Why Do Dogs Sleep With Their Eyes Open?

It is not an uncommon sight to see a dog sleeping with one of its eyes or both partially open; this condition is usually harmless. Any dog caught sleeping with eyes partially open might just be keeping watch on its environment while asleep. Though it is normal to see dogs sleep with their eyes open, regular examination of your dog’s eyes is recommended; this way, you will be able to spot eye defects at an early stage. A vet should be called in whenever you suspect any health issues with your dog’s eyes to rule out serious eye conditions.

Do Dogs Sleep With Their Eyes Open?

Many startled pet parents have always asked the obvious question “Do dogs sleep with their eyes open” but what usually shocks these dog owners is that their dozing pooch still appears to be keeping an eye on its environment and the happenings around it when it is sleeping.

Yes, it may appear a bit unnatural to observe your canine friend keep its eyes partially open during a nap, however, we must acknowledge the fact that one out of five human beings is believed to do exactly the same. In fact, the special ability to keep eyes partially open while sleeping happens to be a common trait found in several species, dogs inclusive.

In the case of the canine population, they have a third eyelid known as nictitating membrane; this sits behind a pup’s outer eyelid. The job of the nictitating membrane is to aid in the cleaning and protection of the eyeball’s surface by sweeping the dust and debris away when the eye is closed. Once a pup opens its eyes, the membrane will instantly retract and take a position at the inner corner of the eyes.

There are animals with the ability to control their nictitating membrane separately without their external eyelids coming to play. However, the canines don’t have this ability – when a dog shuts its eyes, its nictitating membrane automatically closes and it also reopens automatically. When a dog partially opens its eyes during sleep, it is only the outer eyelid that is open, the nictitating membrane remains closed.

Its somewhat translucent nature makes it appear like you are looking directly at the eyeball which is not the case. When closed, the membrane does a good job of keeping the eyeballs protected and at the same time, allows the sleeping dog to pick up stimulus in its environment. This is why the canines can suddenly jolt awake in the case of any emergency.

Why Do It?

The sleep cycle of the canine population is pegged at just 20 minutes, thus, they wake up more often than humans during their sleeping hours; the sleeping cycle for a human being can extend to 90 minutes. Sleeping with eyes partially open has been attributed to the survival mechanism developed by pups during their stay in the wild which are carried over to the domestic breeds. These are some of the reasons dogs sleep with their eyes open;

  • It allows a pup to remain alert to possible dangers like predators. They do this with one portion of their brain.
  • With a dog’s eyes partially open, predators may be tricked to think that the pup is still alert, and the marauding intruder will have no choice than to leave it alone
  • Their brief sleep cycle of 20 minutes is another good explanation for the partially open eyes during sleeping hours; they drift off briefly, wake up and still go back to sleep within short time intervals. This is how they manage to keep tabs on their environment. Even if you catch a dog that would normally close its eyes to sleep with eyes gaping, it may be that it briefly woke up to drift off again.
  • There is this belief that a pup’s eye is capable of sending signals to its brain while asleep. For this reason, it is highly impossible that you can sneak past a sleeping dog without it noticing.
  • Dreaming is another thing that may make dogs sleep with their eyes open. A dog that is dreaming may likely sleep with open eyes and this may be accompanied by some unconscious actions such as twitching of the legs. Dreaming occurs when a pup is deeply asleep and this deep sleep state makes a dog vulnerable

Read Also: Caring For Senior Dogs: 10 Things You Need To Know

Which Dog Breeds Usually Sleep With Eyes Open?

Flat-faced dogs sleep with eyes open source

Anecdotally, people tend to believe that they witness the condition of dogs sleeping with their eyes open more often in some breeds of dogs than others. These breeds of canines are the ones they said are not capable of shutting their eyes fully while sleeping;

  • Dogs with either very flat or very long faces

According to expert reports, some brachycephalic dogs bred specifically to have over-exaggerated flat faces are fast losing the natural ability to close their eyes fully. The reason behind this is that the shape of the dog’s skull forces its eyes to protrude very far from its socket. This occurs in such a way that the lids can never comfortably close over them.

  • Dogs that are bred to have short faces

The dogs that have been specifically bred for short faces like the English bulldogs, the pugs, and the Shih Tzus often suffer from a condition known as lagophthalmos. This does not allow them to blink in the normal way and won’t allow the eyelids to close during sleep. They actually lack the ability to control their facial muscles during sleeping hours, thus, the eyes cannot stay closed.

This defect has been laid at the doorstep of human breeding practices. These pups are also sufferers of brachycephalic, their shallow eye socked also breeds a lot of eye infections for them which has raised so much concern among the experts.

  • Dogs that were originally bred to be hunting dogs

Originally bred to be hunting dogs, breeds of canines like beagles and Great Danes are known to have their eyes partially open in sleep. This is taken as their natural reaction to being constantly “on guard” and always ready to hunt. The half-open eye also helps the breeds to be suspicious of any intruder within a twinkle of an eye. Thus, even if you find these breeds sleeping, they still remain alert.

  • Dogs with bulgy eyes

There are breeds of canines that naturally have prominent or bulgy eyes like the pugs or French bulldogs; for these breeds, their eyes appear to be open while they are asleep.

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