Did you know you could encounter free dolphins outside of the ocean? Did you know these dolphins are pink and have whiskers?! This month’s we travel deep into the Amazon’s (and the Orinoco) forest and river basins, where we find the elusive Amazon River Dolphin or Boto (Inia geoffrensis).
Just Around the River Bend…
The boto is a freshwater cetacean. It typically inhabits rivers all through Colombia, Ecuador, northern Peru, Brazil, and Bolivia. During the rainy season every spring, thousands of square miles of rainforest are flooded, extending their habitat well within the forest.
As a result, these waters are quite murky, but the boto has adapted to its surroundings. Firstly though they have rather small eyes, they can see rather well, even in their murky habitat. Plus, like their other toothed whale counterparts, they too use echolocation to find prey. In addition to that, they have a really long snout covered in little whiskers. This long snout helps them shift through the mud. Scientists say the whiskers are similar to seals’ whiskers which help them detect prey.
The Boto typically feeds on crustaceans found on the river bed or small fish that whiz past them. They have large paddle-like pectoral fins with equally large flukes that help them steer in shallow waters. A unique characteristic that rivers dolphins have, that other dolphins don’t, is an unfused neck vertebra. This allows them to have more maneuverability and even turn their neck up to 90 degrees!
“On Wednesdays We Wear Pink”
The most striking characteristic of the boto is the fact they are pink! The Boto is initially born grey. As it matures, it gets pinker or pinkish-grey. Typically it starts on the ventral, or belly side, and then works its way up the body’s sides. Males tend to be pinker than females. This could be due to the fact that males tend to show more aggression towards one another. But the “pinkness” of the boto also depends on the individual dolphin and where it might be located in the Amazon. Apart from their rare jumping picture posted earlier, they tend to barely surface. They do not have distinct dorsal fins either. Therefore it is difficult for scientists to create population estimates.
Males tend to be larger in size as well ranging from 6 feet (2.5 m) to 9 feet (2.7 m) for males. Females tend to be smaller: around 6 feet (1.8 m) to 8 feet (2.4 m). Botos can be as heavy as 350 pounds (160 kg). The calves are significantly smaller averaging about 32 inches long at birth (80 cm) and weigh about 15 pounds (6.8 kg).
Threats and Foklore
The only known threats to the Boto are humans. Botos are typically used as catfish bait. They can even be used for leather. Bycatch from gillnet fishing in another issue and some fishermen consider them as competition for fish. As of 2019, Colombia and a few other South American countries are planning to build hydropower plants in the Amazon. This could lead to unknown consequences for the overall delicate ecosystem that has already been plagued with deforestation. The botos will further be separated from each other, potentially weakening the species’ gene pool. Scientists are having debates already on if this species should be broken down into subspecies. More data should be gathered before anything is decided.
A few of you might have watched “The Wild Thornberry’s” growing up; I know I did. There is one episode I remember distinctly that explained the folklore that the Traditional Amazonians believe about the Boto. Though they cleaned it up for the children’s show, they did a pretty good job explaining it. The Amazonians believed that the Boto has the ability to transform itself into a human. It can walk and interact with humans, covering its blowhole with a hat. It has been known to seduce young girls as well causing unexpected pregnancies. If one would kill the boto, it was considered a big taboo. That person would have incredibly bad luck and misfortune the rest of their lives…
Thanks for Reading!
Here is a short documentary from BBC earth that I think gives a better general overview of the Boto. Enjoy!
- National Geographic’s article and video of the Boto
- American Cetacean Society: Boto
- More detailed Story of the Boto Folklore
- Hydropower Plants
- Marine Mammal Encyclopedia: Iniidae
We hope you learned a thing or two about the pink Amazon river dolphin. As we said in this post, scientists need more data to assess the health of boto populations. Maybe you could become the next boto expert?
Make sure to check our other Whale of the month posts here.
Naomi Mathew is a PhD student at University of Louisiana at Lafayette. She works on bioacoustics in marine mammals from the Gulf of Mexico. She is the co-founder of Whale Scientists. You can read more about her here