Skip to main content

Why do cats kill small animals? A chemical analysis of their whiskers has the answer

Your cat is a cuddly little furball. He’s also a natural-born predator. Domestic cats are considered a globally invasive species, and one 2013 report found cats kill 1.4 to 3.7 million birds each year. Unfortunately, the news about your little sofa lion’s capabilities only gets grimmer from there. Cats may kill more than 20 billion mammals each year, like rats, squirrels, and rabbits. It may come as a surprise, especially if your sweet kitty happily purrs all day and snuggles you to sleep each night.

A new study of cat whiskers is providing more insight into why cats kill animals. Here’s what researchers found and what it teaches us about our feline friends.

a gray tabby cat hunting in grass
Christian Cacciamani / Unsplash

About the study

Dr. Martina Cecchiti and some fellow researchers knew that cats posed a danger to small animals that are vital for a functioning ecosystem, but they wanted to learn more about why cats kill animals. For example, are they hungry, lacking nutrition, or just hunting for fun?

The researchers asked parents of typically free-ranging cats who displayed hunting behaviors in Southwest England to participate. They clipped some of the cats’ whiskers.

The research team told each pet parent to remove anything that might tip off prey or make it harder for the cat to successfully catch an animal, like bells and collars that could alert a bird to the cat’s presence. The human participants took note of any game their kitty brought home for seven weeks.

The researchers sought to understand what interventions reduced predation, so they separated cats into trial groups and gave them a set of preventative measures to try. Some examples of these interventions included puzzle feeders, noise-making collars, high-protein foods, and active playtime. The kitties’ parents continued to collect any prey and freeze it. The goal was to help researchers determine the best ways to minimize cats’ hunting behaviors or, at the very least, the ability to kill small animals successfully.

The cats who had their whiskers clipped at the beginning of the study had them clipped again so researchers could analyze them. Why? The researchers wanted to evaluate the distribution of provided cat food and consumed wild prey. The scientists explained that when a cat eats, markers of that food show up in keratinous tissues like fur, claws, and whiskers. The whiskers could be collected and inspected with relatively little fuss.

Researchers freeze-dried the prey and food samples the study participants gave them, then ground them into powder. They analyzed the powder and whiskers to determine how much of a cat’s diet came from each food source.

Why cats kill small animals, according to scientists

Once researchers analyzed the data, they came to the conclusion that your cat hunts because she wants to and can, not because the food you give her lacks nutrients. Even if a cat successfully captured and consumed prey in the study, it was a tiny portion of their overall diet.

“The diet of domestic cats consists almost entirely of food provided by humans, with only 3-4% coming from captured prey,” the researchers wrote in the study. “This indicates that predatory behavior is likely a result of instinct or stimulation and not driven by dietary deficiency.” The takeaway? Cats in the wild hunt to eat, and Fluffy hunts due to those evolutionary instincts and just because it’s fun for her.

a longhaired black cat playing with a rope
Image used with permission by copyright holder

What the research teaches us

First, there’s nothing wrong with your cat food, and you shouldn’t feel guilty when your cat “window shops” for birds from inside. You’re not depriving him of essential nutrients. Cats are natural hunters, and even thousands of years of domestication can’t eliminate their desire to catch prey.

Allowing a cat to hunt can damage the ecosystem, but you also likely want to keep your feline friend happy. The researchers found that the Birdsbesafe collar cover was the best method for reducing the consumption of wild prey. These collars come in bright collars that are easy for birds to spot, so your cat gets the thrill of the chase while the birds can fly away unscathed.

Other methods to reduce a cat’s hunting instinct included providing food with high meat content and offering objects for playtime. Engaging your cat in a rousing session with his favorite fish pole is a great way to bond and let him act like the tiny predator he is without actually killing anything.

Cats will be cats

Cats love hunting, but your pet cat doesn’t need to kill small animals to get nutrients. Scientists have found that even kitties who successfully catch prey still rely mainly on the food provided by their humans to survive. When cats hunt, it’s simply instinctual. Therefore, you can ditch the cat-parent guilt you feel about keeping your pet inside, and you don’t need to find new food. In fact, it’s better for the ecosystem if you find other ways to help your cat satisfy his needs. Engage your cat with toys, such as fishing poles and food puzzles, so that he can fulfill his drive to hunt without actually hurting another animal. If you’re concerned about your cat’s health or happiness, or if you need more advice about how to curb your kitty’s hunting habit, you can always talk to your vet.

BethAnn Mayer
Beth Ann's work has appeared on healthline.com and parents.com. In her spare time, you can find her running (either marathons…
8 reasons why your cat won’t stop rolling around
If you spy your kitty rolling around, this is what could be behind it
A long-haired cat rolls around on a brown carpet

Cats are famous for their chaotic personalities and unpredictable behaviors, but one of the most random things they can do is roll around on the floor. Most of the time, it seems to come out of nowhere. It's one thing to watch a sleepy feline lie down for a catnap in the sun, but it's another thing entirely when they flop over with all of their might.
While there's no doubt that it's entertaining to watch, not all cat owners or admirers know what's behind this silly-looking behavior. Why do cats roll around? Even though it may look like they're scratching themselves on the ground or asking for belly rubs like a dog, there are several real explanations ranging from obvious to subtle. At least now you'll know.

Why do cats roll around?

Read more
Why cats arch their backs (it’s not always aggression)
There are several reasons for this normal cat behavior
Tabby cat arching their back

Cat owners and non-owners alike have seen the famous Halloween symbol of a black cat with their back arched and hairs raised. The accompanying yowl can be heard in just about every Halloween movie ever made, but it's entirely different when a cat arches their back in real life. In books and movies, though, cats only seem to arch their backs out of aggression or fear. It's almost never a good thing!

However, a cat's arched back can mean many different things. True, it can be a fear reaction or an attempt at threatening another cat, but it can also be a reaction to completely normal, nonchalant things. These are the most common reasons why a cat might arch their back.
A cat's arched back can be a sign of aggression or defensiveness

Read more
Can cats see in the dark? We separate fact from fiction
Cats have night vision far superior than our own, but they still need light to see
A cat stares into the camera

When something goes bump in the night, you might wake up in a panic, only to realize it's just the cat. These beasties are well known for being up and about in the wee hours of the morning, ready to play, hunt, and eat. While it's true that cats love nighttime, they aren't actually nocturnal. Instead, they exist in an in-between state as crepuscular, meaning your feline will love dusk and dawn most. So, if they aren't actually night owls, can cats see in the dark? We break down what cat vision really looks like.
Can cats see in the dark?

Almost all of us can see something in the dark, but night vision varies considerably among different animals. Owls have particularly good night vision, while humans less so. Cats see about six times better than people at night, which helps them hunt successfully at twilight, in the wild, or from your backyard. But it's inaccurate to say they can see in pure darkness. Instead, kitties have special eyes that allow them to observe a lot more in low light. These are the three main ways cats see better at night.
Smart design
Cat eyes look totally different from human ones, and they are. Feline orbs have special qualities designed to help them hunt in near darkness, such as a curved cornea and large lens (we'll get into what's up with the pupils next). You may have heard of rods and cones, the parts of the eye that help us see light and color, among other things. Our furry friends have more rods and so see more light, and therefore, need less of it (by contrast, we have more cones and observe more colors). Lastly, cats have something called a tapetum that reflects light to the retina. While you may never have heard this term, you've definitely witnessed it in action — this is why cat eyes glow in the dark.
Pupil dilation
When the lights go off, our pupils get bigger, and it's the same with cats. However, our pet's pupils can go from a small vertical slit to a massive globe. As the eye grows larger, it does lose some clarity, otherwise you might expect to find your animal's eyes constantly at full blast. Generally, during the day, their pupils will show up as a thin line for maximum focus and then dilate as needed in dim-light situations. And the growth is an enormous difference, up to 300 times the size of their eye at its smallest.
Myopia
Myopia is the fancy word for near-sightedness or the ability to see up close but not far away. Many humans wear glasses to improve their vision, but unfortunately, cats don't ever see as well as we do at a distance. The little buds have a wider frame of vision, but everything would look a bit blurry if you adopted their eyes temporarily. In a competition for who can spot a tiny movement, like prey burrowing in the grass, the cat would win.
How cats see the world around us

Read more