Do Spiders Have Hearts? How Many Hearts Do Spiders Have?

Do spiders have hearts? Can they love?

Okay, okay – so this is not an article about how spiders feel or if they have emotions but it is an article that describes the anatomy of a spider, more specifically whether spiders have hearts and how their heart functions.

Spiders are amazing little creatures that are very intelligent and utilize their small brain capacity at amazing levels.

In order to utilize their high-functioning brains, they need a good internal system that functions smoothly and efficiently.

This is where their heart plays a major role.

In this article, you will learn all about whether spiders have hearts, what they look like, and how they function.

Let’s just jump right in!

Do Spiders Have Hearts?

Yes, spiders have hearts. Although they don’t have blood like humans and other animals, they have something similar to blood that is pumped through the heart called “hemolymph or haemolymph“, and this functions in a similar manner to blood.

Hemolymph does the same job as our blood by delivering clotting agents, oxygen, nutrients, and endocrines to various parts of the body.

Do Spiders Have Hearts?

Spider hearts are used to pump their “blood” to various parts of the body to ensure they are getting enough oxygen, getting all the nutrients they need, helping with clotting, and also helping with the hydraulics in their legs for limb movement.

A spider’s heart is located in a vulnerable position on its body on the front dorsal side of the abdomen in a cavity known as the pericardial sinus.

A spider heart is in a tube-shaped cavity that pumps hemolymph from back to front into arteries that feed the legs and central nervous system.

As a spider’s heart pushes fluid out, negative pressure in the sinuses is able to pull oxygen-rich hemolymph in from around its book lungs.

Spiders have an open circulatory system but they do not have veins to transport hemolymph throughout their bodies.

Instead, hemolymph is pumped through arteries into sinuses that surround the internal organs of the spider.

Do Spiders Have Heartbeats?

Not only do spiders have hearts, but they also have heartbeats. Their heart pumps hemolymph throughout their bodies to provide the oxygen and nutrients needed to survive.

Without a heartbeat, a spider’s heart would not be able to function properly and it would die.

A standard heartbeat of a spider ranges anywhere from 9 beats per minute all the way up to 125 beats per minute, depending on the size of the spider and its energy level.

Below is a diagram of the internal anatomy of a spider.

As you can see, spiders have hearts located on their abdomens at the top just above their intestines, which is an extremely vulnerable place for their hearts and not well protected.

Spider Anatomy - Internal
Original: John Henry Comstock Vector: Pbroks13 (Ryan Wilson), CC BY 3.0, via Wikimedia Commons

How Many Hearts Do Spiders Have?

Spiders only have one heart but it doesn’t look very similar to a human heart.

However, it does function in a similar manner as a human heart, pumping spider blood throughout the body while delivering oxygen and nutrients to various parts of the body.

A spider heart is not divided into chambers. Instead, it is just a long, simple tube that pumps hemolymph to various parts of a spider.

How Big Are Spider Hearts?

Spider hearts are not very big in mass, but do extend through most of the top part of the abdomen of a spider.

Below is a diagram of the external anatomy of a spider to give you an idea of where a spider’s heart is located from the external view.

As you can see from the diagram below, spiders have a lot of external parts associated with their anatomy and every part plays a role in how a spider moves and how a spider is able to hunt, catch prey, jump, and spin webs or tethers from their spinnerets.

Spider Anatomy - External

Their hearts play a major role in how each of these external parts of a spider functions.

What Does a Spider Heart Look Like?

As shown in the diagram above of the internal anatomy of a spider, spiders have hearts that look nothing like a human heart looks.

It is just a long and narrow tube that extends through much of the top part of the abdomen of a spider.

Some spiders have a heavily pigmented area just above the heart called the cardiac mark.

Because of this mark, it is easy to identify where spiders have hearts if they have this pigmentation.

Can Spiders Have Heart Attacks?

Although spiders have hearts and an aorta, they do not have veins or a closed circulatory system.

Due to this, it would be nearly impossible for a spider to have a heart attack due to clogs in its system.

A heart attack is typically due to clogged arteries or veins.

Although spiders have arteries for pumping blood, it is not part of a closed circulatory system and it is highly unlikely that arteries would get clogged and cause a heart attack in spiders.

Since they don’t have veins, they are safe from having a heart attack due to clogs in their veins.

So it would be difficult for one to suffer a heart attack since there is nothing to get clogged, in regard to veins.

Besides, they don’t eat a whole lot of butter or fat and stay pretty fit due to their active lifestyle.

So they have that going for them as well.

Do Tarantula Spiders Have Hearts?

All spiders have hearts and that includes tarantulas. A tarantula’s heart is similar to any other spider but after testing was conducted by researchers, they have found that tarantulas may have a heart that performs double beating.

Using an MRI, researchers were able to image a tarantula’s heart and that study revealed that a process known as double beating may be occurring.

Double beating is a distinct type of contraction that wasn’t considered in spiders until the study was performed.


After reading this article, you should now know that spiders have hearts.

While a spider’s heart is similar to the way a human heart functions, its system is a closed circulatory system.

Spiders have hearts that pump blood through the aorta and into sinuses located close to the internal organs of a spider.

Due to this closed system, it is highly unlikely that spiders can have heart attacks because their system is closed and does not have many functioning parts like veins to get clogged.

Although they have arteries that pump the blood to and from the heart, it is unlikely that spiders have heart attacks by clogged arteries and there are no known tests that can provide proof that spiders have heart attacks.

Thank you for checking out this article about spider hearts and how they function.

If you enjoyed this article about spider hearts, you will surely enjoy other articles about spider anatomy by checking out our section on “spider parts“.