(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

There are five species of dolphins that make their homes in rivers, being the most popular of them the Pink Dolphins also known as Boto, Boutu or Amazon River dolphins as it inhabits the Amazon River.

The scientific name of the Pink Dolphins from the Amazon is Inia Geoffrensis and they belong to the genus Inea, part of the family Platanistoidea, which is conformed by the five species of river dolphins.

Pink dolphins are not the same dolphins that you would see in the ocean; they have special adaptations to their habitat. In fact, river dolphins are only distantly related to sea dolphins.

They belong taxonomically speaking to different families. The oceanic dolphins belong to the family delphinidae while river dolphins belong to the family Platanistoidea as we said above.

Among the five species of river dolphins, Amazon pink dolphins are considered the most intelligent of them, with a brain capacity 40% larger than that of humans.

Pink dolphins inhabit the Amazon River, but they can also be found in the Orinoco basins and the upper Madeira River as well. While they are mostly pink, these dolphins have various colored skins, which can be light gray, pink, or brown.

The Amazon River pink dolphins conform the largest population of river dolphins in existence as the other four species are functionally extinct or close to extinction.

The river dolphins are among the most endangered species of all the world’s cetaceans. Pink dolphins have been listed by the International Union for the Conservation of Nature (IUCN) as a “vulnerable species-threatened” and recently was moved to “endangered species-threatened”

These friendly and social creatures have been living for centuries in the Amazon and its tributaries, but the accelerated destruction of the Amazon basin have put them in a every time more dangerous situation.

The raise in contaminant levels of mercury have caused and increased number of deaths among pink dolphins, especially near gold mines where mercury is used as part of the gold mining process.

The increase of traffic in the Amazon River, also threatens these creatures as they are curious by nature and they sometime approach to vessels where they are easily hurt by the sharp propellers.

Additionally, the noise produced by engines and motors and the sound pollution caused by them, has been considered to produce a disorienting phenomenon in their navigations systems, causing the death of many pink dolphins.

What do Pink Dolphins Eat?

Pink dolphins eat crabs, catfish, small river fish and even small turtles.

As crabs and turtles have to be catch mainly at the bottom of the river, pink dolphins spend a lot of time while swimming looking at the bottom of the river for food.

The boto cervical vertebrae are not fused allowing them to move their head up to 180 degrees, which is a great help for hunting in shallow waters and floodplains.

Hunting fish require some techniques like herding, where they round a fish pod to concentrate fish and take turns for feeding. This procedure is largely used by their oceanic cousins.

Physical Description of Pink Dolphins

In the Amazon Region…There is a legend about the Boto or Pink Dolphin. According to the legend, the Boto turns from man to dolphin and backwards, changing shape at will.

The legend also states that when dolphins find young women on the shore, they changes shape and impregnate them.

This comes from the similarites between certain body parts of the Boto and humans.

There are several other superstitions about the Pink Dolphins in the Amazon River and around.

Pink dolphins can be found in pink, light gray or brown colors but there is not conclusive evidence of the reason why pink dolphins are pink.

It could be an adaptation to the river life or caused by the presence of capillaries near the surface of the skin what provide them such impressive color. Additionally, pink dolphins get pinker when they are excited or surprised, resembling blushing in humans.

The Amazon River dolphin is between six and eight feet long, and weighs between 185 and 355 pounds when it is fully grown.

River dolphins are typically smaller than sea dolphins but they have longer snouts, an adaptation provided by evolution, which is needed to hunt at the bottom of the river. River dolphins also tend to have more pointy teeth than sea dolphins.

Most species of river dolphins are almost blind, due to navigating muddy waters, but their brains are extremely large and well developed, however pink dolphins are considered to have a relatively good sight.

Unlike sea dolphins, river dolphins have what resembles fingers on the ends of their flippers, and their dorsal fins are much smaller than that of sea dolphins or even have humpbacks instead of dorsal fins like the pink river dolphin.

//www.youtube.com/watch?v=20h9Tg8BCYU

Behavior of Pink Dolphins

Pink dolphins appear to be the friendliest of all the river dolphins when approaching to humans and some stories of people being pushed to the shores by them are common among some tribes in the Amazon.

They swim up to 30 kilometers in one day, although they usually swim slowly looking for food at the bottom of the river.

“Amazon River Pink Dolphins are typically smaller than sea dolphins but they have longer snouts, an adaptation provided by evolution…”

How do Pink Dolphins Reproduce?

Males and Females mate to start a gestation period which is believed to last from nine to twelve months. Copulation is performed between males and females belly to belly.

Calves are born about 75 cm long and weighing a bit more than 1 Kg.

Pink dolphins deliver their babies when the Amazon River is at its high between the months of May and July.

Pink Dolphin Conservation

The World Conservation Union, also known as International Union for the conservation of Nature and Natural Resources (IUCN) is an international organization based in Gland, Switzerland, devoted to the conservation of natural resources.

It was founded in 1948 and groups 83 states, 108 governmental agencies and more than 10,000 scientists and experts from countries around the world.

The IUCN publishes a red list of threatened species which is a reference in the field and the base for conservation of species.

Union for the Conservation of Nature (IUCN)

Frequently Asked Questions about Pink Dolphins

How Do Pink River Dolphins Reproduce

Why Are Pink River Dolphins Endangered

Why Are Pink Dolphins Pink

Where Do Pink Dolphins Live

For this, a group of researchers, including collaborators from the WWF, prepare special artifacts to learn about the lives of these dolphins and they even get into the water for best results. This species inhabits the fresh waters of South Asia and has the capability to regulate their body temperature, as they can live in waters from eight degrees to 33 Celsius degrees.

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

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//www.youtube.com/watch?v=20h9Tg8BCYU