Are Horses Related To Deer? (Answered!)

The other morning, I was walking down to my pasture to check on my horses early as the sun was rising.

Before I got there, I noticed from a distance that there was something else in the pasture.

On closer inspection, I noticed it was two deer.

They were sort of just hanging out with my horses, neither really bothering the other.

We live near a forest so they must have come out and jumped the fence in the night, but it got me wondering if horses and deer were closely related.

So, are horses related to deer?

Horses and deer are not very closely related. As far as subclassifications go, horses and deer only share the distinction of mammal. Deer are even-toed ungulates, meaning they bear their weight on cloven hooves. Horses are odd-toed ungulates, with only one toe per foot.

So, though it might be natural to think they’re closely related, horses and deer are actually not all that closely related.

They are both mammals, and this is about where the similarities end in terms of scientific classification.

With that in mind, let’s look at this question in more detail.

What is the closest relative to a horse?

Horses are part of the Equus family, of which there are only seven extant species.

This includes horses, zebra and donkeys, and other species like onagers.

Most of these species are immediately recognizable as somehow ‘horse like’, since they share many of a horse’s key features.

Donkeys are like smaller horses; zebras are like stripey horses.

Obviously, it is more complex than this, but this is the general idea.

Horses are actually, evolutionarily speaking, quite isolated.

There isn’t a great deal of creatures directly related to them.

As I mentioned, one of the main distinctions is between even-toed or odd-toed ungulates.

Horses balance their weight on only one toe per foot—the hoof counts as one toe.

A deer’s hoof is cloven, making it an even-toed ungulate.

This definition of even or odd-toed ungulate even of itself is a rather large classification including many animals.

The fact that horses and deer do not share even this classification shows you how distantly related they are.

So, what about deer, then?

What are deer closely related to?

What is the closest relative to a deer?

The simple answer is just other deer.

Unlike horses, which are separated by breed but not species, there are dozens upon dozens of deer species across the world with very different adaptations.

They are all contained within the family known as Cervidae.

This includes all ‘old world deer’, referring to where they originally emerged.

Beyond that, they are classified in the order Artiodactyl.

This is the group of even-toed ungulates which bear their weight on an even number of toes, usually two.

This includes a vast number of species, but deer are most closely related to things like elk, moose and caribou.

More distantly, deer are related to other cloven toed animals like pigs and camels.

Horses fall nowhere near this evolutionary timeline.

But, every animal on earth is somehow related, however distantly.

So, horses and deer must have a common ancestor somewhere on the tree of life.

Do deer and horses have a common ancestor?

Technically speaking, all animals alive today have a common ancestor.

However distantly we might be related, we all sprang from the same evolutionary tree.

So, how far do we have to  go back to find a common ancestor between horses and deer?

The answer is not really that simple, as the evolutionary records are in a state of constant incompletion.

Horses in something approaching their modern form first began to emerge about 55 million years ago.

Deer, or similar ungulates, first appear in the fossil record about 50 million years ago.

They are thought to have evolved from similar ancestors with no antlers but with tusks.

So, this gives you an idea how far back you would need to go to find a common ancestor.

These two animals as we know them emerge around 50 million years ago, meaning their common ancestor would have lived long before that.

It’s hard to know for sure, but the simplest answer is more than 50 million years ago.

Can a deer breed with a horse?

There is certainly a simple answer here: no, they can’t! Animals can only interbreed with species that are very closely related to themselves: for horses, it’s pretty much limited to donkeys and zebras.

A species can only interbreed if the possess the same number of chromosomes and have similar enough genetic makeup.

Horses and deer separated from one another perhaps as much as 100 million years ago, and they’ve become distant strangers in that time.

Your dreams for a horse-deer hybrid are unfortunately not possible.

Though they might share a lot of somewhat superficial similarities, horses and deer are actually very different.

They are on completely separate evolutionary branches, and their common ancestor lived tens or hundreds of millions of years ago.

They essentially evolved to live a very similar life, often on very similar terrain, and this kind of convergent evolution is more responsible for perceived similarities than being especially closely related.