Why Do Animals Attack Humans? (7 Reasons Explained)

Why Do Animals Attack Humans
Fact Checked and Reviewed by: Mark Rhodes, Ph.D. - Wildlife Biologist
Dr. Mark Rhodes holds an MS in Fisheries and Wildlife along with a Ph.D. in Wildlife Ecology. He helps maintain our editorial standards of accuracy and quality. You can read more about Dr. Rhodes here.

An estimated 47,000 people seek treatment after being bitten or attacked by wildlife in the United States alone. Numbers are even greater worldwide. While statistics vary based on what type of animal bites are included in the study, large carnivore attacks, one of the most deadly, are estimated to happen with a frequency of approximately 5,089 times every year.

While animal attacks can happen anywhere and to anyone, animals often do not attack without reason. In fact, there are several reasons that animals might suddenly (or not so suddenly) attack. By identifying these reasons, there’s a greater chance of avoiding scenarios where animal attacks become more likely.

So, why do animals attack humans?

Animals usually attack humans because of fear, pain, or disease, because their young are nearby, mistaken identity, and in rare cases, because of hunger. Additionally, human and animal territories overlap more as populations grow, making animal attacks more common. Let’s not forget that humans acting irresponsibly is also a major contributing factor to animal attacks. 

Now, let’s jump into the 7 reasons that animals might attack humans so I can explain them in greater detail. Then, I’ll answer some other questions you might have on this topic, like where and when animal attacks are most likely to happen.

Reason 1: The Animal Is Afraid

Perhaps the biggest reason that animals attack is that they are afraid. Animals have a lot of reasons to fear humans, particularly when you consider our long history of putting them in cages and hunting them, either for food or for sport.

Plus, you don’t actually have to be a threat to an animal to be perceived as one. An animal’s instinct to survive, or their self-preservation, typically makes animals avoid people.

One study that tracked the movements of various animals found that smaller predators like bobcats, pumas, and even skunks and opossums, used their habitat differently when they believed humans were nearby. They would make themselves less visible and even cease hunting. As a result, the deer, mice, and other critters that the aforementioned predators feed on would forage more intensely, though they would do so farther away from the area where they believed humans might be.

So, when they spend so much time avoiding people, it makes sense that animals would be fearful if they came face-to-face with a human. Even mightier predators like the lion have a fear of humans, particularly in the daytime and when humans are traveling in groups.

This fear may occur naturally, or it may be something that is learned over time. It’s not uncommon for lions to hunt domestic cattle and other livestock when given the opportunity, especially when they can’t find wildebeests or zebra. Unfortunately, they sometimes also encounter people protecting their livestock and may be shot.

So, this fear may be something learned from experience, passed down to new cubs, or they may have even encountered other lions that may have come face to face with humans and even been shot and lived to tell the tale.

Reason 2: Their Young Is Nearby

While there are some exceptions, most mammals are extremely protective of their babies. After all, their young ensures the survival of the species, something that drives an animal’s natural instinct to mate and produce offspring.

Science tells us this may be caused by hormones in animals during and after pregnancy. Even some of the more paternal male parents experience a decrease in hormones like testosterone, which could decrease their aggression.

Whether it’s hormones, an instinct for survival, or something else, what we do know is that many animals will become incredibly aggressive if they believe there is a threat to their offspring. Even if you don’t approach the babies directly, just being in the vicinity of an animal nest or burrow could lead the parent figure to attack.

There are countless examples of animals that are incredibly ferocious when it comes to protecting their young. Female bears, for example, have to protect cubs from human and non-human threats. In fact, male grizzly bears are known for killing dens of cubs, possibly to reduce competition in the area, even if there’s a chance that he helped father them!

Some animal mothers also ferociously protect their young by refusing to leave an area. Mother foxes, for example, stay with their newborns in the den and provide warmth, never moving until the babies are several months old. The male fox is responsible for bringing her back food.

When it comes time for elephants to travel, they often do so in a circle. At the center of the circle, you’ll find the youngest members of the species. This keeps them safe from predators like lions (and people). Lions won’t take down an elephant unless it’s alone and vulnerable.

You can see at the start of the video how the grown elephants walk protectively around their babies.

Octopuses are another great example- they won’t leave their eggs until they hatch- and this can take up to four and a half years! They don’t even eat during this time and once the eggs hatch, the mother often dies from starvation. Any animal that is willing to starve to death would likely fight to the death if anything were to threaten its babies.

Reason 3: Human And Animal Territories Overlap

The world’s population has grown significantly. From 1800 to 2000 alone, the population grew from 1 billion to an incredible 8 billion.

As the population has grown, so has the need for more development. As humans expand, it uses more natural resources and more space. In many cases, this space comes from natural lands that are already inhabited by animals.

As can only be expected, these animals don’t really have somewhere else to go. So, it’s not uncommon for animal attacks to happen when their territory is encroached upon.

The mighty hippopotamus is a great example of this. With their massive body weight and incredibly long, sharp teeth, hippos are actually the deadliest animal in Africa, killing about 500 people each year.

Even though they primarily eat plant matter, hippopotamuses are extremely territorial and attack when people get close. Their teeth paired with jaws powerful enough to crush bone gives them one of the deadliest bites.

Reason 4: They Are Hungry

Even though humans aren’t part of the natural food chain, animals do sometimes attack humans when they are hungry. In one incident of increased leopard attacks in India, researchers found that there were lower population levels of the leopard’s natural prey during the time.

Of course, the increased leopard population and the higher demand for food would have also played a role. They would attack livestock instead, thus coming across humans, too.

When wild animals prey on humans, they are most likely to attack those that are vulnerable. They won’t approach large groups, but they may attack an individual if they look vulnerable, such as if the individual is crouched over, or if they are small or elderly.

In rare cases, an animal also might get a taste for human blood and prey on people intentionally, according to one report. Human blood does not taste the same as animal blood, as we are known for having high levels of sodium and some big cats occasionally get in the habit of preying on people because they learn to prefer them over deer or their other typical prey.

While this theory hasn’t been proven, it may also have something to do with how salt interacts with brain molecules- even humans can get addicted to salt because of the dopamine response in the brain.

That being said, it’s also worth noting that animals sometimes attack not because they want to eat us, but because they smell food nearby. For example, a bear or raccoon might encroach upon your campsite because they are foragers that eat all types of food, even when it is human food.

That’s why it’s so important to properly store food and food waste when camping- bears or raccoons might also attack if they feel threatened when you stumble on them at your campsite.

Reason 5: The Animal Thinks We Are Its Natural Prey

In the case of shark attacks, the reason may be as simple as mistaken identity. While sharks are known for their multiple sets of very sharp teeth, what they don’t have is great vision.

Sharks like the great white shark hunt their prey from below. Basically, they rely on the shadow that comes across when they are lit up by the natural sunlight to let them know when prey is near.

The shape of a surfboard is similar enough to a seal or sea lion that it puts surfers at greater risk of shark attacks than the average person. Plus, there are fewer sharks that hunt in shallow areas where swimmers frequent, so surfers are more likely to run into them because they’re out in deeper water.

Reason 6: It’s Diseased Or In Pain

Have you ever been hungry or sick and ended up snapping at a friend or loved one? Animals act out like that in the same way. If they are sick, injured, or in pain for any reason, they are more likely to become irritated and bite.

Of course, being diseased also includes diseases like rabies. Animals with rabies are responsible for 59,000 deaths every year– and that is only in people! It’s unknown how many animals may be affected.

When an animal (or person) is infected with rabies, it attacks the central nervous system and causes symptoms like swelling in the brain. This swelling results in behavior changes like aggression, as well as mood changes, blindness, paralysis, and eventual death without treatment. Animals with rabies are also sensitive to light and may feel anxious, which can also cause them to bite.

Reason 7: People Aren’t Always The Most Responsible Species

You don’t have to look too hard to find wild animals attacking people on safari, especially after they break away from the group to get closer for a picture, or even worse, try to take a selfie with the animal. There is a reason that tour guides instruct people to stay inside the safari vehicle and these people don’t realize their stupidity until an animal gets up close and personal.

While animals don’t usually attack safari vehicles for a number of reasons, one of the biggest reasons is that they see this large, unfamiliar beast as some kind of possibly dangerous animal. When people separate, they no longer have the protection of being part of, or an appendage of, this “animal” that wild animals are scared of.

People may also approach wild animals. Even if they don’t necessarily mean harm, animals don’t know that. Plus, their long history with humans doesn’t give animals much faith that we aren’t trying to hurt them. Even if you think you are approaching them in a kind, gentle way, animals may take it as a threat.

Finally, keep in mind that animals can sense fear. This means that when they hear your heart rate increase, smell increased levels of adrenaline and body sweat, or see you trembling or acting afraid, they are more likely to attack. This is the reason it’s so important to stand tall, act calm, and maintain eye contact when you see an animal in the wild, showing that you are a fierce predator and are not going to back down.

Where Do Wild Animals Attack the Most?

Wild animal attacks are most common in lower-income countries than they are in developed areas like the United States. For example, the study mentioned earlier that tracked international predator attacks identified South Asia as being the most deadly when it comes to animal attacks. India and Bangladesh also led in tiger attacks.

In under-developed countries, people are likely to be attacked when doing things like washing laundry, fishing, tending to livestock, or bathing in the river. By contrast, people in developed nations are more likely to be attacked when they are out in the wild for recreational activities.

Why Do Animals Attack Humans In Low-Income Countries More Frequently?

While we can’t conclusively answer “why” wild animals do anything, it is believed that there are a few possible reasons wild animals attack more frequently in low-income areas.

First, many developed countries aren’t native to bigger cats like lions and tigers, which are more likely to attack a person than something smaller like a bobcat or puma. Bear attacks would be more common.

Additionally, because people are more likely to be attacked while carrying out daily tasks like laundry or bathing, there is more opportunity to be attacked in low-income countries. This is especially true when people are out on their own, as even big predators aren’t likely to attack if you are in a group of people.

The way that land is (or isn’t) developed also plays a role. Animals generally have a good sense of smell and they likely associate the CO2 emissions of developed areas with cars and humans. While we cannot say what animals view cars as for sure, they likely avoid them because they think that these cars are big predators.

Additionally, there is more agricultural land in low-income countries. Big predators may hunt livestock, particularly if their preferred food source is unavailable. People that tend to livestock may be attacked in the process.

What Animal Attacks Are Most Common?

In a study that looked at animal attacks from large predators all around the world, researchers collected data on animal attacks from the years 1950-2015. Sloth bears were responsible for 1,337 attacks followed by tigers at 1,047 attacks.

The other large predators in the research include Asiatic black bears (765), brown bears (664), wolves (414), American black bears (403), lions (282), leopards (205), coyotes (140), cougars (135), jaguars (25), and polar bears (23).

Additionally, while it’s not known how many people are attacked by saltwater crocodiles each year, the number has to be significantly higher than the number killed. And, according to wildlife ecologist James Perran Ross of the University of Florida, crocodiles kill an estimated 1,000 people every year.

Keep in mind that these animal attacks don’t involve bites from spiders, scorpions, snakes, or other venomous species that might kill in that way.

What Animals Attack And Kill Humans the Most?

According to BBC, the deadliest animal to humans is actually the mosquito, which is responsible for around 725,000 and 1,000,000 deaths every year from spreading disease. However, the mosquito isn’t necessarily attacking or intentionally causing harm to humans.

When it comes to venomous animals, the saw-scaled viper is most likely to cause death. These vipers are responsible for 138,000 deaths every year. This is likely because it is an aggressive snake that doesn’t necessarily shy away from heavily populated areas.

Finally, for animals not yet mentioned, it’s worth noting that about 500 deaths per year are attributed to elephants, and another 500 are attributed to hippopotamuses.

Will Wild Animals Attack Humans?

Yes, wild animals will absolutely attack humans if they have a reason for attacking. And, as you can tell from all the reasons an animal might attack, animals have plenty of motivation.

Even though these attacks sometimes cannot be avoided, particularly in lower-income countries, being respectful of wildlife goes a long way. Just consider if that photo or selfie is worth the danger you are putting yourself in approaching a wild animal. Even though you may have good intentions, the animal has no way of knowing that.

Will Domesticated Animals Attack Humans?

Yes, domesticated animals absolutely will attack humans if provoked. An estimated 4.5 million people are bitten by dogs every year in the United States alone and of those people, about 80,000 need medical attention for the bite. Plus, dogs only represent a small portion of domesticated animals- cats, horses, camels, pigs, and other livestock and pets also make the list.

Even animals kept as pets sometimes attack, particularly if they feel threatened or are hurt. Animals cannot always communicate when they are sick, in pain, or want to be left alone. Or at the very least, they can’t communicate with their words and use body language instead. When body language is ignored, of course, an animal is going to bite.

In the case of livestock and animals like domesticated camels, they may attack for a number of reasons like those mentioned earlier in this article. Animals can be dangerous, particularly those with hooves like horses, cattle, camels, and pigs. There was a case of a 49-year old man that was killed by a pig– he was found with her and her piglets.

Why Do Animals Attack When You Run?

First, when you run from an animal, they are likely to give chase. Even the most well-trained, domesticated dogs may chase after someone who is running because of their natural instincts.

Plus, running shows that you are afraid of the animal. It isn’t uncommon for animals to attack when they can tell you are afraid. If you are scared of them, it gives them the confidence to think that they could win in the encounter.

Finally, animals may attack someone who runs because they have their back turned. After all, you aren’t going to run toward an animal. To successfully survive an animal encounter, you have to keep your eyes on them. Once your eyes are elsewhere, they believe they have the upper hand and can sneak up on you, which makes it more likely that they will attack.

Why Do Animals Attack When Scared?

The reason animals attack when scared comes down to their natural instinct for survival and their fight-or-flight response. When an animal faces something it’s afraid of, like in humans, they get anxiety from the adrenaline rushing through their body. Even humans have this basic instinct.

Essentially, this leaves them with two options. They either retreat by running away or they are going to attack. Usually, it depends on whether or not the animal sees you as a threat or something that it is able to take down.

So, while animals will attack if they are afraid, if you come face-to-face with certain predators, your best bet is to know what type of animal you are dealing with. Be familiar with wildlife in an area before visiting it and read up on the best way to react during encounters with the local wildlife.

Do Animals Attack Humans For Food?

While hunger isn’t the most common reason for animals to attack humans, there are instances where animals attack with the intention of making a person its food. This happens both intentionally and unintentionally.

When it happens intentionally, it often happens because an animal is unable to eat its natural food source for some reason. For example, some animal attacks happen because predators are trying to hunt and eat livestock and they encounter humans while trying to eat.

In rare cases, as mentioned above, animals can also get a taste for human blood. Of course, they would have to have enough encounters with humans for this to happen.

When it happens unintentionally, it likely happens because of mistaken identity. If an animal mistakes you for its natural food source, then of course it will try and take a bite.

How Likely Is It That A Person Survives An Animal Attack?

The likelihood that a person survives an animal attack comes down to so many factors like what animal they are attacked by, whether they are able to escape and get help, how well they can fight off the animal, and if the animal is hungry all play a role in whether or a not a person is likely to survive.

According to data collected from 1950 to 2017 that included 5,440 large carnivore attacks, approximately 32% of these types of attacks were fatal and 68% resulted in severe injury.

While animals may be afraid of humans, humans are actually relatively easy prey, especially when they’re out on their own. We are often caught without a weapon and we don’t have sharp teeth or sharp claws. Plus, animals are generally stronger than us.

People are also often poorly prepared mentally for an animal attack. Most people panic if they are attacked by an animal, hindering their ability to think clearly and fight off the animal.

Final Word

So, why do animals attack humans? They may attack because of fear, their young being nearby, its territory being encroached upon, pain or disease, mistaken identity, hunger, or human stupidity.

While animals attack most frequently in low-income countries, animal attacks can happen anywhere. This is especially true when you’re out exploring in their natural habitat.

The best defense is to be aware of your surroundings and respectful of the wildlife around you. There is no picture opportunity that is worth the risk that comes with approaching a wild animal.