Three-toed Tree Sloths: an ecosystem case study.

The key word of this story is ecosystem. An ecosystem is a biological community of interacting organisms and their physical environment. Let’s meet the ecosystem.

The organisms that make up the sloth ecosystem are the sloth,

a tree,

dung-eating sloth moths,

and algae.

First, we have a tree. The tree provides a protective home for the sloth. By living in the tree, the sloth can stay away from predators on the ground - like the jaguar for example. The tree also provides food for the sloth.

Sloths eat leaves. Leaves don’t have a lot of nutrients, so sloths get energy very slowly. Because they don’t have much energy, they move slowly. This is a good thing. Predators don’t notice the slow movements of the sloth while it is hiding in the tree.

It takes sloths a whole week to digest enough leaves to need to eliminate waste. When they do need to defecate, they have to climb down their tree. This is a dangerous time for the sloth because it’s on the ground where scary predators might be, so it’s good that it only has to happen once a week.

Once the sloth is on the ground, it eliminates right on the roots of the trees. Excrement from animals includes nitrogen and other elements that help plants grow. That’s why farmers use cow manure on plants - it helps them grow! When the sloth deposits its waste at the bottom of the tree, those nutrients mix in with the soil and it helps the tree grow more leaves for the sloth to eat.

But the tree isn’t the only organism that is happy about the sloth waste. Sloth moths eat sloth dung. These moths even lay their eggs in the sloth excrement - so their babies will have something to eat as they develop into larvae. The baby sloth moths will develop into adult moths and fly up to the treetops in search of a sloth home. That’s right, the sloth is a home for the moths. The moths live in the fur of the sloth so they are assured of a feast once a week.

It get’s even cooler. Once the moths have digested their stinky dinner, they need to eliminate waste too. They do that right in the sloth’s fur. Which sounds kind of annoying for the poor sloth, but it actually works out in it’s favor. Moth excrement has nutrients that are good for plants just like the sloth excrement. When the moth excrement is combined with water that gets trapped in the sloth’s fur, it grows algae. This algae is the 4th organism in the sloth ecosystem. It helps camoflauge the sloth, making it blend in with the tree so that predators from above - hawks, eagles, and other birds of prey - don’t see the sloth. The sloth may also eat this algae, but scientists aren’t sure about that yet.

Each member of this ecosystem has a role to play in helping the other members thrive. The sloth helps the tree by providing nutrients and the tree helps the sloth by providing shelter and nutrients. The sloth helps the moth by providing shelter and nutrients and the moth helps the sloth by providing nutrients. The moth provides nutrients for the algae and the algae provides camouflage and perhaps nutrients for the sloth. If any one member of the ecosystem were to go away, all of the other members would be hurt.