Two-Toed Sloths in Maryland

Built for hanging around

The coat. A sloth’s fur grows the opposite way from most mammals’, parting along the belly and running toward the back, so that rain runs off an animal that is hanging upside-down. It has a short, fine undercoat topped with longer, coarse guard hairs. In the humid forest, algae grows in grooves on those hairs and turns the coat faintly green, camouflage that can make a single sloth its own small ecosystem, home to moths, beetles and other tiny creatures living in its fur.

The grip. The long, curved claws are hooks, not fingers. A sloth hangs from them without spending any muscle effort at all, which is why a sleeping sloth does not fall out of its tree. On the ground the same claws make walking awkward, so a sloth on the forest floor drags itself along and is at its most vulnerable.

The neck. Nearly every mammal, from a mouse to a giraffe, has seven neck vertebrae. Two-toed sloths have between five and seven, one of the very few exceptions, and can turn their heads a long way in either direction without moving the rest of their body.

The engine. Sloths are famous for moving slowly, and with good reason. They keep an unusually low and variable body temperature, between about 86 and 93°F, which drops further in cool or wet weather or when the animal is resting. That slow metabolism lets them conserve enormous amounts of energy, enough that they can hang motionless, and even eat, without expending much effort at all.

Hooked claws, a long neck and a coat that parts along the belly: a body designed for life upside-down.

Indoors on a cool day, coming over to look at the camera.

Seeing them at Plumpton Park Zoo

Sloths sleep for much of the day, so the trick is patience: find one, then give it a minute. Look for a slow reach of one long arm, the head turning to watch you, or the unhurried business of a meal. Because they live at a pace of their own, the sloths are also one of the animals children most enjoy simply standing and watching.

They are a tropical animal, so on cold days they stay in their heated indoor quarters. Warm days are the best days to see them out on the branches and ropes.

Two-toed sloths and conservation

Linnaeus’s two-toed sloth is listed as Least Concern by the IUCN, because it lives across a large part of the Amazon basin and tolerates some disturbance. That is not the same as safe. The pressures on it are the ones facing the whole Amazon: forest cleared for large-scale agriculture, logging and mining, wildfires that kill sloths outright or leave them without trees, and an illegal pet trade that takes sloths from the wild across much of their range.

The pet trade deserves a word. Sloths photograph well and look calm when held, but a wild sloth handled by a tourist is a stressed animal, and most sloths taken for the trade die within months. If you love sloths, the way to help is to support forest protection in South America and to never pay to hold one.