(Photo: Wikimedia Commons/Silvio Batista Piotto Junior)
Pink River Dolphin: 5 Fun Facts About the Freshwater Cetacean With the Largest Bodies and Brain

Pink river dolphins are rare and they are mesmerizing. Due to their unusual color for their kind -- as most dolphins are colored white, pearl to darker shades of brown, gray, blue, and black, depending on the species -- they are considered mythical creatures by some and have been revered.

Apart from that, these dolphins are talented. Here are some of its key facts.

1. They Are The Largest Species of River Dolphin

River dolphins exist throughout the Indian subcontinent and in China, but the Amazon River dolphin (Pink Dolphin) is the biggest species. Males can weigh over 450 pounds and are 50% larger than females.

"This freshwater cetacean is the largest species of river dolphin," said biologist and author Helen Pilcher.

Since they are the largest, they have the largest bodies and brains. They are also the smartest out of the five freshwater species.

When fully developed, a dolphin can reach a length of 9 feet (2.7 meters), a weight of 400 pounds (181 kilograms), and a lifespan of 30 years. Out of all the toothed whales, especially in the rainy season, their food is the most varied, containing over 53 species, including piranhas. Additionally, compared to humans, they have 40% larger brains than average.

2. Pink Color Is Due to Genetic, Diet and Environment Factors

The Amazon River dolphin is distinguished from other species by its distinct pinkish coloring. Although the precise cause is unknown, a mix of environmental, dietary, and genetic variables are thought to be responsible for its shade.

Their diet, which is rich in carotenoids-an organic pigment found in the fish and crustaceans they eat-is one factor contributing to their pink coloring. Since carotenoids are known to contribute to the pink or orange color of several fish, reptiles, and birds (like flamingos), the exact mechanism likely causes the dolphins' pink pigmentation. Carotenoids, the most abundant pigments in nature, are also found in certain types of fungi.

Furthermore, environmental and hereditary factors may contribute to its shade. According to certain research, the pink coloration may be connected to skin thickness, influencing the amount of blood that appears through the skin. It is also feasible that hormones, stress, or other elements affect the pink river dolphin's color.

"They are born grey and acquire their pink color with age. Their final hue is influenced by many things, including behavior, diet, and how close their capillaries are to the skin," Pilcher said about the pink river dolphins' color.

3. They Can Change Colors

The pink color of Amazon pink river dolphins is well-known, but it wasn't always this way. Dolphins are gray at birth and gradually turn pink as they mature. The male dolphin's coloration is notably pinker than that of the female; this difference in pigment is believed to result from scar tissue from aggressive games or fighting over territory. Brighter pinks draw greater attention from the females, but other factors, including behavior, capillary placement, food, and sunshine exposure, can also affect their final hue. These river dolphins can have completely flamingo pink or primarily gray markings with some pink dots. Like humans, dolphins can blush a brighter pink when they're happy!

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4. They Are Elusive and Secretive But Super Agile

The pink river dolphin is frequently spotted by itself or in small groups of two to four people, usually consisting of the mother and her young. The riverine waters are frequently dark and full of sediment, making counting them difficult. Another is that they often only stick their heads out of the water, not making a conscious effort to be noticed. Their quiet and secretive nature contributes to their mythological nature, and they spend much time underwater.

However, they are very flexible. They can cross obstacles like boulders and tree trunks by turning their heads 90 degrees. Additionally, they can turn more precisely by swimming forward with one flipper and paddling backward with the other. They frequently swim back to improve their vision of the river's bottom.

Despite having small eyes, they have exceptional underwater and overhead vision, and their keen echolocation skills allow them to easily navigate the murky waters of the Amazon to find their prey.

5. They Are Considered Mythical Creatures

Many stories in South American folklore revolve around the Amazon pink river dolphin; not all are positive. According to one such tradition, at night, the dolphins transform into attractive males called "boto encantado" who entice and impregnate women. There is a local fear of swimming alone or near the ocean between nightfall and morning because another story says dolphins can carry you away to a beautiful underwater city if you go swimming alone. In addition, many think of them as the protectors of the Amazon manatees; thus, anyone hoping to view one must first make peace with the pink dolphin. Injuring dolphins is said to bring ill luck while eating them is said to get even worse luck.

Amazon pink river dolphins are categorized as "endangered" by the IUCN Red List in 2018.

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