Animal of the Week November 22, 2010 -- one cuddly sin

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Well, that was a pleasant surprise, there were so many requests to maintain the monkeying that I shall not cancel the emails I shall email, blog, and twitter. But don't forget you can always unsubscribe as directed below if you are sick of my nonsense.

As promised, AOTW is back. AOTW is weekly. AOTW is Bradypus pygmaeus (pigmy three-toed sloth). This slow-living tree-dweller has been singled out by the EDGE (Evolutionary Extinct and Globally Endangered) project as being particularly unique and particularly threatened. Pygmy three-toed sloths live on just one tiny island, Isla Escudo de Veraguas, off the Caribbean coast of Panama, where they live only among the mangrove swamps that encircle it. Estimates suggest there are only three hundred or so pygmy sloths left, their endangerment is largely related to their very limited range, although poaching and habitat destruction by fishermen who sometimes use the island as a camp also threaten the species.

Sloths are fascinating animals of which there are only six living species. The three-toed sloths (four species) and their larger cousins the two-toed sloths (two species) are part of an group of mammals including the anteaters and armadillos that split from the rest of the true (non-marsupial non-monotreme) mammals early in their history. Within this group, the individual species themselves are all distantly related to each other with both three-toed and two-toed sloths likely being descended from separate lineages of ground-dwelling sloths that split many millions of years ago -- so the outward similarity of the two types is likely due to convergent evolution.

Because they spend so much time hanging upside down, sloths' fur grows in the opposite direction to that of other mammals -- if you think how your dog's, cat's, or your own back hair grows largely towards the feet, sloths' fur grows the other way. Perhaps the best known fact about sloths' fur is that it is sometimes green as it is often colonised by algae; sloths welcome this as this helps them blend into the forest making them hard for predators to spot. Because of the algae, sloths fur contains whole tiny ecosystems with moths, flies, beetles, worms and so on all living off the algae. Human hunters tend not to view sloths as prime targets since if shot while they are hanging in a tree, their toes are so well designed to cling on that a dead sloth will remain anchored in the canopy. Sloths' diet of unnutritious leaves means that they have an enormous complicated stomach filled with symbiotic bacteria to enable them to digest huge quantities of food and up to 50% of a sloth's bodyweight can be its stomach contents.

The pygmy three-toed sloth was described by western scientists in 2001. Having been isolated for perhaps 9000 years they have become 40% smaller than their mainland relatives. An example of the island dwarfism that might have created the hominid hobbits of Flores. No joke I am afraid. Maybe next week.
 

 *Photo appreciated in good honour by Bryson Voiron from http://en.wikipedia.org/wiki/Isla_Escudo_de_Veraguas
Peter Hayward
Head Keeper
Animal of the Week

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Animal of the Week November 15, 2010 -- Take that Backshall

Image: Spectacled caiman, St Louis Zoo. Missouri, Robert Lawton

What do the Beck's petrel (Pseudobulweria becki), Sumatran muntjac (Muntiacus montanus), Worcester's buttonquail (Turnix worcesteri), Madagascar serpent eagle (Eutriorchis astur), Madagascar red owl (Tyto soumagnei), possibly the ivory billed woodpecker (Campephilus principalis), and Animal of the Week (Animal septimana [Animal annua more like!]*) all have in common? They were all once thought to be extinct, but after painstaking surveying by naturalists, by happy accidents, or simply due to crushing boredom of the dark winter months, they were rediscovered.

The real inspiration for this resurrection of my long forgotten organ was a clip from the BBC. Now don't get me wrong, I don't wish anyone harm, and I enjoy watching Steve Backshall scaling a sheer cliff face topless as much as (if not more than) the next man, but I do find this new bunch of personality wildlife presenters a little tedious -- the animals are never the star of the show, not if Steve's deltoids are on display. So when the animals strike back it causes me a no little mirth.

There was Steve, traipsing through the pantanal or some such South American wetland in search of an anaconda for his series Deadly 60 in which he tracks down some of the world's most dangerous animals. But it was not the enormous boa, big enough to swallow a human, that Backshall should have been looking out for, no, it was this week's animal of the week, Caiman crocodilus (spectacled caiman). For as he turns around to go home, giving up on his search, Steve's foot hits something hard that he gives a couple of kicks before the hard thing explodes out of the water and has a go of Steve's calf with a jaw of ragged teeth, leaving Steve with a bloodied leg.

Of the alligator family, and part of the larger group of crocodiles, caimans are found throughout tropical Latin America. The spectacled is the most widespread caiman and it is the most common of all the crocodilians. Among the crocodilians, spectacled caimans, named for a ridge between their eyes that gives an impression of spectacles, are not particularly large, reaching a maximum of 2.5 m in length. So Steve's life was never in threat (except maybe due to septicaemia), so I needn't feel too guilty for the joy I take from this clip. I believe Steve recovered quickly and was comparing abs with a jaguar a week later.

Here's the clip: http://news.bbc.co.uk/earth/hi/earth_news/newsid_9166000/9166924.stm

A couple of notes. I mean to resurrect AOTW properly. I missed doing it, and bizarrely quite a few people seem to have missed it. I have signed up to twitter. Imagine that: http://twitter.com/animaloftheweek. I reckon I am going to phase out the email -- most of the addresses are going to bounce back all this time, but if you wish to keep receiving the email, then let me know by emailing back at animal_oftheweek@yahoo.co.uk with the phrase "maintain my monkey" in the subject line.

*Yes, I am sure this is incorrect, my classical education is sadly lacking.