Sleepy mouse has its day in the sun
Basking in the sun following a midday kip sounds like the perfect way to spend a warm summer afternoon. If you were a fat-tailed dunnart, a quick sunbake wouldn’t just be relaxing – it could be life saving.
For you and me, a nap is little more than a short period of rest. Some animals, however, undergo a state called ‘torpor’ when they sleep. Bats, echidnas and some species of snake can lower their metabolism for long periods to achieve a state of hibernation during months when food is scarce.
However others, like the mouse-like dunnart, do this for a few hours in the middle of the day to conserve energy and water. Researchers from the University of New England have recently observed its unusual behaviour of warming up after a midday torpor by basking.
While it’s common to see reptiles sunning themselves to raise their body temperature quickly, mammals are ‘homoeothermic’, meaning they can use their metabolism to warm up when their environment is too cold. As marsupials, the fat-tailed dunnart could simply burn glucose to shake off their sleepy-time chills. Given their core temperature can drop as low as 15o Celsius, they would need a large supply of glucose to accomplish this.
In its desert habitat, conserving food and water could be the difference between life and death. The researchers believe that by having a siesta and using the sun to warm up again, the dunnart reduces the amount of food it needs to survive. “Using the sun to passively warm the body saves up to two-thirds of the arousal energy costs,” they say.
Torpor is a useful way for animals to deal with extreme climates. Learning more about how animals deal with climate change could help us protect threatened species. If humans could find a way to do it themselves, it would certainly make space travel a lot easier.
