View Full Version : Sloths Are Better at Adapting Than We Ever Gave Them Credit For

01-18-2019, 02:57 PM

Unless you live in the tropical rainforests of South or Central America, most of the sloths you'll encounter will be two-toed sloths (Choloepus sp.). This is because they are able to eat quite a varied diet and are therefore relatively easy to keep in captivity.
Their relatives, the three-toed sloths (Bradypus sp.), on the other hand, have a very restricted diet, subsisting solely on Cecropia: a group of fast-growing tree species with soft wood and large, juicy leaves.
Or so it has always been thought. A paper published this week by the Royal Society gives quite a different picture of the lifestyle of three-toed sloths.
The authors of the paper looked at how the availability of different tree species, including those of the genus Cecropia, affected the survival and reproduction rates of sloths.
Given that these trees are the sloths' favourite food, this specialist sloth species might be expected to spend most of its time in them. However, the authors found that at certain life stages, sloths may desert their favoured tree for other species.
Density of Cecropia is critical to the survival and reproductive success of adults, especially the males, but was not correlated with survival rates of juveniles.
The authors attribute the differing importance of Cecropia at different life stages to the shape and growth habits of the tree, and they give a detailed analysis of its effects.
Because Cecropia species grow fast and produce lots of leaves with few chemical defences rather than a few leaves that are defended by a lot of toxins, there are always young, palatable, easily-digestible leaves available for adult sloths.
The leaves also contain essential nutrients that keep sloths in good health, which would suggest that juveniles should also favour them.
Cecropia foliage consists of a fan of large leaves at the end of a long stem or branch with no other leaves on it, giving it an "open structure".
This means the tree does not make a good hiding place for young sloths, who may be more vulnerable than adults to predators like jaguars or eagles, even though they are quite well camouflaged.
Similarly, mothers with babies may choose trees that have a thicker canopy as their maternity ward, moving back to the Cecropia tree when the baby is older.
This open structure is important when it comes to mating.
Sloths are solitary creatures with extremely poor vision and, when the time is right, they need to find a mate from a widely dispersed population.

Sloths Are Better at Adapting Than We Ever Gave Them Credit For (LINK) (https://www.sciencealert.com/sloths-are-better-at-adapting-than-we-ever-gave-them-credit-for)

#include [ std-disclaimer ]