That’s an interesting question! When we think of “hearts”, we usually imagine the human heart that pumps blood throughout our bodies. But some living things actually have multiple hearts. Let’s explore some possibilities of creatures that might have 4 hearts.
Insects
Some insects like cockroaches have multiple hearts. Cockroaches have one main heart that pumps blood, plus they have 13 additional “accessory pulsatile organs” that serve as extra hearts to circulate blood to their legs and wings. So in total, cockroaches have 14 hearts! Other insects like grasshoppers and crickets also have accessory hearts.
Cockroach Heart Anatomy
Here’s a more detailed look at the anatomy of a cockroach’s circulatory system:
| Heart Name | Location | Function |
|---|---|---|
| Dorsal vessel | Runs along top of body | Main heart that pumps hemolymph |
| Lateral hearts | Sides of body | Circulates hemolymph to antennae and legs |
| Accessory pulsatile organs | Base of legs and wings | Circulates hemolymph to extremities |
As you can see, cockroaches have one main heart plus up to 13 extra hearts for circulating blood! So while they don’t exactly have 4 hearts, they do have way more than humans.
Octopuses
Here’s another possibility – octopuses have 3 hearts! They have one main systemic heart that pumps blood to the body, plus two smaller branchial hearts that pump blood to the gills. So an octopus has 3 hearts, close to 4.
Octopus Heart Anatomy
| Heart Name | Location | Function |
|---|---|---|
| Systemic heart | Between the digestive gland and gills | Pumps blood to body |
| Branchial hearts | Base of each gill | Pump blood through gills |
The systemic heart does most of the circulatory work, while the smaller branchial hearts focus specifically on the gills. While not exactly 4 hearts, the octopus comes close with its 3 heart circulatory system!
Giant Tube Worms
Giant tube worms are marine invertebrates that live near hydrothermal vents deep in the ocean. They do not have a typical circulatory system, but rather have a unique organ called a “trophyosome” that contains hemoglobin and acts as a kind of “diffuse heart.” The trophyosome runs the length of the giant tube worm’s body and contracts rhythmically to circulate nutrients and oxygen, similar to a heart.
Some studies have suggested that the trophyosome may actually act as multiple separate hearts along the body. In some species, it seems the trophyosome has distinct sections that pulse at different rates, effectively acting like multiple hearts down the length of the worm. Scientists have proposed some species may essentially have 4 or more “hearts” in the form of independently beating sections of the trophyosome.
Giant Tube Worm Anatomy
| Heart Name | Location | Function |
|---|---|---|
| Trophyosome | Runs length of body | Performs “pulse” to circulate nutrients |
| Potentially 4+ distinct sections | Throughout the trophyosome | May act like separate hearts |
While more research is needed, some giant tube worms may essentially have 4+ hearts along their trophyosome organ that “pulse” to circulate nutrients throughout their bodies.
Snails
Snails are another invertebrate that has an unusual circulatory system. Most snails have an open circulatory system with one main heart. But some larger snails have a closed circulatory system that includes two “auricles” that are actually beating chambers that act as extra hearts!
For example, the giant garden snail has one ventricle heart plus two auricles considered to be “accessory hearts.” So in total, a giant garden snail has three beating chambers or “hearts” that work together to circulate blood.
Garden Snail Heart Anatomy
| Heart Name | Location | Function |
|---|---|---|
| Ventricle | Main body mass | Main heart that pumps blood |
| Auricles | Near ventricle | Accessory hearts that pump blood |
So while not exactly 4 hearts, the multiple beating chambers in snails are another example of an invertebrate with extra “hearts” beyond the standard single vertebrate heart!
Cuttlefish
Cuttlefish are cephalopod molluscs like octopuses. They also have three hearts – one main systemic heart, and two smaller branchial hearts near the gills. The branchial hearts pump blood through the gills, while the systemic heart circulates blood throughout the body.
However, when a cuttlefish swims, the systemic heart actually stops beating! The rapid swimming motion circulates the blood instead. Meanwhile, the branchial hearts continue pumping at a higher rate to provide oxygen to the tissues. So in essence, cuttlefish could be considered to only use their “2 hearts” when swimming quickly.
Cuttlefish Heart Anatomy
| Heart Name | Location | Function |
|---|---|---|
| Systemic heart | Between gills | Pumps blood to body |
| Branchial hearts | Near each gill | Pump blood through gills |
So while cuttlefish don’t normally use exactly 4 hearts, their triple-heart circulatory system is the closest match found so far among the animals we’ve explored!
Conclusion
After this exploration of some unique circulatory systems in the animal kingdom, we find that the closest organisms to literally having 4 hearts are:
- Octopuses with 1 main heart + 2 branchial hearts (3 total)
- Some snails with 1 main ventricle + 2 auricle accessory hearts (3 total)
- Cuttlefish with 1 main heart + 2 branchial hearts (3 total)
- Giant tube worms with potentially 4+ independently pulsing sections of a “trophyosome” organ acting like multiple hearts
While we don’t find any perfect 4-hearted matches, these examples showcase how diverse circulatory systems can be across different types of animals. Clearly, Mother Nature has more than one way to pump blood and keep organisms alive!
We explore beyond the standard single human heart to find examples like insect accessory pulsatile organs, mollusc branchial hearts, and annelid trophyosomes. This demonstrates the amazing creativity and variety in the evolution of anatomical systems like circulation. While the human heart is remarkable, it is humbling to realize it is just one implementation out of many circulating marvels in the natural world.
So in summary, while no single perfect “4 heart” example emerges from this investigation, we gain an appreciation for the diversity and intricacy of circulatory systems. There are many ways to build a biological pump! So although we don’t find a literal match for the question “What has 4 hearts?”, we explore some fascinating alternatives that really get the blood flowing!
