The greenish cast of the slothsshaggyfur is caused by symbiotic algae that grow ingrooves running along the length of each of the mammals outer hairs. The sloth hosts thealgae, and the algae return the favour by providingnutritionthat the sloth eitheringestsby licking its fur or absorbs through its skin. Thegrayishgreen colour makes the sloth look just like a clump of dry leaves hanging from abranch the perfect jungle camouflage. And the longer a sloth lives, the greener it gets.
Sloths have a short and flat, head, a snout that is short in length, big round eyes, long tree-tree-climbing legs, a stubby tail and small ears and though some have called themugly, they have the cutest face that looks like they are always smiling just like koala in Australia.
Sloths spend most of the daysleeping. Curling up in a tree notch or hanging from a branch with all four legs closed together, their heads tuck between their front, legs. Peopleseldom see them much move even when they areawake. Only at feeding time, sloths move slowly andcarefully, hand over and through thetreetops, searching for leaves, fruits, and twigs. They even mate and give birth whilesuspendedfrom their long, curved daws. Sometimes a sloth will die hanging upside down from a tree limb and remain so after death, until theydecomposeor are forcibly removed.
Why do sloths have such an unusuallifestyle? Its the strategy they evolved tosurviveas tree-dwellingplant eaters in a place with many predators.
Most domesticherbivores, such as cattle, horse, and sheep, graze all day long. Because they feed on nutrient poorvegetation, they must eat almost constantly. Sloths are alsoclassifiedas herbivores, and their diets are also low innutrition; but rather thanmunchingall day long, they have become masters at conserving energy.
As anyathleteknows, maintaining muscle requires largequantitiesof food energy, far more than a sloths vegetarian diet can provide. Sloths are relativelyinactiveand usually spend most of their day hanging upside down, so they can get by with half as muchmusclemass as similar sizedmammals. Hence, they dont, need to eat too much. In addition, because of heavy muscle sloths weigh far less than other mammals. This makes it possible for them to climb on thin branches high in the tropical forestcanopy, where theycan more easily find food and avoid heftierpredators.
Keeping a high bodytemperaturealso takes energy. Sloths fall this need by maintaining a lower average body temperature than othermammals. Dogs, cats, horses, sheep, and cows all have average body temperatures between about 100 and 103°F, but a slothsaverage body temperature is about 93°F.
Equally important, a sloths body temperaturefluctuateswith the surrounding temperature. Like snakes and frogs which are cold-blooded creatures, a sloths body temperature is highest on warm, sunny days and lowest at night and on rainy days. Sometimes a sloth takes asunbathin the morning to warm up. Then, during thehottesttime of the day, it hides in the shade so it wont overheat. During a 24-hour period, a sloths body temperature may vary as much as10 degrees Fahrenheit. If the body temperature of aperson, a cat, or a dog varies just 5°F, it can be life threatening.
Becauseslothshave difficulty moving over land, they spend most of their time in the trees. They can get just about everything they need high above the forest floor even water,which comes from eatingjuicyleaves and licking up drops of morning dew. Short bursts offeeding followed by long periods ofinactivitymake sloths less vulnerable to large raptors such as harpyeaglesand other carnivores such asocelots. As long as sloths remainperfectly quiet and still, theyre nearly impossible to detect.
At feeding time, a sloth reaches out, grabs anoverheadbranch with its flexible feet, and tugs until the food is within reach of itslong tongue. After pulling the vegetation into its mouth, the sloth clips the leaves with its hard, tough lips and slowlygrindsthem with large, peg-like teeth. A slothdigestsits food just as it does everything else very slowly. People usually digest, their food in about a day, butslothscan take about a month to finish the process. As soon as a slothswallowsa mouthful ofpulverizedplants, the bacteria in its stomach andintestinesbegin breaking down the food. It takes many hours for thebacteriato digest the tough plant material that makes up a sloths diet. Only then can the slothabsorbthe nutrients it needs to five and grow.
So do you have a new understanding about the slow but not lazy animal? Next week we will talk about