This text is part of a series examining the conditions of animals living in the wild. For more texts examining the ways animals in the wild suffer and die, see our main page on the situation of animals in the wild. For information on how we can help injured animals, see our page on rescuing trapped and injured animals.
Physical injuries are one of the most common threats to animals living in the wild. In some cases, animals incur severe injuries that kill them directly. In other cases, their injuries can affect them in ways that are indirectly fatal, for example, by reducing their ability to find food or to evade predators. Even when animals aren’t killed by their injuries, they can be left with chronic pain, especially when their injuries don’t heal correctly.
Animals living in the wild can be injured in many different ways. Broadly speaking, we can categorize causes of injury into three main categories: conflict with other animals, accidental injuries, and injuries caused by severe weather and natural disasters.
Conflicts with other animals can be with animals of other species (predation for example), or they can be with animals of their own species (conflicts over territory or mates, sexual coercion). Other injuries are caused by accidents or extreme weather conditions. For example, baby birds are sometimes injured after falling from their nests, and forest fires can leave animals with burns. Invertebrates get appendages stuck and lose body parts in molting mishaps.
Many attacks by predators do not succeed. Often, animals manage to escape a pursuer even when initially captured, but terrible injuries may result. Hedgehogs are often left with missing or damaged legs after being attacked by foxes.
The footage below shows a hedgehog who is missing her left hind leg, likely as a result of a fox attack. Notice the difficulty with which she walks. Her injury is very likely to reduce her capacity to find food and to evade predators, in addition to the physical pain it must cause her.
This young seal escaped from a shark who was attacking him, but he was left with severe injuries to his flank.
Amphibians such as frogs are often found with deformities such as missing or only partially grown legs. These deformities are caused by selective predation by Dragonfly nymphs on tadpoles.1 Dragonfly nymphs rarely eat a tadpole entirely; rather, they grab tadpoles and find tender parts to eat, usually the hind leg bud. Depending on the stage of development that a tadpole is in when she is attacked, she may completely regenerate the missing limb, the limb may be completely missing, or it may partially develop. The mature frog must then try to survive with a partial or missing leg, or, sometimes, missing eyes. This attack in her tadpole stage thus makes it harder for her to find food and evade predators in her later life.
Physical trauma can also be the result of conflict between members of the same species. For example, animals chase and fight each other to defend their territory, to establish a new social or mating hierarchy, or to protect their young. Competition for food, water, shelter, and other basic needs may lead to aggressive behavior that causes injury.
The video below shows a lone lioness injured after a fight with a group of adolescent males. The fight may have been over territory, an animal carcass, or an attempt at forced copulation. She has a broken tail, an open wound on her left hind leg and she is limping badly. She is unlikely to survive on her own, and she follows the group that injured her in the hope that they will share food with her.
Grey Seals are territorial during mating season. This young seal was found with serious injuries to her face, neck, and eye. Her wounds were most likely caused by another seal. Male elephant seals use their massive body weight and sharp canines against each other when battling for control of a beach and thus control of a harem of females. Though these fights are rarely fatal, they can result in severe tears and cuts to both parties. For example, see:
Animals living in the wild are subject to injuries in their everyday lives. Many accidents result from falls, collapsed dens or burrows,2 collisions, or getting stuck. Birds crash into trees, elephants get stuck in swamps, deers puncture their eyes on low-hanging branches, and squirrels fall out of trees. Animals can also injure each when they are play-fighting.
Many animals sustain crushing injuries caused by accidental trauma. Crushing most often occurs when an individual becomes caught between the ground and a solid object, often a rock or a larger animal. The type and degree of crushing injury depends on the amount of force, resulting in a range of injuries from minor bruising to severe hemorrhage, fractures, and rupture of internal organs.3 For example, rocks or tree branches can fall on an animal. Some animals accidentally step on smaller animals. Male penguins can accidentally crush a pup while they are displaying, which can cause internal injuries. Walruses are easily startled. The approach of a predator or the noise of a passing boat or plane can cause walruses to panic and stampede towards the water. These stampedes are extremely dangerous for calves who may be injured or crushed to death.4
Vertebrates can suffer from a variety of fractures to bones in the spine, head and neck, limbs, jaw, wings, shell, or horns.
Bone fractures in spine, limbs and wings are common and can be fatal.5 Many of us are familiar with horses who can’t survive a broken limb. This because of the way their very light legs bend and shatter, the thin and easily penetrated skin around the bones, and how easily the blood supply is cut off by damaged arteries. They are also susceptible to pneumonia if they lie down for an extended period of time.6
Walruses have been documented falling from cliffs, often in large numbers. Walruses in one wildlife refuge in Alaska have been seen falling from the same cliff since 1996.7 These falls result in death or severe injury. It isn’t entirely clear what is responsible for these accidents. Walruses often haul out onto land to rest, and sometimes when the beaches are too crowded they will climb up gentle slopes, with cliffs on the other side. Once there, they can be spooked by polar bears, or they can simply lose their footing when returning to the sea.8 The video below shows large numbers of walruses falling to their deaths. There are two to three hundred dead on one short stretch of beach. Notice the close up of a walrus who has survived the fall. Still breathing, but unable to move, she must have suffered greatly before her death.
Birds have legs that are easily broken because they are small and often hollow. They may also be fragile due to malnutrition or excessive egg laying. Common causes of broken legs are falls, fights, accidental collisions with other animals, or being accidentally stepped on by a larger animal. Broken bones in the limbs or wings of flying birds and penguins are serious and often fatal.9 The thinness of flying birds’ bones helps them in flight, but makes their bones more prone to shatter or fragment.10
Injuries to the bones around the eye (orbital fractures) occur when there is a direct blow to the face, by a falling rock, running into a tree or wall, falling, or from a kick by another animal. This can cause the eye to hemorrhage, and lead to infection later on.11
Tortoises and turtles can suffer from shell fractures from falls, objects impacts, or being trampled on by other animals. Large fractures can be quite serious. A turtle’s shell serves as a sort of backbone, and a turtle can be paralyzed or their lungs can collapse depending on where the crack is. If the fracture is deep, there can be blood loss. Shell rot can set in due to a fungal or bacterial infection under the crack. Aquatic animals are particularly susceptible to shell rot. There are nerve ending in and around the shell, so it can be painful in the way any broken bone can cause pain.
Horns are also made of bone and can bleed. If torn away near their base, skin will be torn as well.12
Beaks can break from collisions or fights. A bird can also break her beak if she gets it stuck in something. If she panics and rips herself free, she can break her beak off. Beaks are made of skin covered in keratin (the same material as our fingernails). The beaks are attached to bones, and the beak tip has a concentration of nerves and blood vessels. Birds use their beaks not only as mouths but also in the way we use our hands to pick things up. If a bird’s beak is injured, she may be unable to eat, drink, build a nest, or protect herself. Certain breaks cause bleeding, and in some cases, a bird can bleed to death from a broken beak. Injured beaks can also lead to breathing or sinus problems.13 Beaks don’t repair themselves, but the injured part can grow out. The tip continually grows because it is constantly wearing out due to use, but injuries far from the tip can be permanently disfiguring. An injured bird might only be able to eat soft food, which could make it hard to survive in the wild.14
Bat and insect wings can tear from collisions with objects, plants, thorns, or from fungal infections. Tears in bat wings are serious injuries and can lead to blood loss.15 Tears can heal on their own, but torn wings affect flight capability, sometimes preventing flying altogether. The animals also require rest and extra energy to heal, and while they are healing, they are more vulnerable to starvation, predation, and other threats.
Animals in nature can sustain eye injuries due to foreign objects, punctures, or smoke. A common way an animal can receive an eye injury is from running into branches. Because many animals, such as deers and antelopes, escape from predators and other threats by running into the woods, many run into low-hanging branches. While this usually only affects one eye, any permanent damage or vision loss can make the animal more prone to other accidents and predation in the future.
Flying animals are at an advantage because there are fewer things to run into. However, birds can injure their eyes falling out of trees at an early age, or run into branches when taking off. They can also get injured by talons in fights with other birds. Eye injuries that don’t heal inhibit a bird’s ability to fly.
Eyelid injuries, such as rips or punctures, often happen due to falls or running into something. The eyelid is a fragile part of an animal’s body. It can easily be damaged, and if not healed properly, it can lead to vision loss or infection. Getting sand, glass, or other foreign objects stuck in the eye can be very painful for many animals, who might injure themselves trying to get them out.16
Appendages like limbs, wings, and antennae can be lost directly in accidents or fights, but many animals lose appendages by autotomy, or self-amputation. Octopuses amputate their own arms, lizards their tails, and spiders their legs when in danger, usually from getting their appendages trapped or stuck in fights with other animals, to prevent venom from a sting from spreading throughout their body, or in molting mishaps. When it is not to escape from a dangerous situation, self-amputation may be a response to pain resulting from an injury or an attempt to remove a useless body part.17
The degree to which a lost appendage affects an animal depends on the type of appendage, the function of the appendage, and the environment. Some animals, like octopuses and spiders, often manage well when missing an arm or a leg.18
Many invertebrates, especially juvenile ones, can regenerate limbs, antennae, and other body parts through molting. The severity and duration of a repairable injury depends on how old they are, the frequency and length of time molting takes, and the part of the body that’s injured.19 A crayfish who only molts once a year can manage without a leg, but losing a claw or an antenna could seriously impair their ability to survive fights with other animals or explore their environment and seek shelter.20 An unhealed limb can be particularly harmful to jumping insects like crickets.21
It’s not always possible to fully regenerate injured or amputated body parts. The replacement part is not always the same in terms of structure and function. Some injuries don’t heal due to their severity or the age of the animal.22
Some vertebrates have some regenerative capacity, such as lizards who regenerate tails, fishes who regrow fins,23 and salamanders who can regrow limbs.24 Bats can regenerate wings and ears and ungulates their antlers.25 However, the regrown parts may be smaller or weaker, and if the animal is under too much stress, they might not be able to regenerate the part at all.
Molting is a common cause of injury in arthropods. Even when they aren’t injured, arthropods need to molt – shed their exoskeletons – in order to grow, and then their new exoskeletons must be hardened or reconstructed, together with other body parts such as the linings of organs.
Although arthropods are vulnerable to external injuries during molting and while their new exoskeletons are still soft, they are more likely to die or be injured because of a fault in the complex molting process.26 They might also fail to regenerate an injured body part, or, if the injury happens after a certain critical period, be unable to regenerate it during the next molt,27 leaving them with reduced functioning until the following molt, which might be months, or in some cases, years. This is worse for older animals, who tend to molt less frequently as they age.
Some larvae cannot breathe while their exoskeletons are coming off and can asphyxiate if it takes too long or something else goes wrong. Mayfly larvae must take in extra oxygen before they molt because they leave their tracheal lining behind and stop breathing during the molting process.28 In other species, just getting out of their exoskeletons can take months, and if they get stuck, they can be crushed to death as they keep growing.29
Molting arthropods can also tear off a sensitive part as they extract themselves, losing or twisting their limbs, crushing their lungs, or injuring an eye or other soft tissue. Injuries are more likely to occur if an animal experiences abnormal shedding of the exoskeleton, a condition called dysecdysis, which can be caused by stress. Some injuries cause life-threatening hemorrhages.30 Animals are more susceptible to attacks from predators or conspecifics while they are molting. For example, prawns are more likely to be injured or killed by other prawns during certain stages of molting.31
Animals living in the wild have to face extreme weather conditions. These conditions often cause injuries that can be very painful, debilitating, or deadly.
Storms are hazardous for animals who are unable to seek shelter. Sea animals can be thrown against rocks during storms. Water birds are pelted by large balls of ice during hailstorms. This can cause internal organ damage, broken wings and limbs, and eye injuries. Water birds are especially at risk.32
Overexposure can cause sunburn, the severity of which can range from minor scorching to complete destruction of the skin and underlying tissues. The most severe wounds can be fatal. Animals such as hippos, elephants, and pigs have sensitive skin. In order to prevent sunburn, they coat their skin in mud. When mud isn’t readily available, during droughts for example, this isn’t an option and they can suffer from severe sunburn. A drought in Lamu in northern Kenya in 2017 led to hippos and other animals getting stuck in dried out mud ponds. Unable to coat their skin in a protective layer of wet mud, many of them suffered from severe sunburn.33
Cold weather can also cause injuries to animals living in the wild. In severe cold, animals can suffer from frostbite. This stray cat lost parts of his ears and nose after being stuck outside in severe cold weather. Birds can lose their legs when they become stuck to frozen railings.
When an animal becomes injured but does not die, she may suffer in many ways. Firstly, there is the pain caused by her wounds. An injured animal may experience intense pain and discomfort. Pain can also lead to behaviors that are dangerous to the animal, such as causing them to decrease their intake of food and water, leading to weight loss, muscle breakdown, and impaired breathing.34 Secondly, an injured animal is likely to suffer from a range of other problems due to infections and related diseases. In the absence of medical treatment, infection is a natural correlate of wounding in the wild. Damaged tissues tend to become infested by parasites (known as myiasis).35 Parasitic infestation may be extremely painful and may cause additional complications such as diarrhea, vomiting, and visual disturbance.
Finally, the disabling effects of the injury – exacerbated by infection or parasite infestation – jeopardize the animal’s wellbeing in many important respects. Most notably, the animal may not be able to escape from threatening situations or to keep up with their social group. They may also be unable to eat or drink adequately to promote healing or even to stay alive. Injured animals also become preferential targets for both predators and competitive members of their own species. The correlation between poor physical condition and predation has been thoroughly discussed in the scientific literature.36 Predators do not hunt randomly but rather select individuals who seem weak, including those who show signs of illness. As an example, the rate of predation of deers by mountain lions had grown fourfold due to increased prevalence of infection in the population of deers.37
Animals living in the wild are vulnerable to a vast array of horrific physical injuries. The causes of these injuries are many and varied, ranging from the gashes and bites of predators or competitive animals of their own species; fire, frost, and torrential rains; falls and collisions; and self-amputation and molting accidents.
For information about the ways we can help animals in the wild suffering from injuries, see Rescuing trapped and injured animals.
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23 Darnet, S.; Dragalzew, A. C.; Amaral, D. B.; Sousa, J. F.; Thompson, A. W.; Cass, A. N.; Lorena, J.; Pires, E. S.; Costa, C. M.; Sousa, M. P.; Fröbisch, N. B.; Oliveira, G.; Schneider, P. N.; Davis, M. C.; Braasch, I. & Schneider, I. (2019) “Deep evolutionary origin of limb and fin regeneration”, Proceedings of the National Academy of Sciences of the United States of America, 116, pp. 15106-15115 [accessed on 30 June 2019].
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25 Goss, R. J. (1987) “Why mammals don’t regenerate—or do they?”, Physiology, 2, pp. 112-115.
26 Maginnis,Tara Lynne (2006) “The costs of autotomy and regeneration in animals: A review and framework for future research”, Behavioral Ecology, 17, pp. 857-872 [accessed on 31 August 2019]. Mykles, D. L. (2001) “Interactions between limb regeneration and molting in decapod crustaceans”, Integrative and Comparative Biology, 41, pp. 399-406 [accessed on 4 July 2019]. Tower, W. L. “Observations on the changes in the hypodermis and cuticula of coleoptera during ecdysis”, Biological Bulletin, 10, pp. 176-192.
27 Mykles, D. L. (2001) “Interactions between limb regeneration and molting in decapod crustaceans”, Integrative and Comparative Biology, 41, pp. 399-406 [accessed on 13 March 2019].
28 Camp, A. A.; Funk, D. H. & Buchwalter, D. B. (2014) “A stressful shortness of breath: Molting disrupts breathing in the mayfly Cloeon dipterum”, Freshwater Science, 33, pp. 695-699 [accessed on 12 October 2019].
30 Pellett, S. & O’Brien, M. (2019) “Exoskeleton repair in invertebrates”, Veterinary Clinics of North America: Exotic Animal Practice, 22, pp. 315-330.
31 Ibid. Peebles, B. (1978) “Molting and mortality in Macrobrachium rosenbergii”, Proceedings of the Annual Meeting – World Mariculture Society, 9, pp. 39-46 [accessed on 3 September 2019].
32 Montana Department of Fish, Wildlife & Parks (2019) “Hailstorm pummels Big Lake WMA waterfowl”, fwp.mt.gov, Fri Aug 16 [accessed on 4 December 2019]. Jones, J. (2015) “Hundreds of flamingos battered to death during giant hailstone storm”, The Local, 3 September [accessed on 14 February 2019]. SAPeople (2019) “Falcon tragedy: Hundreds of birds die as massive hail storm hits Newcastle overnight”, SA People News, Mar 22 [accessed on 24 August 2019].
33 Karasin, E. (2016) “Hippos dying from SUNBURN amid Kenyan drought: Extreme heat has dried up mud baths the animals use to protect their skin”, MailOnline, 16 March [accessed on 13 December 2019].
35 Pellett, S. & O’Brien, M. (2019) “Exoskeleton repair in invertebrates”, op. cit. Francesconi, F. & Lupi, O. (2012) “Myiasis”, Clinical Microbiology Reviews, 25, pp. 79-105 [accessed on 14 August 2019].
36 Pellett, S. & O’Brien, M. (2019) “Exoskeleton repair in invertebrates”, op. cit. Curio, E. (1976) The ethology of predation, Berlin: Springer. Martín, J.; de Neve, L.; Polo, V. & Fargallo, J. A. (2006) “Health-dependent vulnerability to predation affects escape responses of unguarded chinstrap penguin chicks”, Behavioral Ecology and Sociobiology, 60, pp. 778-784. Penteriani, V.; Delgado, M. M.; Bartolommei, P.; Maggio C.; Alonso-Álvarez, C. & Holloway, J. (2008) “Owls and rabbits: Predation against substandard individuals of an easy prey”, Journal of Avian Biology, 39, pp. 215-221.