State dependence of arousal from torpor in brown long-eared bats (Plecotus auritus) (2022) Soras et al., Journal of Comparative Physiology B, https://doi.org/10.1007/s00360-022-01451-8
When an animal is facing a lack of prey, or the weather is making it too difficult for them to keep on keeping on, they might choose to enter a state known as torpor. This occurs when the animal lowers its metabolic rate drastically, sometimes to less that 1% of its normal rate. It’s not a perfect solution though, as the costs of torpor include sleep deprivation and memory loss. Nevertheless, it’s a go-to for many small mammals, since they’re warmed up much more quickly than larger ones, and can snap out of torpor when they need to.
It might sound like this is cold-weather behaviour, but it can also occur in summer. Especially if you’re a nocturnal mammal living in part of the world where nights can be very short, or even non-existent, like Scandinavia. Long days means reduced hunting times, so using torpor might be necessary to get through summers as well as winters! This week’s researchers wanted to better understand how small bats survive in northern Norway by looking at how and when they awake from torpor.Read more