River Dolphins: A Glance At Freshwater Cetaceans
Amazon River Dolphin
This particular freshwater dwelling mammal persists in the Orinoco, Amazon and Araguaia/Tocantins River systems of Brazil, Peru, Bolivia, Ecuador, Colombia, and Venezuela. They’re not considered endangered but at the same time no one is too sure how many of them there are.
Also known as the boto, this river dolphin is the largest freshwater cetacean in the known Universe. The long-beaked boto has non-fused vertebrae giving it much more flexibility than your average salt loving dolphin, this assists them in navigating through submerged forests. Their colour can range from dishwater grey through to carnation pink, which is nice.
The Amazon River dolphin competes with humans for the same fish species, this causes a spot of bother between tribes people and the watery mammals. The species is protected but that doesn’t stop them getting caught in the nets, the humans get jazzed off about it too because they ruin their nets and they don’t even get the benefit of using the beast they caught. Some fishermen do kill the dolphins of course, and they use them as bait to catch the fish they are legally allowed to eat.
Mekong Irrawaddy Dolphin
I saved the best for last, or the weirdest looking at the very least. I had the pleasure of seeing one of these Mekong dolphins for myself whilst visiting the Mekong delta in Laos, admittedly it was about a mile away, but it still counts.
Unlike the rest of the freshwater dolphins we’ve seen today these guys pretty much have no snout at all, their heads sort of resemble bowling balls don’t they? This odd visage makes sense when you learn that they’re more closely related to killer whales than other dolphins.
The Irrawaddy dolphin moves at a relaxed pace and is thought to capture fish by sucking them into its mouth like a Dyson.
Humans seem to have had a mutually useful relationship with the Irrawaddy for centuries. Fishermen in India remember a time when they would literally call out to the dolphin asking them to herd fish into their nets. Similar stories are reported in Burma so there must be something in it, the dolphins would be rewarded with fish for their services.
An 1879 report indicated legal claims were frequently brought into native courts by fishermen who wished to recover a share of the fish from the nets of a rival fisherman which the plaintiff’s dolphin was claimed to have helped fill.
The Irrawady has a pretty large hunting ground that extends from the Bay of Bengal to New Guinea and the Philippines but there’s not a thriving population, they’re pretty rare and on the decline. Technically they aren’t considered a true river dolphin because they mainly stick to brackish water. I’ve still included them here though because they look so odd.
I’ll leave you with this picture of a finless freshwater porpoise. They’re the only species of porpoise that lives in fresh water and they are super ultra endangered. Each individual that dies is another nail in the coffin of the freshwater porpoise. This photo should NOT be funny, but the corpse’s wry smile tickled me… it’s like he’s thinking “don’t worry, I’ll let her cry for a few more minutes and then I’ll tell her I’m only messing”…
