Lazy leaf. What is special about the slow-moving mammals of Central and South America
In the tropical forests of Central and South America live sloths — animals the size of a large cat, which fully justifies its name. They slowly “crawl” through the trees, and their extinct relatives, megaterio, reaching the size of an elephant, slowly moved across the ground.
Sloths belong to the suborder Folivora, Latin leaf beetles. They do feed on the leaves and woody shoots, and this low-calorie diet determined their “lazy” lifestyle and the need to save energy. Sloths have a low metabolic rate and low body temperature.
Muscles they are much less than other animals of the same size, so sloths are slow and move only if necessary. To get to the food, they often don’t have anywhere to crawl: lazy long legs, which he reaches for a nearby leaf. Internal processes in the animals too “lazy” — slow blood circulation and rare breathing, the digestive process can last up to a month.
Sloths are perfectly adapted to life in the trees. As they hang from the branches back downward, the wool they grow is “wrong”, in the direction from belly to back, so that the “top” and “giants” are on the belly. So the animal is better protected from heavy rains: the water, flowing down downwards, practically does not penetrate under the hair.
Internal organs are also adapted to the inverted position of the liver is shifted to the back and under stomach. So big and heavy body is no pressure neither digestive organs nor the heart and lungs. Most of my life sloths spend on a tree branch caught in the powerful curved claws. In this position they sleep, and eat. “Processed” leaves of one tree, they move on.
Slowness of sloths is a plus — immobility protects them from predators: jaguars, ocelots and hawks the harpies. In addition, the sloths got camouflage: they have wool live microscopic algae, which gives it a greenish hue, so that the animals almost blend in with the foliage.
In addition to protection, algae feed Supplement to the meager diet of sloths, unlike leaves, they are easy to digest and many nutrients. In addition to algae sloths carry on many insects, including the other symbionts butterfly-moth of the genus Cryptoses that provide “protective” algae sloths additional nutrients.
If on the trees the animals feel comfortable, on the ground that they are almost helpless. Paws sloths are not designed for walking, so they are forced to move on land by crawling, clinging paws for the grass and pulling.
Therefore, tree sloths trying to descend as little as possible, only in search of food or a couple, as well as, every few days to urinate and to empty the bowel. This is due to the fact that the bladder of the sloth can hold up to a liter of fluid and stretch to the diaphragm. Why would they come down to earth for the sake of hygiene, it is not entirely clear. Possible to provide their symbionts — the butterfly-moth — a suitable environment for breeding. The female moth lays eggs in the feces of sloths, and the larvae develop in this medium. After turning into a butterfly moth fly in search of a sloth and a couple in his fur.
Surprisingly, slow-moving sloths are great swimmers — they can swim across the river, and the prehistoric relatives of sloths, megaterio, sailed from Central America right up to the Antilles (which are at a distance from 77 to 200 kilometers from the mainland).
Currently the planet is inhabited by two families of sloths — dogplie (Megalonychidae) and three-toed (Bradypodidae) sloths. Actually on my feet and those in the other three fingers, but in the hands dvuhpolnyh sloths two finger and three-finger three.
But even 10-12 thousand years ago in the Americas was inhabited by giant sloths, who, like modern, eating leaves, but lived on earth. The largest of them, megaterio and remotely was the size of an elephant. Their height reached six meters and weigh 3-4 tons.
Giant sloths eating trees, becoming on back paws and leaning on the tail. North America was inhabited by smaller, three-meter sloths — megalonissi.
About the reasons for the extinction of giant sloths, scientists still argue. According to one version, they destroyed the people who came to America shortly before their disappearance. Huge slow beasts were relatively easy prey, to the same hypothesis is confirmed by the fact that in the Antilles sloths became extinct much later than on the mainland (about five thousand years ago), after the appearance of the people there. Other researchers believe that the role played by climate change — the disappearance of the habitats of sloths, coupled with hunting led to their extinction. .
Ekaterina Rusakova