The sloths we get in Monteverde are the two-toed type, or it should be two-fingered, because all sloths have three toes. They spend almost all their time alone in the trees, being most ungainly on the ground. Why then, do they come down once a week to pee and poo? No one’s figured it out, especially as it’s pretty risky. That’s when they can get killed by dogs. But even so, they take the time to bury their waste – go figure!
Spanish speakers call them perezosos, meaning lazy, so they seem to also think of them that way, but actually they are the most efficient mammal in the forest. They are largely leaf-powered and weigh about 6kg but ⅔ of their weight can be their stomach contents. They conserve their energy by having the lowest body temperature for a mammal. So in the morning they have to sunbathe on top of the canopy like lizards to get their digestion going. This makes them prime targets for harpy eagles, which can get through 26 sloths in 10 months by feeding them to their young. But luckily for the sloths there are very few harpy eagles left in Costa Rica.
The sloths, however, are pretty common – they only need about 6 acres each, but you don’t see them much. They have specially grooved hair for growing algae which makes them green and difficult to see as they hang out in tangles of vines during the day so they can feel them move if anything’s sneaking up on them. If you’re hiking with a guide and they spot a sloth during the day when they’re pretty still it can be quite hard to even see what it is they are pointing to. Also, they’re fierce and tough if anything did catch them and if they get shot by poachers they keep hanging on and often don’t fall to the ground. But they are suffering from loss of habitat and they can also die of cold in long wet periods. But their most common enemy in Costa Rica is power lines. Still, they can live till they’re 32 in captivity.
The one that was released recently was pregnant and it will take her 11½ months to give birth. The baby will stick around her mom for two years and will be able to have babies of her own at three. There aren’t so many males – I suppose with being pregnant for so long there isn’t much for them to do!
In the lowlands there is another kind of sloth, the three-toed, but they are not closely related to the two-toed. It’s thought that the two adapted to their life in the trees independently.