HOW HIBERN AT ION WORKS
Winter can bring additional survival challenges to the wild, so some animals have evolved strategies that enable them to avoid these colder, leaner months altogether
WORDS AILSA HARVEY
H ibernation is a period of inactivity that many animals undergo when temperatures plummet and food becomes scarce. During the hibernation period, which can vary from days to months depending on the species, animals may alter their biology to change their metabolic rate and reduce their heart rate, breathing rate and body temperature.
These actions are survival responses that conserve the energy needed to keep the animal alive.
The word hibernation is used to describe many different types of animal inactivity. However, there is a specific phenomenon defined as ‘true hibernation’ – a true hibernator will enter a state of deep unconsciousness during the winter months, causing a significant decrease in body temperature and metabolic rate. Other types of hibernation and inactivity are triggered by changes in environmental conditions, which aren’t always at the same time of year. However, in true hibernation, a state of sleep is triggered by an animal’s biological clock. For example, the Arctic ground squirrel has such a regular cycle that they all begin hibernating between 5 and 12 October and emerge together over two days the following spring, between 20 and 22 April.