Birds can certainly die with their eyes open. When a bird dies, their eyes do not automatically close like humans’. Their eye muscles relax and their eyes simply remain in whatever position they were in at the moment of death. This means it is not uncommon to find deceased birds with their eyes wide open.
Why do birds’ eyes stay open when they die?
There are a few reasons why birds’ eyes remain open after death:
- Birds lack eyelids – Unlike humans, most bird species do not have upper and lower eyelids that can open and close. They simply have a nictitating membrane that sweeps horizontally across the eye to clean and lubricate it. This membrane does not close over the eye when the bird dies.
- Eye muscles relax – The muscles that control eye movement and positioning relax at death like all muscles. With no nervous system signals, they cannot actively close the eyes.
- Eyes dry out – As part of the decay process, the moisture dissipates from the eyes after death. This causes them to deflate slightly and dry out, essentially “freezing” them in place.
- No need to close – Birds have no biological or evolutionary need to close their eyes after death. Since they are prey animals, keeping the eyes open may help other birds recognize death and avoid wasting energy on attempted predation.
What happens to a bird’s eyes after death?
In the hours and days following death, a bird’s eyes will go through several changes:
- Cornea dries out – The clear dome of the eye loses moisture and becomes dry and cloudy.
- Eyes deflate – With no blood circulation, the fluids drain from the eyeball and it begins collapsing and sinking into the socket.
- Pupils dilate – The pupils will remain fixed in an enlarged, dilated position.
- Color changes – The color fades from the iris as pigment cells lose structure. The eyes take on a flat, dark brown or gray color.
- Tissue breakdown – Enzymes in the eye begin digesting the tissues from lack of blood supply. The eyes shrivel and collapse further.
These changes progress until the eyes eventually shrivel up and sink into the eye sockets. This is often accelerated by insects and scavengers feeding on the decaying eyes.
Do all birds die with open eyes?
The vast majority of birds die with their eyes open. However, there are a select few families of birds able to close their eyes after death:
- Pigeons and doves – In the Columbidae family, pigeons and doves have an extra eyelid called a palpebral membrane that closes horizontally over the eye after death.
- Some waterfowl – Ducks, geese, and swans have a nictitating membrane that can sweep vertically over the eye, partially closing it after death.
- Birds of prey – Owls, eagles, hawks, and other raptors have a lower eyelid with a prominent bulge called the subciliary ridge. This pushes the lower lid up over the eye when the bird dies.
All other bird families do not have anatomical adaptations enabling eye closure after death. Their eyes will remain wide open.
Do bird eyes rot or decompose?
Bird eyes do undergo decomposition and rotting after death like any tissue. The process includes:
- Autolysis – Cell membranes break down releasing digestive enzymes that liquefy the jelly-like vitreous humor inside the eye.
- Putrefaction – Anaerobic bacteria from the gastrointestinal tract migrate into the eyes after death and digest tissues.
- Insect activity – Fly larvae and carrion beetles feed on the nutrient-rich eyes and accelerate their breakdown.
- Mummification – The eyes eventually dehydrate and mummify if decay is halted by cold, heat, or desiccation.
The high moisture content makes the eyes one of the first parts of the body to decompose. Empty, collapsed eye sockets are often one of the more prominent indicators that a bird corpse is in advanced stages of decay.
What causes birds’ eyes to remain open after death?
There are four physiological factors that lead to birds having their eyes fixed open after dying:
- No eyelid sphincter muscles – Muscles like the orbicularis oculi actively close the eyelids in life. Birds lack these important muscles.
- Relaxed orbital muscles – With no neural signals, the four rectus and two oblique muscles controlling eye movement and orientation relax and release tension on the eyeball.
- Rigor mortis – As muscle cells deplete ATP after death, rigor mortis causes generalized stiffening of body muscles, locking the eyes in place.
- Drying of corneal membranes – The clear protective corneas dry out, stiffen, and prevent the eyes from closing.
Combined, these factors trap the eyes in the open position seen at death even as the rest of the facial muscles relax.
Do birds sleep with their eyes open?
Unlike humans, birds are able to sleep with their eyes open. This is made possible by having the ability to essentially “turn off” their brains one hemisphere at a time. Unihemispheric slow-wave sleep allows birds to rest half their brains while keeping an eye open for potential threats.
Both the left and right hemispheres take turns sleeping. Electrical recordings of brain activity have confirmed birds can keep one eye open and the opposite hemisphere awake. The nerve connections between hemispheres are suppressed to avoid sensory information from waking the sleeping side.
Why do birds sleep with half their brain awake?
This unusual ability provides birds several advantages:
- Allows for visual vigilance against predators
- Can scan for food sources or flockmates
- Maintains spatial awareness if sudden flight is needed
- Enables flock communication through one eye
- May provide restfulness equivalent to full sleep
Ducks and other waterfowl have been observed sleeping this way while floating in groups on the water. Their unihemispheric sleep is likely an anti-predator adaptation.
Do all bird species sleep with half their brain awake?
Nearly all bird species studied demonstrate unihemispheric slow-wave sleep patterns. However, there are some exceptions:
- Chickens and quail do not display this ability, potentially due to domestication.
- Guinea fowl seem limited in unihemispheric sleep compared to other birds.
- Sleeping geese keep both eyes open but only one hemisphere awake at a time.
- Woodcocks may close both eyes but keep half their brain awake when sleeping in thick vegetation.
Overall, the ability to sleep with one eye open appears highly conserved throughout modern birds. It evolved early in their lineages as an adaptation for surviving inexposed environments.
How can you tell if a dead bird died with eyes open or closed?
Determining if a deceased bird passed with open or closed eyes requires careful observation for these clues:
- Eyelids – Closed eyelids indicate the eyes were shut. Open, stiff lids means the eyes were likely open.
- Feather wetness – Tear staining around the eyes suggests they were open and became dried out.
- Corneal opacity – Clear, transparent corneas indicate closed eyes. Opaque, dried corneas point to open eyes.
- Eye shape – Sunken, deflated eyes were likely open at death. Round, full-shaped eyes suggest closed.
- Nictitating membranes – Swept across the eye signals the bird potentially closed its eyes.
Comparing the two eyes can also reveal if one or both were open based on differences in preservation and desiccation.
Can dead birds move their eyes after dying?
No, deceased birds cannot voluntarily move or reposition their eyes due to permanent loss of neurological function at death. Any subsequent eye movements are caused by:
- Drying and deflation – Eyes sinking into sockets can shift position slightly.
- Muscle contraction – If death was recent, residual rigor mortis spasms may turn or roll eyes.
- Insect activity – Maggots and carrion beetles feeding on the eyes will move and disturb their placement.
- Decay gases – Buildup of gases inside can push the eyes forward.
- Scavengers – An animal disturb the carcass and move the head, indirectly shifting eye orientation.
While disturbing, these post-mortem movements do not indicate any continued life processes or ability of the deceased bird to control its eyes.
Do birds’ eyes explode after death?
Bird eyes do not violently explode after death. However, the eyeballs may rupture from internal gases as part of the decomposition process. This can occur if:
- The body bloats from trapped gases
- Insects and larvae infiltrate the eyes
- Tissues break down releasing gas bubbles
- External pressure builds up inside the confined space
The eyes are more likely to simply collapse and flatten as the orbitals deflate. But accumulation of gases from decay can gradually build pressure until the eye membranes split open.
Why do some cultures use coins to close dead people’s eyes?
Placing coins or other small, weighted objects on the eyelids of deceased humans is a funerary custom practiced in some cultures. Reasons this tradition developed include:
- Keeping the eyes closed – The weight helps hold the eyelids down
- Providing payment for passage – Symbolically paying the toll for the soul
- Weighing down the spirit – Preventing the spirit from escaping
- Maintaining dignity – Keeping the eyes from opening and startling mourners
- Offering to deities – Gifts for Gods that may guide the dead
While less common today, coins on the eyes can still appear in traditional burials. It remains a way to show respect and ensure the deceased’s rest is not disturbed.
Do other animals die with their eyes open?
Many animals besides birds expire with their eyes open. Examples include:
- Reptiles – Turtles, snakes, lizards, and crocodilians die with eyes open.
- Amphibians – Frogs, toads, and salamanders.
- Fish – Most fish species die with eyes protruding in a “dead man’s stare”.
- Insects – Virtually all insects, like flies, butterflies, beetles, ants, and bees.
- Arachnids – Spiders, scorpions, ticks, and mites.
- Crustaceans – Crabs, shrimp, lobsters, and crayfish.
However, most mammals and some reptiles like chameleons have eyes that close at death. Primates like humans have strong eyelid sphincter muscles that enable eye closure.
Why do some cultures purposefully keep a window open for a dying person?
Some cultures practice leaving a window open in a room where a person is dying. Reasons for this tradition include:
- Allowing the soul to depart – Open windows give a path for the spirit to leave
- Preventing lingering spirits – Closed windows trap souls and prevent moving on
- Providing fresh air – Better air circulation creates a more peaceful setting
- Symbolizing farewells – An open vista represents saying goodbye
- Changing death superstitions – Altering views that closing things retains the dying
While based in superstitious beliefs, the custom stems from wanting to ease a dying person’s transition and facilitate a peaceful, dignified death.
Do eye caps help keep the eyes of the deceased closed?
Yes, eye caps are an effective tool for keeping the eyelids fully closed on a deceased person. Eye caps are small plastic or leather disks that fit over the eye area. They work by:
- Weighing the eyelids down to prevent opening
- Holding the lids in the right position
- Shielding the eyes from being disturbed or manipulated
- Absorbing leakage from the eyes
- Concealing sunken or distorted features
Properly sized and positioned eye caps are difficult to discern on the deceased. They can greatly improve the appearance for mourners while showing reverence.
Conclusion
In summary, most birds do typically die with their eyes open due to their specialized anatomy and the relaxing of muscles at death. While this can appear disturbing to human sensibilities, it is normal for these species. Understanding why birds show this posthumous behavior can demystify the mechanisms behind their passing and remain respectful of the deceased.