How Many Hearts Does A Horse Have?

Horses are big animals.

So big that it can make us wonder about their exact anatomical makeup.

You have to wonder what kind of evolutionary engineering goes into making a bulky creature like that be able to carry all that weight at all, let alone run as fast as horses do.

The other day, while out tending to the horses with my son, he asked me if a horse needed more than one heart in order to be able to pump blood all around that huge body.

I wasn’t sure, but it sounded like he could be right, so I decided to look into it.

How many hearts does a horse have?

Surprisingly, a horse only has one heart. Most mammals do indeed have only one heart, but horses have other means to aid in the pumping of blood around their body, such as the ‘frog’ in their hooves. Hooves have one, large heart.

So, it’s actually very uncommon for mammals to have more than one heart.

Horses are no exception.

It might be impossible to think how only one heart could pump blood around their huge bodies, but the fact is they have other things in place to help them with this.

So, let’s look at it in more detail.

How many hearts should a horse have?

A horse should only have one heart.

In fact, having multiple hearts is pretty much unheard of in mammals, or even in vertebrates.

Mammals’ circulatory systems have no need for multiple hearts, and horses are no different.

In fact, despite what you might think, many smaller animals are actually the ones who need multiple hearts.

As I said, there are very few vertebrates with multiple hearts, but several aquatic creatures. Octopuses, for example, have three hearts; one to pump blood around the body, and the other two hearts to pump blood to the gills to take up the oxygen.

The same is true of several species of fish, too.

So, as you can see, animals typically have multiple hearts if they need to process oxygen underwater.

Horses do not have gills, as you won’t be surprised to learn.

Therefore, all they need is their one heart, however bigger than ours it might be, to pump blood to all their extremities.

But what about heart chambers?

You might think that would be a better indication of how large a creature’s heart is, relative to ours.

Our own hearts have four chambers, so how many do horses have?

How many heart chambers do horses have?

A horse’s heart has four chambers, just like ours.

Horse’s hearts are much more similar to ours than you might imagine!

A horse’s heart has two atria chambers on the upper half of their heart, and the two lower chambers are the left and right ventricles—just like ours!

Again, the chambers themselves are of course bigger.

They’re wider to pump more blood through, but there aren’t more of them.

In many ways, a horse’s heart is different from ours, but it’s also almost like a scaled-up version of our own hearts.

The main way they differ is how the rest of the body aids circulation.

What is the frog on a horse’s hoof?

On the underside of a horse’s hoof, they have a small, V-shaped indent.

If the horse is standing on soft footing (and is not wearing a horseshoe), then that triangular indent should touch the ground.

It extends mid-way from the heels towards the toe, covering a quarter of the bottom of the foot.

Each time the frog makes contact with the ground while the horse is walking, it pumps blood up the horse’s leg and back towards the heart.

It’s really important that their extremities are able to support themselves and aid circulation in this way, since horse’s limbs are so long.

This is one of the main ways a horse’s circulatory system differs from ours, and is one of the reasons they don’t need more than one heart.

So, how big is a horse’s heart to pump all that blood around that huge body?

How big is a horse’s heart?

Naturally, the size of the heart will vary by the size of the horse, but it will weigh roughly 1% of the overall bodyweight.

This is quite a lot for a single organ, but the heart is of course one of the most important organs in the body.

The average horse’s heart weighs about 8-10lbs, and can pump as much as 7 to 10 gallons of blood a minute at rest.

During exercise, race and show horses can pump as much as 65 gallons per minute around their bodies.

So, this really is the simplest answer to why horses have only one heart.

They don’t need multiple hearts when the one they have makes up a significant portion of their overall bodyweight!

So, horses’ hearts aren’t like ours, except that they have the same amount.

They have very different circulatory systems on the whole to deal with the extra weight and extremity, but in essence the principles are the same.

Horses don’t have multiple hearts to deal with the problem, their bodies have just adapted and developed in many other ways.

Horse hearts need to be able to pump lots of blood into long extremities, so the extra muscle power is really essential.