A creature’s brain is a mass of nerve tissue that controls the rest of the body, the majority of animals have one brain. There are, however, several types of animals with multiple brains… so to speak. To clear up the confusion, it depends on how you look at it.
If you look at it anatomically, all animals have only one brain, but some species have sections (or hemispheres) known as ganglia, which function independently from the main brain. These ganglia can be split up into many different parts that operate independent of each other.
If you look at it in this manner, animals with such sections and hemispheres can be categorized as having multiple brains. This is because each ganglion functions autonomously.
There are several animals with more than one brain. So let’s dive right in and have a look at 10 animals with multiple brains, then a few rare cases and a couple of honorable mentions.
10 Examples of Animals with Multiple Brains
Most animals have one brains, some have more than one, and some animals have no brains at all. In the following list we’re looking at animals with more than one brain.
1. Leeches
- Scientific Name: Hirudinea
- Number of Brains: 32
Leech is an annelid, meaning that it belongs to a category of animals with segmented bodies. The leech’s body consists of 32 segments.
Each of the 32 segments has its own brain. Each brain has an independent neuronal ganglion that’s responsible for controlling the respective segment.
2. Octopus
- Scientific Name: Octopoda
- Number of Brains: 9
The octopus has 9 brains, one for each tentacle and one at the head.
The main brain resides at the head while the other brains are interconnected as fused ganglia, with each brain having its own set of neurons. With more than 500 million neurons, only 30 percent of them are located at its main brain.
Even though each ganglion doesn’t require permission from the central brain, the neurons on the separate brains are effectively functional. This allows for the processing of sensory inputs while amplifying senses.
The octopus’ limbs are not only sensitive to light and color, but they’re also very responsive to touch and temperature. Octopus are among the smartest animals after humans.
3. Gastropods (Snail or Slugs)
- Scientific Name: Gastropoda
- Number of Brains: 3
You must have encountered slugs in your backyard, crawling around your old wooden furniture. Or you’ve seen some of them lugging around a wet yard.
But, did you know these soft-bodied mollusks have three brains?
Despite being slow and prone to dehydration (hence the need to seek wet regions), snails have three ganglia pairs located at the esophagus.
The three brains include the buccal, cerebral, and pleural. The buccal controls the buccal cavity and the radula, both of which are used for feeding.
The cerebral is responsible for controlling limb movements, vision, and other sensory organs. And lastly, the pleural coordinates the mantle cavity, which is used for respiratory.
4. Squid
- Scientific Name: Teuthida
- Number of Brains: 3
A squid’s brain comes in three ganglia parts: the central brain and two optic lobes.
The fact that the brain’s dominance in functionality is optical shows how vision is vital to a squid. 80 percent is devoted to visual information.
The brain is doughnut-shaped and very small in size relative to the body ratio.
While the two optical lobes receive and process sensory information via the esophagus, the main brain controls the mantle, mouth, and movement.
5. Cockroaches
- Scientific Name: Blattodea
- Number of Brains: 2
When it comes to cockroaches, one of the brains resides inside the skull, while the second brain is located at its back, near the abdomen.
Because of the duo of brains, cockroaches have amplified sensitivity. For example, the insect’s response is 1/20th of a second.
I guess that’s why it’s super difficult squashing a cockroach using a slipper. By the time you lift the slipper, the cockroach is already gone.
6. Mosquitoes
- Scientific Name: Culicidae
- Number of Brains: 3
Mosquitoes are pretty much the same as cockroaches. The two insects rely on sensitivity to survive.
The mosquito’s main ganglia brain resides at its head while the other brains are located at the abdomen and wings.
The peripheral brains are effective at controlling the respective segments of the mosquito.
7. Cuttlefish
- Scientific Name: Sepiida
- Number of Brains: 3
Cuttlefish is a Cephalopod, meaning it belongs to the large mollusk sea animals such as squids and octopuses. The animal is known for its magic-like features and capabilities. The cuttlefish can change its appearance at will, mainly for camouflaging purposes.
It can also mimic rocks and floating vegetation at the bottom of the sea. Whenever danger looms, the cuttlefish can also swim off very fast and at incredible speeds. The cuttlefish can only achieve such feats due to its multiple brains.
The three brains operate independently and are assigned different roles, such as controlling movements, camouflaging, eating, and even computing functionalities.
Recent studies have shown that cuttlefish have episodic memory. As a result, the sea animal can remember previous experiences by associating sensations of events with time, location, emotions, and people.
8. Silkworm Moth
- Scientific Name: Bombyx
- Number of Brains: 11
The silkworm moth is mainly known for its larval stage form. At this phase, it eats up young plants before maturity for later harvest.
However, once the moth is all grown up, its adult form doesn’t live long. Its lifespan is only 5 to 10 days.
The silkworm moth operates on instinct only, thanks to its advanced brain. This allows the moth to survive its short lifespan without eating or drinking.
The eleven ganglia brains have different functionalities, such as learning and creating a defensive mechanism through its venom and developing spines that can puncture human skin.
A fun fact about silkworm moths is that their only goal as living organisms is finding a mate and reproducing.
9. Grasshoppers
- Scientific Name: Caelifera
- Number of Brains: 3
Without a doubt, grasshoppers have a swift reaction. And that’s attributed to its multiple brains. You can’t catch one empty-handed.
Its nervous system is made of ganglia of neurons. They’re connected by nerve cords running through body segments.
The body segments are divided into three major regions – head, abdomen, and thorax. The same applies to the ganglia brains.
10. Bumblebee
- Scientific Name: Bombus
- Number of Brains: 3
Although bumblebees have smaller and simpler brains compared to the human brain, those brans perform complex functions.
Bumblebees can use their brains to learn and recognize colors and patterns.
The insect can also find its way back home from many miles away. All this is attributed to its multiple brains.
2 brain hemispheres
Human Beings
- Scientific Name: Homo sapiens
- Number of Brains: 2
As the most advanced animals on the planet, human beings have a developed brain. While a human brain is only one, it has two hemispheres – left and right. This doesn’t mean we have two brains.
The only time human beings have multiple brains is when twins are born with conjoined heads. This is a very rare genetic anomaly.
Regarding functionalities of both brains, one tends to be more dominant than the other. Still, both brains are reliant on each other. And doesn’t cause too much confusion as is in snakes.
If one fails, the other brain may fail too.
Monkeys
- Scientific Name: Cercopithecidae
- Number of Brains: 2
A monkey’s brain isn’t far apart in similarities with the human brain. In the same manner we have two brain hemispheres — right and left—, so does a monkey.
However, while the two hemispheres of the human brain coordinate with each other, the monkey’s brain operates independently, but not entirely.
That’s why the two brains in monkeys have different roles; one for controlling its body and the other for controlling its tails.
Deformities
Turtles
- Scientific Name: Testudines
- Number of Brains: 2
In oddity markets, a double-headed turtle fetches lots of prices. It’s thought to have some form of good luck or something like that. Turtles are known to have large brains, which means their physiological capabilities are enhanced.
Basically, turtles don’t really have multiple brains. But due to polycephaly, a turtle may have two heads, thus two brains. The brains operate in coordination to control the turtle’s senses, movement, and hunger.
Compared to single-headed turtles, double-headed turtles experience challenges surviving in their ecosystem. That’s because of the complexities in communication between the two brains.
Still, the two brains work efficiently to make sure the body fulfills its needs.
Snakes
- Scientific Name: Serpentes
- Number of Brains: 2
This is the same case as turtles. While snakes have one brain, some are born with two. This scenario makes snakes unique in their own right.
Even though snakes with two heads are at a disadvantage, their sensitivity is heightened. Unlike cephalopods (octopus and squids), the snake’s brain isn’t divided into ganglia sections.
This means the brains are not entirely independent. The two brains rely on each other to control the body, which may end up causing confusion in communication.
For instance, both brains may sense the need for food and instruct the respective heads to seek food. This results in both heads competing for the same prey.
The same applies to directions. The two brains don’t have a coordinated communication to control motor and movement. This causes the snake to move in different directions.
Dogs
- Scientific Name: Canis lupus
- Number of Brains: 2
This is another rare case. Dogs with two brains are those with two heads, which means one is more dominant than the other.
The brains’ communication depends on how the dog was born. If the heads are attached at the spine, there’s less likelihood of confusion. That means the brains will operate independently.
Final Note
It’s worth noting that the animals mentioned above have multiple brains operating in the form of ganglia. This is where the brain’s functionality of control and coordination is NOT centralized. The different brains function independently and act separately. A fact that qualifies the animals as having multiple brains.
Patricia is a wildlife enthusiast that loves traveling and learning about wildlife all over North America and the world. Aside from being writer for Wildlife Informer, she’s an avid bird watcher as well as the owner of several pet reptiles. She enjoys visiting national parks and seeing new sights in her free time.