When animals sleep with their eyes open, it’s equal parts disturbing, fascinating and puzzling. Chinchillas are one such animal, and when you notice them sleeping this way for the first time, it can be shocking.
Chinchillas can sleep with their eyes open because they can close their pupils by contracting the muscles in their irises to block out light. This means they don’t have to close their eyelids. This gives the appearance of being awake, which deters predators. This isn’t a sign of any health issue, and is common, so is nothing to worry about.
You can disturb your chinchilla when it sleeps like this by poking it or picking it up. But don’t, because if you do, it’ll learn to dislike you! Wouldn’t you if somebody kept disturbing your sleep? Our guide below explains how and why chinchillas sleep with their eyes open, and how to tell if yours is.
Can Chinchillas Sleep with Their Eyes Open?
Chinchillas frequently sleep with their eyes open. This isn’t a sign of any medical condition, or anything else wrong with your pet. Rather, it’s a natural adaptation that the chinchilla has developed to help it in the wild. This behavior has been passed on to pet chinchillas.
But to accept such a simple answer is to misunderstand what’s going on. That’s because while your chinchilla is sleeping with its eyes open, that doesn’t mean it’s looking around. Your chinchilla can’t see when it’s asleep, and there are two reasons for that.
The first is that sensory signals are blocked off by the brain during sleep. Only something thoroughly disturbing is enough to wake an animal during deep sleep, which is why people can sleep through loud noises, and why you may have to shake somebody hard to wake them. The brain is ignoring the sensory signals that the body is sending it, and that applies here too.
On top of that, chinchillas have the ability to close their pupils fully. It can be difficult to see a chinchilla’s pupil, as its eyes are such a deep, dark shade. But chinchillas have slit pupils which can be completely closed.
There are muscles in the eye, specifically in the iris, the structure that surrounds the pupil. These muscles can expand and contract like any other muscles, completely shutting light out of the pupil. This means your chinchilla can’t see even if its eyes are open as it sleeps.
How Common Is It to See a Chinchilla Sleep with Their Eyes Open?
While it can be disturbing to see a chinchilla sleep without closing its eyes, this isn’t unique to just your pet. All chinchillas can do it—it’s very common.
One of your chinchillas may display this behavior frequently while the other never does. The other may sleep on its side or in a hammock, instead. This doesn’t indicate that one of them is ill while the other is well: this is nothing to do with any health condition.
It’s also normal to notice this for the first time after you have had your chinchilla for a while. The onset of this behavior may have taken a long time, or perhaps you hadn’t noticed before. Again, this is nothing to worry about.
Why Does a Chinchilla Sleep with Eyes Open?
There are several reasons why chinchillas sleep with their eyes open. Most are related to the fitness of the chinchilla to survive in its natural habitat. In other words, sleeping with eyes open gives the chinchilla an advantage in its fight against its environment and its predators.
1) It Doesn’t Disturb Them
It’s difficult to understand how sleeping with your eyes open is possible. Keeping your eyes open is the opposite of sleeping: if you’re nodding off at your desk, you do anything to keep your eyes from shutting, because that’s how you stay awake.
But for the reasons described above, this isn’t a problem for chinchillas. They can close off their pupils to block out light, even the bright light of daytime (as chinchillas can be active during the day). And when in deep sleep, the brain blocks off the signals it receives from the eyes anyway.
2) To Ward Off Predators
By keeping its eyes open, the chinchilla appears to be awake. This effect is even more convincing as chinchillas can sleep standing up. A predator that sees a chinchilla sleeping like this might think “I’m wasting my time—that chinchilla can see me coming!”, and go off to hunt other prey. This may only work a few times out of ten, and sometimes, the predator attacks anyway; but that’s still a significant advantage in terms of evolution.
This would be an especial issue for chinchillas as they take frequent short naps rather than one long sleep. This is due to the chinchilla’s diet, as it doesn’t get the energy necessary to stay awake and active for long periods from hay alone. This means that this behavior is even more useful.
3) To React Quickly
Opening the eyes takes hardly any time at all. But when it wakes up, an animal may have to rub its eyes to get rid of gunk, and may be slow to react to the things around it. By keeping its eyes open, the chinchilla can react quickly to anything it sees immediately upon waking.
Again, this gives the chinchilla an evolutionary advantage. More chinchillas can escape from predators that attack them while they sleep. They then pass on their genes, and this behavior to the next generation.
4) No Reason
While we do know a lot about chinchillas, we don’t know everything. There may be reasons other than those covered here which make a chinchilla sleep with its eyes open.
There may also be no clear reason for your chinchilla’s behavior. Any owner will tell you that sometimes their chinchilla does something completely puzzling that can’t be explained, no matter how much you study or think about it. This could be the case for why your chinchilla sleeps with its eyes open.
Chinchilla Sleeping with Eyes Open and Barking
Something else you might notice is your chinchilla sleeping with its eyes open, and barking. This is less common than just sleeping with eyes open, but it does happen.
This can be quite disturbing, because it leads to some puzzling behaviors. Owners report checking on their chinchillas to see what’s the matter, only for the chinchilla to be shocked when it’s touched or disturbed as if it was woken up. That may, in fact, be what happened as chinchillas can bark in their sleep.
The cause of this behavior is a mystery. It could be that the chinchilla heard something that disturbed it enough to bark, but not to wake up. Or, the chinchilla could be barking in reaction to something that it’s dreaming about. It may be impossible to tell why, but what you can be sure of is that this doesn’t indicate a health problem or anything else you should worry about (although it is a little disturbing).
How to Tell That Your Chinchilla Is Sleeping with Its Eyes Open
You may observe your pet for a while, and think “Why is my chinchilla staring at me? Does it want something—or is it angry?” only to find out that it was actually sleeping. Some owners tell stories of their chinchillas sleeping on their sides with their eyes open, looking as if they’ve passed away, only to leap into the air when disturbed.
Chinchilla Sleeping with Eyes Open vs Relaxing
Alternatively, your chinchilla may not be sleeping at all. It could be awake, but just relaxing.
There’s a consistent way to tell whether your chinchilla is sleeping with its eyes open. That’s to touch your chinchilla or make a sound that’s loud enough to disturb it. If you do, your chinchilla will be shocked, but will definitely also be awake!
If you know that your chinchilla frequently sleeps with its eyes open, don’t disturb it each time you see it doing so. Waking your chinchilla this way causes it significant stress, and it will associate you with that bad feeling. If you’re worried about your pet, look for the signs of its breathing, or wait a few minutes to see if it wakes up. Chinchillas take naps throughout the day, so you shouldn’t be waiting long.
In some cases, touching the chinchilla lightly won’t wake it up. Only picking it up or touching it roughly will wake it. If that’s the case, then there may be something wrong, whether it has its eyes open or not. Your chinchilla may be lethargic, in which case it’s severely sick. Talk to a vet if it doesn’t perk up.