We’ve all seen pictures of sloths looking adorable, so we know their fur is light brown. Still, did you know that sloths can turn green when it rains? It’s not a magic trick, and it doesn’t happen after one rainstorm.
Instead, green sloths occur in tropical rainforests where the combination of heat and humidity encourages a whole ecosystem to develop in their fur! Discover why sloths turn green and how this process is beneficial for them.
Why Do Sloths Turn Green?
Sloths live in the rainforests of Central and South America, where they spend most of their time resting and sleeping in the safety of the forest canopy. Not only does this dense layer of forest provide shelter, but it also gives the herbivorous sloth a plentiful supply of food. Still, as the name suggests, rainforests experience high average rainfall, and this abundance of water combined with high humidity causes sloths to turn green.
It’s not the actual sloth that turns green; instead, these hot damp conditions are perfect for algae growth. Moving slowly allows this green (and blue) substance to thrive; still, sloths living in drier conditions do not turn green. And that’s why sloths turn green in the rain.
Are Algae Beneficial to Sloths?
The relationship between algae and sloths is mutually beneficial, and there are some pros for the sloth allowing algae to grow in its fur.
The most significant benefit for the sloth is that the algae provide excellent camouflage and helps it to blend in with the trees. This helps protect the sloth against predators such as eagles, margays, and wildcats. Additionally, the algae can provide an emergency food supply. This isn’t needed most of the time as the canopy provides ample nourishment, but on rare occasions, the herbivorous sloth has been known to eat an insect or two.
And it’s not just insects - the algae are lipid-rich and can nourish sloths as part of a leafy diet. Still, the algae also benefit from a warm, damp environment that allows it to grow and thrive.
And algae aren’t the only organism living in a sloth’s fur; it can house its mini ecosystem with other creatures, such as sloth moths, beetles, and flies. The fur provides protection for small creatures, with its length helping to lock in moisture. And this idyllic spot is a great place for insects to stay and lay their eggs, which creates a life cycle within the sloth’s fur.
In addition, sloths help to fertilize the forest by defecating at the base of trees. Because their digestive process is slow, a sloth’s body can comprise up to 30% waste by the time they go to the toilet, making perfect fertilizer. Also, insects living in the sloth’s fur will jump into the feces to lay their eggs.
These moths act as “nutrient portals,” allowing the fur to become rich in nitrogen, which helps encourage the growth of other algae. Hosting a mini ecosystem of algae and bugs mightn’t sound fun to us. Still, these creatures give and receive positive qualities, meaning the relationship benefits all parties.
Does A Sloth’s Habitat Affect Its Color?
Sloths are a unique mammal species native to the rainforest canopies of Central and South America. The trees where a sloth chooses to make its home must receive a minimum of 250 cm of rainfall per year. This amount of rain encourages various plants to thrive and creates a canopy that is dense enough for sloths to move easily from tree to tree.
The temperature of these tropical rainforests typically ranges between 21 - 30 degrees Celsius, combined with 77-88% humidity. This high temperature and humidity combination allows the area to produce its own rain, with up to 75% of cycles in the forests themselves. With frequent rainfall, the rainforest can receive 1000 cm of rain annually!
Sloths spend so much of their time in the canopy because the dense vegetation provides them with the perfect camouflage, which is why being green comes in handy! Sloths are incredibly slow-moving creatures, often traveling at less than 0.5 m/s (about 1.8 km/h), and they can spend up to 15 hours a day sleeping. They can’t make a getaway from predators, such as jaguars and eagles, so instead, they must seek a safe place to hide.
The denseness of the forest canopy helps to camouflage these slow-moving creatures, increased by their mutually beneficial relationship with algae, whose green hues help sloths to blend in with this lush environment more easily.
Occasionally, a sloth will make its way down from the canopy in search of food or a mate, but most of its life is spent in this dense environment. This is why it’s so important to save the Amazon and similar environments from the threat of deforestation.
Why Do Sloths Move So Slowly?
A sloth’s sluggish pace might appear as slow-motion to you or me. But it is perfectly normal for the sloth, whose extremely low metabolic rate causes them to do everything at this languid pace. They can survive on far less food than the average animal because their digestion takes so much longer, and they only go to the bathroom once every 7 - 10 days.
The reason for this slow metabolism is thanks to evolutionary adaptations. Surviving on a leafy diet, the sloth doesn’t receive many nutrients or calories, so they have to slow their metabolic rate. And their slow pace is also an adaptation to their environment.
Mammals live in some of the most extreme environments in the world, so they have to adapt their bodies with the ability to regulate. However, this thermoregulation takes a good deal of energy. So, animals living in tropical climates - like the sloth - can employ an energy-saving system similar to that of a cold-blooded animal.
Sloths make surprisingly good swimmers and will sometimes drop into the water beneath them, using long arms to create efficient movement. And they’re not entirely defenseless either - they have razor-sharp claws that can harm potential predators.