Cats are clearly related to certain other animals, like lions and tigers. But how closely are they related to dogs, or foxes? And how closely are cats related to people?
What are cats related to? Housecats are closely related to big cats, which are part of the same family (Felidae). However, big cats have several adaptations that distinguish them from housecats: they have larger and stronger jaws, larger muscles, and are better adapted to processing a high-protein diet. Cats share a last common ancestor with dogs that lived about 55 million years ago, and a last common ancestor with people that lived 90 million years ago. Cats are mammals, so are distantly related to all mammals from people to rats and bats.
The guide below starts with a little science. It defines what species cats are, what genus they are a part of, and what family. We can then explore how closely or distantly cats are related to other animals, including lions and tigers, dogs and foxes, and even rats and snakes.
What Are Cats Related To?
Cats are most closely related to the other animals we refer to as cats: the big cats. But cats don’t exist in isolation from other families.
To understand which animals cats are closely related to, and how closely they’re related to them, we have to understand a little something about the way animals are classified by scientists.
What Family Are Cats In?
Cats are a part of the Felidae family. Felidae is a family of mammals within the larger grouping of carnivores (Carnivora). Animals within this family are defined by the following features:
- They have claws that can retract back into their paws. This helps them catch hold of prey, but also to avoid causing too much damage during play-fighting, or when the claws are caught in something.
- They tend to be slender and muscular with strong limbs.
- They have large teeth (relative to size) and strong facial muscles to bite with.
The domestic cat, of course, has been bred for centuries now. That’s why a sphynx cat looks so different from a persian, for example. But despite how different certain cat breeds look, they remain a part of the same family, and closely related to each other.
What Species Are Cats?
The domestic cat’s species is Felis catus. The species’ ‘first name’, Felis, refers to its genus. A genus is a small grouping of animals that are very closely related to one another, but are not considered the same species. The boundary marker between species is typically whether one kind of animal is able to successfully breed with another, even if they look and act the same.
It works like a pyramid. The bottom layer is made up of species and subspecies. The layer above is the ‘genus’ layer, with each species/subspecies belonging to only one genus. Above the genus is the family, which in this case is Felidae; again, each genus only belongs to one family. Animals in the same genus are the most closely related, while animals in the same family are reasonably closely related. As you move up the pyramid, you move to classifications such as ‘class’: mammals are a class, for example. Animals in the same class are only distantly related (like mice and great apes, which are both mammals, but are clearly very different).
This might all seem a little boring, but it’s essential to understand this so that we can define how closely cats are related to other animals!
Are Cats Related to Lions?
Cats are closely related to lions, but not too closely related.
Lions are a part of the genus Panthera. This is a genus within the family Felidae, which contains tigers, lions, leopards and jaguars. They are classed together as one small genus because these are the only cats with the specific anatomical structure that allows them to roar. This is partly related to a bone called the hyoid bone, which isn’t fully formed in these big cats; it’s also related to the structure of the larynx.
As such, lions are classified as a different genus to house cats. But that doesn’t mean they don’t share features; so, how closely related are cats and lions despite being classed differently? They share almost their entire DNA with each other, bar a few percentage points. Their bodily structures are much the same; the lion brain and cat brain are similar, as are the two species’ musculature, dietary habits, and certain aspects of behavior. They do differ in some ways; lions live in prides, while housecats prefer to live alone, and lions are better suited to a meat-only diet (although housecats are still obligatory carnivores). But in the entire animal kingdom, cats are closest related to lions and other big cats.
Are Tigers Similar to House Cats?
Tigers are classed in the genus Felidae, just like lions are. This means they aren’t classed in the same genus as housecats, only the same family. Often, animals only classed in the same family are distantly related; but that’s not the case with tigers and our cats.
As you might imagine, the question of how closely related these animals are has been much studied. One study that garnered plenty of press attention was published in the journal Nature Communications, titled “The tiger genome and comparative analysis with lion and snow leopard genomes.” A genome, if you didn’t know, is an animal’s complete genetic code from start to finish. Scientists have mapped out the entire DNA structure of tigers, lions and house cats (and people!) so that we can understand more about what makes us mammals what we are.
The scientists started off with the DNA of each species. They took a sample from a 9-year old male Amur tiger from the Everland Zoo in South Korea (part of South Korea’s largest theme park). After analyzing it, they found that it was 95.6% similar to the genome of a regular house cat, which is quite close indeed. For comparison, the human and gorilla genomes have 94.8% similarity. The scientists behind the study estimated that the species which became tigers and housecats diverged about 10.8 million years ago, which isn’t long in an evolutionary sense.
They were also similar in other ways. Something that we don’t fully understand about DNA is that there are lots of repeated sections in it. These used to be called ‘junk DNA’, since scientists couldn’t figure out what they did. It’s now thought that they play a role that we don’t yet know, and so are more important than we gave them credit for. Tiger and housecat DNA repeat themselves in much the same way, with the repeats in the same places, and the same overall amount of repeated DNA (39.3% and 39.2% respectively). Other closely related species, like humans and other great apes, don’t have this same connection.
Are Cats Related to Dogs?
Cats and dogs are famous for how they don’t get on. But that doesn’t mean they’re entirely distant genetically.
Dogs aren’t the same species as cats; they aren’t in the same genus, and they aren’t even in the same family. Cats are in the Felidae family while dogs are in the Canidae family. Both domestic dogs and cats are classed as Carnivora, which is an ‘order’. Orders are large groupings that all the different families of animals belong to. Examples of orders include Carnivora, Rodentia (rodents), primates, Chiroptera (bats), and more. Animals within the order Carnivora specialize in hunting and killing other animals.
So, how closely are cats and dogs related? The last common ancestor of both was alive about 55 million years ago. That was long after the dinosaurs were around. This isn’t an exact date, but it’s the one that’s best supported by current evidence. Scientists working in Belgium found a mammal tooth that belonged to a species they called Dormaalocyon latouri; this species was a 2lb mammal that lived in trees and fed on other mammals and insects. We can tell that it likely ate other animals because of the shape of its teeth. It probably looked like ‘a cross between a tiny panther and a squirrel, with a prominent tail and a cat-like snout’.
It’s likely that there are other common ancestors further back in the mists of time that we haven’t discovered yet. Until then, this is all we know!
Are Cats And Foxes Related?
Foxes are interesting animals. Ask random people and most might tell you they’re related to dogs, but some might tell you they’re related to cats. What’s up with that?
Foxes are part of the Canidae family, along with dogs. That means the earliest ancestor we know of that cats and foxes share is the same as the one that cats and dogs share. As for why foxes are more cat-like than, say, wolves, that’s simply a result of their evolution. They evolved to be slender and catlike so that bigger, stronger predators wouldn’t find them.
Are Cats Related to Humans?
Housecats and people are much more distantly related than any two species considered above.
Let’s start off with the obvious: humans and cats aren’t the same species. We also aren’t in the same genus, or in the same family, like housecats and big cats are. So, how far up the ladder do you have to go before people and cats are classed in the same grouping?
You might have guessed already: we’re both mammals. Mammals are defined as animals that give birth to live young and feed them with milk. That’s a very, very broad grouping that includes animals as small as mice and others as seemingly distant as the blue whale (or the human). Despite that, mammals share many features that support the idea of putting these disparate animals in the same group:
- All mammals have a neocortex. This is a region of the brain that’s used for highly advanced things like sensory perception, cognition, spatial reasoning and language. While the human neocortex is more advanced than that of, say, a squirrel, all mammals have one.
- All mammals have some kind of fur or hair. The point of fur or hair is to keep warm, which helped our evolutionary ancestors survive. Even whales have rudimentary hairs.
- All mammals have three middle ear bones, scientifically termed ‘ossicles’. These are the malleus, incus and stapes.
While we aren’t very closely related, we do still share a common ancestor—as does all life on the planet. It’s thought that the animals that became us and the animals that became cats diverged about 90 million years ago, which is much longer ago than housecats and big cats, and longer even than cats and dogs. What’s fascinating is that we haven’t yet found this common ancestor, but scientists have been able to estimate what it may have looked like based on its mammalian descendents. According to the press release on the Nature website:
A team of scientists in the United States and Canada has now reconstructed the appearance and anatomy of this creature — the forebear of all ‘placental’ mammals, which give birth to live young at an advanced stage of development — in unprecedented detail, using a record-breaking data set of anatomical traits and genetic sequences.
The critter turned out to be a tree-climbing, furry-tailed insect eater that weighed between 6 and 245 grams. It gave birth to blind, hairless young, one at a time. Its brain was highly folded, and it had three pairs of molars on each jaw.
“It’s like bringing a fuzzy photo into focus,” says lead author Maureen O’Leary, a palaeontologist at the State University of New York at Stony Brook. “The fact that it’s a small scrambling animal isn’t a surprise,” she adds, but the reconstruction is more detailed than anything else ever attempted, and provides a picture that future fossils can be checked against.
This isn’t just complete guesswork, either. It involved analyzing the genomes of many different mammals, and figuring out how we are similar, and how we are different. By looking at both the features that are common to us all, and the traces of others that aren’t still expressed, scientists were able to estimate roughly what this ancestor was like.
What About Other Animals?
There aren’t any other animals that cats are very closely related to. There are, however, many more mammals—so lots of animals that are at least in the same class.
- Are Cats Related to Rats? Rats are another kind of mammal. They’re in the order Rodentia, meaning ‘rodents’. They’re classed in that order alongside other well-known rodents like mice and squirrels. Rats and cats are about as closely related as people and cats are. That’s because our last common ancestor with the cat is the same common ancestor as rats have with cats. The order Carnivora broke away from rodents before primates did.
- Are Cats Related to Bats? Cats and bats, believe it or not, are distantly related too. Bats are a kind of mammal just like we are, but that’s about as far as the similarities go.
- Are Cats Related to Snakes? Of all the animals considered here, snakes are the most distantly related to cats. That’s because snakes are a kind of reptile descended from dinosaurs. It was only much later that mammals diversified, which they only could when the dinosaurs went extinct.
More and more studies are being done, so hopefully, we will come to understand even more about the cat’s place in the animal kingdom in the future.