Saturday, December 8, 2007

Mermaids of the Amazon

Last month, I mentioned Marc van Roosmalen in my post about his recent discovery of the giant peccary, but there's more to say about this Dutch biologist.

First, in addition to the giant peccary and a whole new genus of monkeys, earlier in our young century van Roosmalen also uncovered a new species of small, freshwater manatees living in the Brazilian rainforest.

Dwarf Manatee

The dwarf manatee is only about 4.25 feet in length, and it has an obsidian hide with a white spot on its underbelly. Members of this new species live in shallow, fast-flowing, clear waters where they graze on aquatic grasses and other non-floating plants, and their habitat is limited to the Arauanzinho river -- a 120 km tributary of the Rio Aripuanã. Hey, that's right near the giant peccary's hood! Van Roosmalen gives the species, known to the locals as pretinho ("little black fellow"), the scientific name trichechus bernhardi. Thus he named the dwarf manatee after HRH the late Prince Bernhard of the Netherlands just as he did with the titi monkey, callicebus bernhardi. Van Roosmalen says this new species must be considered on the verge of extinction given that the only viable population is restricted to a single small river.

Amazonian Manatee

There is another species of manatee that can be found in the freshwaters of the Amazon rainforest, the trichechus ingunius (called peixe-boi comum, or "common cow-fish", by Brazilians). These manatees are larger and inhabit blackwater and whitewater lakes and calm rivers with low visibility. There they subsist mainly on floating vegetation and submerged foliage. Their hide is also dark grey as opposed to the black dwarf manatee.

Other manatees

The only other extant species of manatee are the West Indian and West African Manatee. The West Indian Manatee can be found in the coastal waters of the Gulf of Mexico and the Atlantic. Because of the manatees' low body temperature they usually stay in the tropics, but in the summer they have been spotted as far north as Rhode Island. The mysterious West African Manatee is very rarely seen which probably means that there aren't that many of them.

Sirenians

Along with the dugong, manatees comprise the order of aquatic mammals called sirenians. Dugongs differ from manatees in that they have a fluked tail like a dolphin as opposed to manatees' paddle-like tails, and they are found in the Indian and Pacific Oceans. The name Sirenian follows the widely held belief that these were the creatures that delusional seamen of yore mistook for plump mermaids (interestingly enough, in Italian and Spanish the word sirena is used both for the Odyssey's sirens and for Hans Christian Anderson's mermaids thus connoting that these mythical creatures were one and the same). In the wikipedia article on mermaids, it is noted that, although they don't look much like beautiful women, in centuries past people might have imagined that sirenians were humanoid creatures given that females cradle their babies between their flippers and nurse them just like human women.

Another species of sirenians which is now extinct was discovered in the Bering sea in the mid-1700s. It was named Steller's seacow after the species' discoverer. When Georg Steller first wrote about the species in 1741, there population is thought to have numbered around 1,500, but in less than 30 years they were hunted to extinction. People used their hide to make boats and their fat to make lamps. They were also hunted for their meat (which probably tasted more like beef than fish given that they are herbivorous mammals -- one more reason they were called seacows).

Today all surviving species of sirenians are considered threatened if not endangered. Manatees and dugongs are occasionally killed by crocodiles or sharks, but the only serious danger to their survival comes from humans.


Dwarf manatee photo (c) Marc van Roosmalen, Amazonian manatee photo (c) Sirenian International, Inc.

1 comment:

Josie said...

when we first moved to Florida, one of my requirements was to see a manatee. little did i know how easy that would be! we kayak on the St. Mark's natural spring and there are always a handful of them out. it's sad to see their scars caused by boat propellers tho. but they are very gentle :)