared piranhas, Serrasalmidae.

It is a natural hunter. Mostly active during the day, it knows that under the waterfalls or at the mouths of the rivers, it is easier to catch the fish that pass through the currents. Sometimes it looks for food at the riverbed. The hard shells of turtles do not deter this dolphin from eating these reptiles because for such prey it has a potent and long “snout” that helps break the hard parts.

Sometimes it associates with the giant otter (Pteronura brasiliensis) or the tucuxi (Sotalia fluviatilis) to hunt in a coordinated way and share the food.

HOW DO THEY BEHAVE? BEHAVIOR

Observations concluded that the Amazon River dolphin moves slowly. Its speed while swimming is only 1.5 to 3.2 kilometers per hour, but it has occasional bursts reaching up to 14 to 22 kilometers per hour.

It is not as sociable as the oceanic dolphins since it usually travels in groups of 2 or 3 individuals, mostly mothers with a calf. It is, therefore, a lone dolphin. The larger groups, with 12 to 15 members, are temporal associations with the purpose of feeding or mating.

It is somewhat shy with humans, but sometimes it shows curiosity. It is also very playful, and it has been seen pulling the aquatic grass and throwing pieces of wood. Curiously, at times its food is also its friend: it usually plays with fish and turtles.

It uses echolocation to perceive what is in its environment and capture prey. The “clicks” are the basis of their communication and reach from 16 to 170 kilohertz.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

Scientists believe that this species is monogamous, but after noticing the male’s aggressiveness during mating and the multiple scars on its body, they began considering the idea of polygamy because this is the evidence of a possible competition for females.

Males and females reach sexual maturity at about five years of age or when the former is already about 2 meters in length, and the latter is between 1.60 and 1.75 meters. When a male finds a receptive female, he communicates his mating intentions by biting the female’s flippers.

11 months after mating, a single offspring is born between May and July measuring about 0.8 meters long. The time between each birth can last up to 5 years.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation Status: Data Deficient.

The fact that the pink dolphin has a “Data Deficient” conservation status on the Red List of the International Union for the Conservation of Nature entails a danger not completely unknown, but that makes difficult to implement conservation strategies. It is evident that the species faces a serious problem for survival in its natural habitat and until 2011 had a classification as a vulnerable species.

Their principal anthropogenic threats are:

– Overfishing.
This practice reduces the availability of food for the species.

– Dam construction.
The development of hydroelectric dams in the river, alter the conditions of their habitat separating populations which reduce the availability of mating partners and the genetic diversity.

– Uncontrolled logging.
When logging for converting the forests into agricultural land, the number of animals consuming the products of the trees decreases, and the amount of food for the Boto reduces in consequence.

– River traffic.
Excessive boat traffic causes collisions with these dolphins where the propellers cause them serious injuries.

– Habitat pollution.
The increasing contamination of the river brings all kind of problems to these dolphins and reduces their chances to survival drastically.

In their natural habitat, alligators, jaguars, anacondas and Bull sharks (Carcharhinus leucas) are their major threats. In Brazil, Peru, Venezuela, Colombia and Bolivia, there are laws to protect this species. Since 1986, the Cetacean Specialist Group of the Species Survival Commission has been working to protect and design conservation strategies for all endangered river dolphins.

Amazon River Dolphin Infographic!

(Click for expand)

References

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

William F. Perrin, Bernd Würsig, J.G.M. ‘Hans’ Thewissen. Encyclopedia of Marine Mammals. Academic Press, 2009. Page 26

Sy Montgomery. Journey of the Pink Dolphins: An Amazon Quest. Chelsea Green Publishing, 2009.

http://www.iucnredlist.org/details/10831/0

http://ufdc.ufl.edu/UFE0046251/00001

]]> https://www.dolphins-world.com/river-dolphins/ Wed, 29 Jan 2014 05:27:29 +0000 http://www.dolphins-world.com/?p=104 River Dolphins Facts – Freshwater Dolphins

Introduction

There are only five species of dolphins that are able to thrive in freshwater and the Amazon River Dolphin is one of them. Many people assume that all dolphins live in saltwater so this is interesting to learn if you weren’t aware of it. There are several subspecies of River Dolphins to learn about.

Description

Depending on the location where they reside, River Dolphins will vary in size. Some of them can be up to 8 feet long but most of them are much smaller than that. They can also be found in a variety of colors. Some that you are known to exist include gray, black, brown, pink, yellow, and white. Due to the many different colors, they are often mistaken for other forms of aquatic life.

Distribution

The River Dolphin, as the name implies, lives in Rivers and that means they are able to survive in freshwater. They tend to stick to the brackish and coastal regions. They are found in the

Amazon, Ganges, Yangtze, Mekong, and Indus Rivers. Many of these rivers are home to very poor villagers and the locations can be very dense.

Plenty of these rivers are filled with dark, murky water and plenty of pollution. What is very interesting is that they can live in conditions that other species of dolphins would not be able to. It isn’t understood why this is possible, and more research has to be done. With so few species being able to live in freshwater, there are some theories but no definite answers at this time.

Behavior

River Dolphins are very social, and like others, they form pods. There can be just a few of them or more than 100 in a pod. They do form very strong bonds and they are quite protective of each other. The young tend to be secured in the middle of the pod in order to keep them safe. The females have also been noted to care for the young of each other in a cooperative effort.

These dolphins are believed to be very social and to have a complex hierarchy that can be hard to fully understand. They tend to have some pods that have primarily females or males in them. This could be part of their social organization.

Feeding

Fish are the main components of the diet for the River Dolphin, and they can eat large amounts of them daily. They use a variety of differenttechniques to get the schools of fish with ease. Usually, these efforts involve teamwork and collaboration that is very in sync and interesting to observe. For larger pods, they often break up into smaller groups for feeding purposes to be carried out.

Reproduction

The time of year for mating can vary based on the location of the River Dolphin. The females usually are ready to mate around 8 years of age and for the males it is about 10 years old. The males may heavily compete with each other for mating. The young will be born from 10 to 12 months later, tail first.

The pod is very protective and they will help the mother during the birthing process. They will protect the young calf and help it to the surface for air. They will also help keep predators away. The young will grow rapidly due to the fat content found in the milk that the mother produces. They will drink the milk for 1 ½ to 2 years, but they will also start to consume fish when they are about 6 months old.

Conservation Status and Threats

The River Dolphin is considered to be in a range from vulnerable to critically endangered. It is hard to get a good idea of the number of them due to the different species and their habitat. There are plenty of issues for the River Dolphin to worry about in their natural habitat. They may be caught up in fishing nets or collide with boats. Heavily pollution has played a vital role in the reduction of numbers of them in many locations.

Some of the conservation efforts involve fishing with better equipment and tools. However, since the rivers where plenty of the dolphins live are around very poor cultures that can be tough to improve. Overfishing is also a concern as the villagers heavily depend on the food for survival. Yet that can leave a lack of food for the dolphins to survive. Pollution problems are also higher in areas where they don’t have proper water and sewer systems in place.

One of the River Dolphins called the Baiji, has declared functionally extinct in December of 2006. The last time one of them was seen in the wild was in 2004. While there were some reports in 2007 of sightings of one in the Yangtze River, it couldn’t be confirmed.

The Amazon River dolphin, also known as Boto (Inia geoffrensis), is a freshwater dolphin that lives in the Amazon River and the Orinoco River systems which include several countries in South America.

These dolphins are Pink Dolphins move around these rivers to every place where they can reach without going to the ocean.

Other pink dolphins such as the Chinese white dolphin (Sousa chinensis) live in an area that covers the east and west coasts of northern Australia, eastern China, the Indo-Malayan archipelago, and the Bay of Bengal in the east of India.

Dolphins live in all oceans of the planet and even in some important rivers.

While not all species of dolphins live everywhere, there is a species for each environment. Specifically one of the best-known species, the bottlenose dolphin lives in every ocean of the world except the Arctic and the Antarctic oceans.

The Atlantic spotted dolphin, lives all over the tropical and temperate areas of the Atlantic Ocean avoiding the Artic and Antarctic regions.

The Pink Dolphin lives in the Amazon river.

//www.youtube.com/watch?v=RVefMJKZaZY

Yangtze river dolphins, also known as Baiji are freshwater dolphins who lived in the Yangtze River in China.

Due to excessive fishing and industrialization around the Yangtze River, this species of dolphin is critically endangered, and even some affirm that it is already extinct.

Baiji used to live along 1000 miles of the middle and lower parts of the Yangtze River from the mouth of the river near Shangai to Yichang in the west.

Most dolphins live in the ocean, but there are some species which live in freshwater rivers.

While most known species like the bottlenose and the spinner dolphins live in the sea, some other live in some of the most famous rivers in the world like the Amazon river, the Ganges River, the Yangtze River, the La Plata River and the Indus River.

The best known of all the freshwater species is the Amazon Pink Dolphin, also known as “Boto” who lives in the Amazon river.

Different species of dolphins live in the diverse climates that exist in the world.

From the cold waters of the north pole where some populations of killer whales dwell to the tropical waters of the Caribbean where the bottlenose dolphin live.

Even more, some dolphin species live in the tropical temperatures of rivers like the Amazon or Orinoco.