1、Squids have doughnut-shaped brains.
(Note: this photo is not of a giant squid. Pictures of giant squids in their natural habitat are hard to come by! Please accept this cute photo of a regular squid instead.)
So giant squids have brains the shape of doughnuts. Not only that, but their esophagus runs directly through the hole in their brain. Because of this, squids have to bite their food into small pieces so the meal can fit through the esophagus. If the food is too big, it can scrape against their brain and cause damage. :(
2、Leeches have 32 brains.
A leech's internal structure is divided into 32 separate segments, and each of these segments has its own brain.
3、Sea squirts eat their own brains.
The life of a sea squirt is as follows: it comes into this world as an egg that quickly turns into a tadpole-looking thing. It has one eye, a spinal cord, a tail, and a primitive brain that helps it move around. Once it finds its forever home (ocean floor, rock, boat), it attaches itself to said home. It then proceeds to eat its own brain, absorbing its tadpole-like body, and eventually turning into this creature.
4、An ostrich's brain is smaller than its eyeball.
So, one ostrich eyeball is the size of a billiard ball (around two inches in diameter). Now imagine two of those in an ostrich's head. Its eyeballs are so large that there is only a little room for its brain. So because science is science and evolution is weird, an ostrich's brain is smaller than its eyes — which makes sense considering it runs in circles to "escape" from predators.
鸵鸟的眼球大约有一个台球那么大(直径约2英寸，5厘米)。现在想像一下，鸵鸟的头上有两个“台球”。 它的眼球太大鸵鸟眼睛受伤要怎么办了，所以大脑只有一点空间。 所以科学只是科学，进化则相对奇怪，鸵鸟的大脑比它的眼球要小——这也使它不属于“食肉动物”的范畴
5、Starfish don't have a centralized brain.
The starfish's anatomy is super fascinating. Starfish use sea water (instead of blood) to pump nutrients throughout their bodies. And its central nervous system is distributed throughout its legs (or arms, who am I to say?), so it technically doesn't have a localized brain.
6、Male and female stickleback fish have different size brains.
Male stickleback fish have bigger brains than their female counterparts. Scientists don't know exactly why this is, one theory is that because the male is responsible for impressing the lady fish, building the nest, and taking care of the eggs, they have developed bigger brains. (The female is only responsible for laying eggs and inspecting the male's nest. Listen, I don't know. I'm not a scientist so don't come at me with this.)
7、A sperm whale has the biggest brain of any mammal — but compared to its body size, its brain is actually teeny tiny.
Even though a sperm whale has the biggest brain of any animal, its brain is not exceptionally big compared to its massive body size. An average sperm whale's brain weighs 17 pounds. For comparison, a human's brain weighs around three pounds, or about two percent of its body weight. A sperm whale can reach up to 45 tons (90,000 pounds!) so their brain only accounts for 0.00019 percent of their body weight.
8、A spider's brain is so big that it spills into its legs.
A spider's brain is so gigantic that its head doesn't have room for it. All of that extra brain actually spills over into the spider's legs. Scientists believe that this might explain arachnids’ amazing ability to spin webs.
9、A killer whale shuts down half of its brain when sleeping.
Whales use half of their brains for sleeping and the other half for breathing. The part of the brain that controls breathing stays awake while the other half catches some z's. Not only that, but the whale keeps one eye open (on the side of the brain that's awake) and the other closed while sleeping. It's called unihemispheric sleep, and dolphins, beluga whales, and sea lions do it, too!
10、Woodpeckers have a super-strength skull to prevent brain injuries.
Just take a moment to picture a woodpecker slamming its face into a tree over and over and over. Well, because it does this as a way of life, it has a unique spongey skull and neck muscles that protect the brain from the repetitive impact. In addition to that, a woodpecker has a third eyelid to ensure its eyeballs literally don't pop out of its head.
11、Around two-thirds of an octopus's neurons are distributed in its arms and suckers, and not its brain.
An octopus is equipped with 500 million neurons. More than half of these neurons are located in the limbs an individual suckers, while the remaining neurons are in the central brain and optic lobes. This distribution of neurons makes it possible for them to do incredible things with their arms — like solve puzzles, open jars, and taste with their skin.
12、A cockroach can live for weeks without a head and brain.
Yeah, sorry. Bad news for all roach haters. It's not a myth that a cockroach can live without a head. If a roach were to lose its head, its body would seal off the wound (by blood clotting) and go about its business until it dies of starvation.
13、A certain type of fungus can take over an ant's brain, literally turning it into a zombie.
Here's what happens: a specific type of fungus relies on ants to complete its life cycle. This fungus is so advanced, though, that it won’t pick just any of the ant; it knows what specific ant to attack. So, you have an ant foraging for food, minding its own business, when it eats something with this fungus on it. The fungus immediately spreads throughout the body, releasing mind-controlling chemicals. These chemicals hijack the ant's central nervous system, forcing it climb up vegetation and latch onto leaves while the fungus finishes killing the body.
The fungus then grows outside of the dead ant's body, developing a long stalk outside of the head that will eventually infect more ants that come in contact with it, starting the cycle over again.
The animal kingdom is a wild place.