General facts About Dolphins.
Humans rule the food chain because of their heightened innovation, empathy, problem-solving, and sense of self. But surprisingly, these qualities are also found in the behaviour of Dolphins! These magnificent creatures belong to the Cetacean family and are prized for their “Cetacean Intelligence”.
This intelligence belongs to dolphins, porpoises, and whales. Among many capabilities, they have strong emotional intelligence and tactical problem-solving. Within this family there are 49 species, which includes 4 species of river dolphin: the Amazon River Dolphin. The Baiji – now extinct. La Plata Dolphin. The South Asian River Dolphin.
These river dolphins share similar characteristics to their saltwater cousins, because all dolphins originated in the ocean. River Dolphins have the highest risk for extinction of all, because they have a smaller habitat where they must compete for resources. Many humans live off the Amazon River alongside these dolphins, making habitat loss from human activity their greatest threat.
The Amazon River Dolphin, also known as the Boto, is a pink dolphin that lives exclusively in freshwater. It has a long, slim beak with 35 teeth fused together. The top of its head is the “melon”, which is used by this Dolphin for echolocation. It is said to be the most intelligent Dolphin, with 40% more brain capacity than humans! We know a lot about these Dolphins because they are inquisitive and confident around people. Throughout the years, they have been seen as sacred by Amazonian tribes. Due to this respect, they have been naturally conserved. Their habitat, however, is subject to future destruction as competition for resources increase.
The Amazon River Dolphin: Out of the Blue!
What is the size, weight & colour of the Boto?
These are the largest of the river dolphin family. Males grow to an average length of 2.3 meters and weigh 150kgs. Females are smaller, reaching lengths of 2 meters and 100kgs.
This size combined with their impressive pale pink hue makes for easy sightseeing! The Boto is born grey, but depending on lifestyle and diet it can reach a vibrant pale pink hue. Much like humans, this pink can also deepen when they are excited, much like blushing. The pigments in their skin can also appear mottled. This is due to exposure to sunlight, like freckles on humans.
What type of vision does the Boto have, and what sounds do they make?
The Amazon River Dolphin has exceptional eyesight despite the small size of them. They need this keen vision to spot prey in stirred up riverbeds. Despite this, our friend relies more on echolocation to find prey. The 10 calls it uses in echolocation can be clearly heard by human ears. They come across as various tones on high pitched “squeaking”.
Are there any special or unique physical attributes?
Unlike their saltwater cousins, this river dolphin has unfused vertebrae on its neck, allowing them to turn their head 180 degrees. They need this advantage to maneuver around rocks, trees, and other obstacles in the river. Instead of a dorsal fin, they are equipped with a dorsal ridge, which keeps their bodies streamlined and agile.
They also have a few tricks up their sleeve for seamless swimming: including back-paddling with one fin for sharp turns, and swimming upside down. Ever-social creatures, they will often swim in packs of 3, so they can cover more ground in search of food.
How fast is the Boto?
Unlike Dolphins in the ocean, the Boto has less ground to cover in search of food. Much like other species of river fish, they are slow movers drifting at 3kmh. They have to potential to reach up to 22kmh in short bursts, but this is rarely necessary. Their environment has a natural flow and current which helps them keep a leisurely pace.
What are their Migration Routes?
The Amazon River Dolphin has a special seasonal migration from river to land – without them having to leave the water. The spring in South America, known as the “wet season”, brings large quantities of rainfall. This rainfall floods thousands of miles of the Amazon Rainforest, creating a sea amongst the trees. During this time females will retreat into these waters to evade aggressive males. Once this wet season is over the water retreats back, reuniting the dolphins for mating season.
How do they hunt, and what do they eat?
The Boto is an apex predator, which allows them to eat all varieties of fish in the Amazon River. They must consume 2.5% of their body weight in a day to maintain their energy. The most common meal for our friends is Piranha, alongside turtles, squids, and crabs. Their powerful jaw is mainly used to hold prey, but they typically swallow without chewing and regurgitate bones later. They have been seen primarily hunting in groups.
What are their natural enemies?
Apart from human activity, the Boto needs to watch for Jaguars, Caimans, and large snakes. These predators will usually hunt smaller, easier prey, especially since our friends rarely swim alone, even in their infancy.
Where do they live?
These beautiful friends can be found throughout the Amazon and Orinoco river basins, spanning across Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela.
All about Reproduction.
Sexual maturity varies depending on the size of the Boto. Females are sexually mature at 1.7m in length, while males are sexually mature at 2m. After a 13-month gestation period, the female Boto will retreat into flooded forests to give birth in the wet season (May – June). This allows her to protect herself and her calf from aggressive males. The calf can remain dependent on its mother for up to 3 years! Unlike many animals, the lactation period lasts a full year, which is observed to create a strong bond between mother and calf. The care and attention these calves are given in their early life helps their development and overall longevity.
What is their lifespan?
The longest living Amazonian River Dolphin on record is 40 years. Their full lifespan is uncertain among scientists. It can range anywhere between 10 and 30 years.
The Boto has yet to reach extinction due to indigenous mythology protecting them. In South American culture, it is bad luck to consume the flesh of a Dolphin, as they are considered sacred guardians of the river. Many myths are supported by true stories of Boto rescuing drowning people and bringing them to shore. It is also believed that if you swim with Boto, they will carry you to an underwater city.
What threats do the Boto face?
While mythology has largely protected the Boto from aggressive hunting from humans, they are still often caught for Catfish bait. They are also persecuted by fishermen for hunting valuable river fish. Many Botos fall prey to irresponsible fishing equipment in search of food by riverbanks. On top of this direct conflict, the destruction of the Amazon Rainforest is the largest threat to our friends. With river dams and clear-cutting increasing throughout the Amazon, these Dolphins will be stripped of important habitats over time.
Endangered Ranking – IUCN.
Published on their “Red List” in 2018, the IUCN stated that the Amazon River Dolphin is critically endangered. It is difficult to make an accurate assessment due to their populations being spread across various countries. But recent estimates state there are 9,000 Botos left.
Why are they endangered?
Their population is falling fast due to the rise in the popularity of Dolphin meat for catfishing. They are also cursed with slow reproductive rates, with one calf being born every few years. Without conservation of the Amazon Rainforest, habitat loss will increase over time and strip these Dolphins of their hunting and breeding grounds. All of these factors have contributed to their endangered ranking and will continue to contribute to their falling populations.
Why should you care?
The Amazon River Dolphin has an important place in the food chain. As an apex predator, it stabilizes the populations of smaller fish, which affects the overall health of the ecosystem of the Amazon River. Without the Amazon River Dolphin, the health of the river would decrease over time, which would impact the surrounding forest. The Amazon Rainforest is important to the air quality of the planet, as it removes Carbon Dioxide from the air and combats global warming. Everything in nature is connected, and the extinction of one animal can vastly contribute to ecological collapse over time.
What can you do to help?
- Ethical Consumption: Ensure catfish meat is from responsible sources that refuse to fish with Dolphin meat – or refuse to consume Catfish entirely. This trade has created a demand for River Dolphin meat that did not exist before.
- Spread the word! Talk to family members and friends about what they’re doing to help the cause. Inform people on ways they can help protect the Amazon Rainforest as a habitat. With an increased demand for conservation, we can create a safe future for the Boto.
- Get Involved: Lastly, spend time signing petitions and getting involved in online spaces. Bringing widespread attention to the deforestation of the Amazon Rainforest is paramount.
If there is a public demand for change, then change will come. With everyone’s help, we can create new standards for the Amazon and all of its inhabitants! With safer habitats, we will hopefully see Amazon River Dolphin populations stabilize.