Some animals have very curious habits when they sleep. Horses do it while standing up, albatrosses while they’re flying, and sea otters while they’re drifting along the water (and holding hands because they’re so adorable). Giraffes never even sleep for more than 20 minutes at a time, otherwise they risk being attacked by predators. As people that love a good eight or nine hours in bed, we can’t even cope with the thought of just 20 minutes sleep a night.
Another animal that has intriguing sleep habits is the hummingbird. If you’ve ever wondered what they are, you’re in the right place.
It’s called torpor
When hummingbirds sleep, they go into a state known as torpor. This is where they lower their body temperature and reduce the amount of energy they’re using by a massive 85%. Essentially, they’re like a computer going into sleep mode, only they take a bit longer to boot up again after they’ve had their rest.
Daily torpor, which is what hummingbirds go through, is a scaled-down version of hibernation. It is believed that when animals hibernate, they experience prolonged bouts of torpor to fulfill the same purpose as those who do it on a regular basis.
What is torpor?
Just like with humans, birds are endotherms, meaning they produce heat as a way to keep warm. They do this through thermoregulation which is vital for combatting the surrounding temperature of the air. However, this process is put on pause when hummingbirds go to sleep as a result of torpor. You’ve got to give up something if you’re reducing your energy expenditure by 85%, right? The effect is that these birds end up a bit like lizards in that their body temperature is very low, but they’re able to cope the way a cold-blooded animal would.
The reason that hummingbirds go into this state of mini-hibernation is that there’s nothing to do when night falls. They can’t see well in the dark and therefore can’t feed on nectar or pollen. Staying awake during the night is a complete waste of energy.
Hummingbirds aren’t the only animals to undergo torpor on a daily basis. Bats are known to do it, as are certain marsupials and rodents, such as mice.
The effects of torpor
Sleep for hummingbirds means a heavy drop in energy levels and body temperature, and that poses its own set of risks. When morning comes, it can take these birds 10-30 minutes to get back to their previous state and be responsive to external stimuli. Naturally, this leaves them in a vulnerable position, especially as they only leave themselves with enough energy to make it through the night. It’s a huge risk, but one worth taking for some of that beautiful, beautiful sleep.
So there you have it – the sleep habits of hummingbirds. It’s easy to forget that other animals do things like this differently to us. We’re so familiar with the concept of sleep being lying down, dreaming for a few hours and waking up probably still feeling tired, that it’s hard to imagine anything else.