Sloths possess surprising strength — it is extremely difficult to detach them from a tree in an emergency. At the same time, the left part of their body turns out to be significantly more powerful than the right.
An interesting fact: despite the fact that sloths use all four limbs to grasp branches, their left side turns out to be stronger compared to the right. This discovery was made by anatomists from the New York Institute of Technology, including Melody Young, during the world's first attempts to accurately assess the strength of the three-toed sloth.
An unusual feature of sloths
Among mammals, there are very few species that have adapted to life almost exclusively in trees, especially those that feed solely on leaves. In fact, even with an abundance of food, extracting the necessary nutrients from fibrous plant materials poses a significant challenge.
Some mammals, such as giraffes and moose, solve this problem by having large digestive systems. However, not all species can afford to gain mass in a way that facilitates the processing of tough and nutrient-poor plant materials. Others, like koalas, choose accessible food sources and do not waste precious energy resting among the branches.
The elongated bony claws of sloths allow them to hold on securely without expending mass and energy on muscular strength. According to a new study, the grip strength required for sloths to lead their usual lifestyle varies significantly between their right and left limbs.
Scientists developed a special device to measure grip strength in five brown-throated sloths (Bradypus variegatus). The results showed that sloths weighing about 3.8 kilograms have, on average, twice the strength in their flexor finger muscles compared to humans and other primates.
These slow, fluffy creatures can hold more than 100 percent of their weight with one hand or foot, with no noticeable difference between their front and back limbs. In contrast, primates have stronger hind limbs, as they bear 50 to 70 percent of their body weight even while climbing. Sloths, however, distribute their weight more evenly.
Nevertheless, grip strength between the left and right limbs varies by up to 16 percent, especially in the arms. In contrast, in primates like us, there is a predominance of strength on the right side. Scientists cannot explain where such a significant difference in grip strength comes from and what causes it. They also suggest that they may have underestimated the grip strength of sloths, given the limitations of their experimental setup.
