Pink River Dolphin

The Chinese river dolphin is a freshwater dolphin and one of the most endangered animals on Earth. It is found in the Yangtze River in China. Under the Endangered Species Act, NOAA Fisheries must list threatened and endangered marine species regardless of where they are found. The Chinese river dolphin is listed as endangered under the ESA. Pink dolphins Peru. In Peru, The Pink dolphins also live in the Amazon River basin. Some of the best places to see them are Iquitos, the Pacaya-Samiria Reserve, and the Upper Amazon River (for example, near Santa Rosa). Pink dolphins in Colombia. The Colombian Amazon is the area you should head to see the pink dolphins in nature.

The name “pink dolphin” generally refers to the Amazon River dolphin (aka the Boto dolphin), however the Chinese river dolphin (aka the Baiji dolphin) is also known for its pinkish skin tone.

This species gets its name from its pinkish skin tone which is present throughout the dolphin’s body; however some of these dolphins may also possess a grayish skin tone (generally younger offspring) rather than pink.

In terms of location these dolphins can be found living in the Amazon, Orinoco and Tocantins with the Chinese white dolphin being located in the Yangtze rivers.

While the Amazon River dolphin can still be seen swimming throughout their local rivers the Chinese river dolphin appears to have suffered from significant loss due to pollution, construction and aquatic transportation and is considered either extinct or severely diminished.

Physical Appearance and Characteristics

The pink dolphins are marine mammals and share many of the same physical characteristics most mammals have in common such as the need to breathe air, being warm-blooded, giving birth and providing their young with dolphin milk which is produced from the mammary gland.

In order to maintain a stable internal temperature these dolphins have a layer of blubber that keeps their vital organs insulated from external temperature changes in the water and environment.

In terms of size these dolphins appear to represent the largest of the freshwater cetacean species reaching lengths of 5 – 8 ½ ft in length (occasionally more), and weighing between 200 – 500 lbs, depending on location and sex.

Female dolphins are generally larger than their male counterparts by a slight margin and the Chinese river dolphin may have a varying size and weight advantage over the Amazon River dolphin in terms of overall size.

As stated earlier these dolphins generally have a grayish or pink skin tone and are one of the only known species to possess a pink coloring.

Both the amazon river dolphin and Chinese white dolphin are known for their slender bodies, long snouts (which helps them dig for hidden food), short triangular dorsal fin and un-fused necks (which allows them to turn their head 180 degrees).

Both dolphins also appear to have very limited eyesight and primary navigate using a well developed echolocation system that allows them to detect objects in the surrounding area.

The echolocation is so well developed that they can determine an objects size, distance, density, speed, direction and height relative to its own position in the water.

Pink River Dolphin

By doing this they can tell what type of food is nearby and what obstacles lay in their path.

This can be especially useful during the night or when traveling in areas where light is extremely limited.

Diet and Hunting Methods

Because these dolphins can be found living in the fresh waters of the amazon river the foods they consume are largely dependent on the types of aquatic prey that inhabit their local rivers, and since the amazon is known to consume various fish species that are rare in other parts of the world this dolphins prey may include a diet that is rich in piranha and catfish, which are fairly abundant in certain parts of the amazon.

The typical diet for these river dolphins includes small fish, crabs, shrimp, various crustaceans and small turtles.

The pink dolphin is equipped with a long beak that allows it to capture prey that may be hiding in collapsed tree bark, underwater growth vegetation’s, plants and various crevices hidden throughout the riverbanks.

To assist with grabbing their prey these dolphins possess 24 – 34 canonical shaped teeth on each side of their jaw.

They also possess an unfused neck that allows them to turn their head a full 90 degrees.

As stated earlier these dolphins suffer from bad eyesight so they primarily rely on their excellent ability to use echolocation to find potential prey and avoid collision with nearby objects.

By emitting sounds and listening to the echos that return to them the pink dolphin can detect the size, direction speed and density of the objects around it in order to determine whether its food, a wall, a predator or just a floating object.

Dolphin

Migration and Habitat

The Amazon River dolphin can be found in the Amazon, Orinoco and Tocantins rivers while the Chinese river dolphin can be found living in the Yangtze River.

Although the pink amazon river dolphin inhibits the local rivers of the amazon within its designated area they are known to migrate from their local rivers towards other areas of the amazon during certain times of the year.

During the drought season these dolphins tend to stay within their local river habitats as the low waters keep them separated from other groups of river dolphins.

When the rain season comes around and large parts of the amazon begin to flood the pink dolphins can be seen leaving their local habitat and traveling to other destinations where they can meet, greet and mate with other river dolphins.

This may continue for several months until the rain season ends at which point the pink dolphins swim back to their local areas before the water recedes and wait for the next rain season where they can go and explore other parts of the amazon.

In addition to being home to the pink river dolphin the amazon is also known as being one of the most bio-diverse habitats around with 1/3 of the worlds known species inhibiting the amazon and its rivers.

Note: Although we refer to the amazon as having a drought season it is a rain forest and therefore the amazon is never really dry; it rains all year-long. The drought season is simply the time of year when the least rain falls and less of the environment is covered by water.

In terms of where the Chinese white dolphin lives these river dolphins can be found primarily living in the Yangtze river, which is located in China.

Unfortunately not much can be said about the migrating patterns of the endangered/extinct Chinese river dolphin at this time.

Breeding, Reproduction and Lifespan

The average gestation period for these dolphins is estimated to be between 10 – 11 months.

After birth the female dolphin will produce a thick milk which she uses to feed her child for the first several months of birth.

In some cases the mother dolphin may nurse her child for up to 1 ½ years, although some children may stop nursing after 7 – 8 months.

These dolphins generally reach sexual maturity between ages of 4 – 8 at which point they can begin bearing offspring of their own.

While fertile female dolphins may bear a single offspring once every 2 – 3 years; twins are extremely rare.

It is estimated that these dolphins have an average lifespan of 20 – 25 years.

Current Threats

Currently the Amazon river dolphin faces threats from pollution, manmade constructions, fishing and occasional poaching.

River

Due to the inability of researchers and local residents being able to locate the Chinese river dolphin in recent years it is believed that this species is either extinct or extremely rare.

By the 1970’s only a few hundred Chinese river dolphins were known to be left in existence, however by 21st century it became almost impossible to locate these dolphins and no confirmed spotting’s have been recorded in the last several years.

To help prevent additional poaching some countries and locations have made it illegal to hunt these marine mammals and created certain fishing restrictions in an effort to minimize loss and hopefully allow certain populations to recover.

Conservations were also put into place to prevent unnecessary killings and to try to relocate certain dolphins to safer areas where they can live without concern of human threats, both intentional and accidental.

As with other species these dolphins also face threats from natural diseases and in rare cases getting stuck in shallow river banks or between objects in the river during extreme droughts.

In cases where a group of river dolphins may end up getting sick from natural diseases this can have significant affects on small dolphin populations that are having difficulty reproducing offspring.

While these cases are extremely rare they are worth noting as a possible cause for death beyond the realm of possible human considerations and in rare cases can have a moderate to significant consequences.

The Amazon River Dolphin is a group of dolphins that primarily dwell in the South Americas waters, especially in the Amazon river. Also known as the ‘Pink River Dolphin’ or the ‘Boto’, they are not to be confused with the marine pink dolphins. This water mammal is the largest of all the other river dolphin species, and cannot survive in salt water. It is a very distant relative to the sea dolphin, and has a pink to pinkish-grey pigmentation on their bodies, which is one of their primary characteristics, giving them a very unique appearance (and hence their name). The Boto is the only river dolphin that is kept in captivity, mostly in the USA, Venezuela and Europe. However, the rate of mortality is high amongst the captive specimens.

Table of Contents

Amazon River Dolphin Scientific Classification

Animalia
Chordata
Mammalia
Artiodactyla
Iniidae
Inia
Inia geoffrensis
Pink river dolphin predators

Table Of Content

Table of Contents

Scientific Classification

Amazon River Dolphin

Pink River Dolphin Pictures

Animalia
Chordata
Mammalia
Artiodactyla
Iniidae
Inia
Inia geoffrensis
Amazon River Dolphin Pictures

Physical Characteristics

Pink river dolphin habitat

Size: Length of the adult dolphins varies between 2 and 3 meters.

Weight: Can weigh up to 160 kilos.

Skin Color: Color is dependent on their age. While the baby Amazon river dolphins have a dark gray dorsal side, the ventral side is lighter gray. With maturity, the flanks and the ventral side begins turning pink. Pink is predominant in the males. Their colors fade gradually with age, having blue-gray and white tinges all over.

Eyes: Small round eyes but with a strong eyesight.

Beaks: The beaks are pretty long with a strong built adapted to capture prey.

Teeth: The jawline is made of a combination of 24-34 conical and molar-like teeth.

Fins: All fins are same like other dolphins except that they don’t have dorsal fins, but instead, has a hump on the back that gets larger with age.

Lifespan

In the wild, the average life expectancy of these animals is only 33 months. However, in captivity, they have been recorded to have lived between 10 and 30 years.

Distribution

Pink dolphins primarily inhabit the Amazon River in South America, but their range extends to the basins of the Orinoco and the upper Madeira River as well.

Habitat: Where do Pink Amazon River Dolphins live

Botos are generally concentrated below the confluences of the channels. They dwell in the fast flowing, whitewater, clearwater or blackwater rivers of the lowlands. But they are strictly freshwater mammals. They are also found in the lakes, the largest tributaries of the rivers, and seasonally in the flooded rainforests.

Classification of Subspecies

Depending upon their ranges, the dolphins have been classified into the following:

  1. Inia geoffrensis geoffrensis of the Amazon
  2. Inia humboldtiana geoffrensis in the Orinoco
  3. Inia geoffrensis boliviensis from Bolivia

Pink Dolphin Amazon River

Behavior

The Amazon River Dolphins are social and friendly creatures, living since centuries in the Amazon and its tributaries. Usually seen roaming alone, or in pairs during the mating season, these dolphins would hover in groups of 10 to 15 when there is an abundance of prey. Like most other species, these dolphins sleep with one eye open.

Typically, these creatures are slow swimmers, and are primarily diurnal. They are mostly active early in the morning, until late afternoon. They breathe at a shallow angle, displaying their dorsal fins, the beak and the melon all at a time.

Like many other species, the botos are seldom seen leaping above the water surface. However, the Amazon River dolphins are often seen swimming upside down, though the reason is uncertain. It is thought that, the fleshy cheeks of these dolphins act as an obstruction to their bottom vision, for which they tend to turn upside down to get a vision downwards.

Diet: What Do Amazon River Dolphins Eat

Their diet primarily consists of fish, and they depend on healthy fish populations for their survival, feasting upon over 50 types of fish. They also consume shellfish, crabs, crustaceans, and even small turtles.

Video: Feeding the Boto Dolphins

Sounds and Communication

Apart from emitting the sonar (inaudible to humans), these Amazonian dolphins use whistling tones for communication. Researchers say that, this sound has some connection to food. Research has also revealed that, these vocalizations are different in structure to the typical whistles of other dolphin species.

Mating

Before mating, the adult males carry objects like branches, floating vegetation, or hardened clay balls in their mouths to the females to propose for mating. Sexual dimorphism is evident in these creatures, with the males weighing and measuring between 16% and 55% more than females.

Courtship and mating foreplay have also been recorded with the male nibbling the female’s fins. However, if the female is not receptive, the male would react aggressive. The frequency of intercourse in a couple is high, and they have been observed to use at least three different sex positions – lying head to head, lying head to tail, and contacting the womb at right angles.

Baby Pink Amazon River Dolphin

Reproduction and Life Cycle

The boto dolphins breed seasonally, giving birth to the pups between the summer months of May and June. The season of giving birth to the young ones coincide with the flooding season, providing an advantage to the female and its babies. While they stay in the flooded regions longer than the males, until the water level goes down. These areas have enough sources of food to provide the juveniles with enough nutrition they require for growth.

Pink River Dolphin Endangered

The gestation period lasts for about 11 months to 1 year, and in captivity, the birth takes around 4 to 5 hours. During birth, the size (length) of the calf is around 31 inches, with the lactation taking about 1 complete year. The females can again develop offspring after 15 to 36 months. It takes almost 2 to 3 years for the baby dolphins to be adult and independent.

The calves are born between July and September. The period of breastfeeding is relatively long in these mammals, which in turn shows a strong bond between the child and the mother. Also, during this time, the babies learn from the parents and are developed by their care and attention. While the male dolphins attain the age of sexual maturity when they attain the length of about 2 meters, the females sexually mature at about 1.7 meters.

Adaptations

  1. A characteristic that is unique to these dolphins is the presence of stiff hairs on the beak, which are sensory organs aiding them to sense the presence of a prey in the muddy river bottoms.
  2. These water mammals have conical teeth in the front portion of their mouths, which is ideal for holding their prey. The molar teeth situated in the rear end of their mouths are shaped ideally for grinding food before they swallow. This is known as ‘heterodont’ dentition.
  3. Unlike other dolphins having a fused vertebra, this species can freely move their neck on all sides.
  4. Length of the fins allows these mammals to perform a circular movement, and is ideal for exceptional maneuverability during swimming through the flooded forest.
  5. These animals known for their keen eyesight and hearing, which assist them in defending themselves in the deep river basins.
  6. They have large flukes and flippers that make it easy for them to maneuver in the shallow depths of river water.
  7. These dolphins are able to emit audible sonar vibration, which assists in echolocation of their prey.

Pink Amazon River Dolphin Pictures

Threats

The petroleum industry in the Amazon and Orinoco basins pose a threat to the dolphins by means of polluting the aquatic ecosystem where the species is found. In Colombia, the oil pipelines have been blown up by armed groups, causing irreparable pollution.

The raise in contaminant levels of mercury have also caused and increased the total number of recorded deaths among these mammals, especially close to the gold mines, where mercury is used in the process for mining gold.

Predators: What eats an Amazon River Dolphin

These dolphins have few natural predators, but at times, they are hunted down by anacondas, jaguars and caimans. They are also attacked by humans for their skin for leather and for their fat for cooking (and also for leather). They are also caught to be kept captive in aquariums.

Conservation Status

They have not yet been officially declared as threatened or endangered. Because of insufficient data, the IUCN 3.1 has categorized it under their ‘Data Deficient’ list.

Interesting Facts

  • Like many other dolphins, the Amazon dolphins are not acrobatic, and it is difficult to train them.
  • Unfortunately, these dolphins really don’t have a defense.
  • The other four river dolphin species (viz., Indus River Dolphin, Chinese River Dolphin, Franciscana River Dolphin, and Ganges River Dolphin), which are functionally extinct or close to extinction, have their females larger. The opposite holds good for the Amazon River Dolphins.
  • Historically, these animalshave been spared by humans since the local legends and mythology says that, these creatures have special powers.
  • An Amazon river dolphin named Apure lived for forty years at the Duisburg Zoo in Germany.
  • The Botos are not afraid of boats, thus they often suffer from wounds by colliding with them, and even get tangled up in fishing nets.
  • The Amazon River Dolphin Conservation Foundation is a non-profit organization that works to conserve the population of these dolphins and their environment through education, research, and collaboration.
  • Among the five species of river dolphins, the pink dolphins are considered the most intelligent, with the brain capacity being 40% bigger than that of humans.
  • The pink dolphins are known to prey upon the piranhas, the legendary terror of the Amazon.
  • Homosexual behavior in the form of ‘nasal sex’ has been observed in the Amazon River Dolphins, wherein, these dolphins would enter their penises into other males’ or females’ noses (blowholes). This makes them the only animal performing ‘nasal sex’.

Pink Amazon River Dolphins



    • http://www.worldwildlife.org/species/amazon-river-dolphin