Why are sloths so slow?

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Why are sloths so slow?

In: Biology

They eat tough to digest low nutrition food. As such they digest slowly and don’t get a ton of nutrients back. They’ve evolved to live slower as a way to balance that out.

There is a STUFF YOU SHOULD KNOW podcast about Sloths. The episode is called “How Sloths Work”… If you want to know more about them.

One of the great struggles of life in the wild is obtaining enough energy to survive. For a lot of animals, finding something to eat is dangerous. For some, it involves leaving the safety of their burrows to risk predation. For others, it means risking injury chasing down a prey animal that might put up a fight.

Often scarcity is an issue. Maybe nothing lands in your web, or all the prey animals are too healthy to outrun. There’s been a bad season and there’s not many fruits or nuts to go around.

There are many strategies for dealing with this. Some animals eat something that might not be very nutritious but at least it’s plentiful, like grass. Other animals evolved digestive systems that can digest almost anything so they can eat a wide variety of foods.

Sloths evolved to be extremely energy efficient and as a result, they don’t need to eat much.

* They have a very slow metabolism, which means they don’t move much, and when they do they move slowly. But it uses up very little energy.
* They hang upside down because this takes virtually no strength expenditure on their part. The hooked claws let them hang from branches without the need to expend energy to grip.
* Their fur actually grows in the opposite direction from most mammals. Instead of growing from their back in the direction of their toes, it grows in the opposite direction. This way rain still flows off them while hanging upside down.
* Their body temperature is very low for a mammal, again little energy is wasted here keeping their body temperature up. They don’t plan on needing fast responses anyway.

And an animal like that obviously isn’t going to flee quickly or put up a good fight. So they have even more adaptations for dealing with that.

* Sloths are very lightweight for their size. This lets them climb high in the trees on the thinnest branches where many of their predators are too heavy to follow.
* Sloth’s fur contains a whole ecosystem of fungi, moulds, mosses and even small invertebrate animals. It doesn’t just camouflage sloths visually, they pretty much have no scent of their own and basically smell like their environment. The shaggy fur also breaks up the outline of the sloth.
* And many predators are attracted to motion. The easiest way to spot prey is to notice their movement against the background. The slow and jerky movement of the sloth combined with the fact that it has no clear outline or scent means they’re nearly invisible to predators most of the time.
* Sloths are so efficient that even peeing and pooping is something they only do once every few days.

Essentially sloths are extreme specialists and their niche is energy conservation. The less they need and the less they do, the fewer risks they have to take to survive.

They only eat one kind of leaf and it’s very low in calories. They evolved to conserve energy in a pretty extreme way. They’re also pretty stupid. They don’t recognize any other food, even the same leaves unless they are on a tree.

They have a terrible diet, eating pretty much only leaves which give them too little energy. Also compared to other animals, sloths have half as much muscle mass.

All other animals are like “i got to find food so i got to go fast and to be fast ima need more food” and the sloth is like “fuck that give me 200kcal ima go sleep”