This is in stark contrast to most homeothermic mammals which maintain a stable, high core temperature via a process of adaptive thermogenesis , and are consequently able to move fast and effectively regardless of the ambient conditions. Three-toed sloths are indeed the slowest-moving mammals on the planet, but exactly how slow is slow? Just like any chemical reaction, cold muscles are slow muscles so cold reptiles are slow reptiles. Conventional wisdom has it that sloths are simple, lazy creatures that do very little other than sleep all day. The fact that slow sloths have been on this planet for almost 64m years shows that they have a winning strategy. There must be a lesson somewhere in that for all of us. Cold-blooded ectotherms such as frogs and snakes, are commonly subject to enforced slow movement when faced with cold temperatures, due to their inability to regulate their own temperature independently of the environment. Food intake and, critically, energy expenditure are likely limited by digestion rate and room in the stomach. The average temperature of the three-toed sloth is around Both two and three-fingered sloths have a predominantly folivorous leaf-based diet, consuming material with a notably low caloric content. They move slowly at all temperatures and, unsurprisingly, deviate from the typical homeothermic mammalian plan by operating at lower body temperatures than most mammals, while apparently having a reduced ability to thermoregulate. It seems astonishing that such an animal survives in the wild at all. And with this, they do not have the capacity to defend themselves or run away from predators, as a monkey might. Plenty of time to hang around for this little sloth. The truth is that sloths are incredibly slow movers, but for a very simple reason: survival. York Festival of Ideas โ York, York. The exact rate of digestion remains unclear, but current estimations for the passage of food from ingestion to excretion range from hours to a staggering 50 days 1, hours. Edition: Available editions United Kingdom. They are energy-saving mammals taking life at a slow pace to avoid the rush and tumble for food, while subscribing the movement patterns that help them avoid being identified as prey. Suzi Eszterhas, www. But this athletic ability comes at a cost: high body temperatures mean high metabolic rates, and somehow the energy bill must be paid using food. They do move, but very slowly and always at the same, almost measured, pace. Author provided All this points to an extraordinary lifestyle, with sloths living on a metabolic knife edge where minimal energy expenditure is finely balanced with minimal energy intake.{/INSERTKEYS}{/PARAGRAPH} {PARAGRAPH}{INSERTKEYS}Becky Cliffe does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment. A sloth sports its backpack tracker. These sloths are the lowest form of existence. So where do sloths fit into this dichotomy? A woman's worth: exploring the gender divide in Pakistani culture โ Cambridge, Cambridgeshire. In , French naturalist Georges Buffon was the first to describe the creature in his encyclopedia of life sciences, saying: Slowness, habitual pain, and stupidity are the results of this strange and bungled conformation. In , French naturalist Georges Buffon was the first to describe the creature in his encyclopedia of life sciences, saying:. Become an author Sign up as a reader Sign in Get newsletter. All this points to an extraordinary lifestyle, with sloths living on a metabolic knife edge where minimal energy expenditure is finely balanced with minimal energy intake. But in order to understand exactly what it is that makes them such slow movers, and why this works so well, we have to look at the biology of these unusual animals in more detail. One more defect would have made their lives impossible. Sloths are not the only creatures in the animal kingdom to adopt a slow pace. Sloths appear to break this rule to an unprecedented extent. Becky Cliffe , Swansea University. Fellow leaf-eating howler monkeys move at a normal pace but consume three times as many leaves per kilogram of body mass as sloths, digesting their foodstuff comparatively quickly. Therein lies another sloth peculiarity: for the majority of mammals, digestion rate depends on body size , with larger animals generally taking longer to digest their food. Instead, their survival is entirely dependent upon camouflage โ a factor aided by their symbiotic relationship with algae growing on their fur. Developing artificial minds: Joint attention and robotics โ Cambridge, Cambridgeshire. Slowness, habitual pain, and stupidity are the results of this strange and bungled conformation. Slow-moving, strategic sloths. There are plenty of other mammals which specialise on a leaf-based diet, but usually these animals compensate for their low-calorie diet by consuming relatively large quantities of food.