Meet Sammy the Sloth. I painted this cutie right-side up, but in real life, sloths spend most of their lives upside down—even eating, sleeping, and giving birth that way. Although he looks quite huggable, you should think twice before deciding to hug a sloth. Read on to find out why.
🐛 Life grows in their fur
Sloths are home to an entire world of tiny tagalongs. A single sloth can host over 900 insects, including moths, beetles, ticks, and more. Some have even been found with up to 100 moths nestled in their fur! But these bugs aren’t just tagging along—they’re part of a remarkable network of symbiotic relationships.
Take sloth moths, for example. About once a week, the sloth makes a rare and risky descent from the treetops to do its business at the base of a tree. While it’s there, the moths that live in its fur take the opportunity to hop off and lay their eggs in the fresh dung. The larvae grow on the forest floor, then eventually flutter back up to begin the cycle again—returning to the same slow-moving host species they started from.
In return, the moths may help fertilize the algae that grows in sloth fur—thanks to the animal’s slow movements and moisture-rich coat. This greenish tint acts as natural camouflage, helping sloths stay hidden in the leafy canopy. Some scientists even believe sloths may lick the algae while grooming to absorb extra nutrients, though more research is needed.
Together, the sloth, the algae, and the moths form a miniature, tree-dwelling ecosystem—a quiet, leafy partnership that’s as strange as it is beneficial. Just one more reminder that in nature, everything is connected.
They spend almost their entire life in trees
Sloths sleep, eat, mate, and give birth in the canopy. They descend to the ground only about once a week—mainly to poop or, very occasionally, to move to a new tree. Their long claws and curved feet make them excellent climbers, but awkward walkers, so they stay aloft whenever possible.
They’re surprisingly agile swimmers
Sloths can hold their breath for up to 40 minutes—far longer than most mammals their size—and use their long limbs to paddle with surprising grace. They’ve even been known to drop from trees into rivers to travel or escape predators. Turns out, slow and steady swims too.
They have extra neck vertebrae
Despite their short necks, three-toed sloths have nine cervical vertebrae—more than any other mammal. This unique trait allows them to rotate their heads up to 270 degrees, giving them an excellent field of view while barely moving.
They’re among the slowest-moving mammals
A sloth’s top speed on land is about 0.15 miles per hour. But their slow pace is an adaptation to conserve energy and avoid detection by predators. When you’re this slow, staying still is your best defense.
Their hearts beat slower to conserve energy
A resting sloth’s heart rate can drop to about 30 beats per minute, and even lower when they’re stressed or conserving energy. Their entire biology is designed for stillness and efficiency—a perfect match for their treetop lifestyle.
Jackie Foster Art 