- Sea squirts (I know — just, why?) ᴇᴀᴛ 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 ᴇᴀᴛ its own brain, absorbing its tadpole-like body, and eventually turning into this crᴇᴀᴛure.
- Male and female stickleback fish have different size brains.
Male stickleback fish have bigger brains than their female counterparts. WOMP. Scientists don’t know exactly why this is, one theory is that beᴄᴀᴜsᴇ 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 ʟᴀʏɪɴɢ 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.)
- 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 beᴄᴀᴜsᴇ 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 ᴘʀᴇᴅᴀᴛᴏʀs.
- A ᴋɪʟʟer whale shuts ᴅᴏᴡɴ half of its brain when sleeping.
Whales use half of their brains for sleeping and the other half for brᴇᴀᴛhing. The part of the brain that controls brᴇᴀᴛhing 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 cʟᴏsᴇd while sleeping. It’s called unihemispheric sleep, and dolphins, beluga whales, and sea lions do it, too!
- A cockroach can live for weeks without a head and brain.
Yeah, sorry. Bᴀᴅ news for all roach haters. It’s not a myth that a cockroach can live without a head. If a roach were to ʟᴏsᴇ its head, its body would seal off the ᴡᴏᴜɴᴅ (by ʙʟᴏᴏᴅ clotting) and go about its business until it ᴅɪᴇs of sᴛᴀʀᴠᴀᴛɪᴏɴ.
- Woodpeckers have a super-strength sᴋᴜʟʟ to prevent brain ɪɴjᴜʀies.
Just take a moment to picture a woodpecker slamming its face into a tree over and over and over. Well, beᴄᴀᴜsᴇ it does this as a way of life, it has a unique spongey sᴋᴜʟʟ 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.
- A certain type of fungus can take over an ant’s brain, literally turning it into a ᴢᴏᴍʙɪᴇ.
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 wont pick just any ol’ ant; it knows what specific ant to ᴀᴛᴛᴀᴄᴋ. So, you have an ant foraging for food, minding its own business, when it ᴇᴀᴛs something with this fungus on it. The fungus immediately spreads thʀᴏᴜɢʜout the body, releasing mind-controlling chemicals. These chemicals ʜɪjᴀᴄᴋ the ant’s central nervous system, forcing it climb up vegetation and latch onto leaves while the fungus finishes ᴋɪʟʟing the body.
The fungus then grows outside of the ᴅᴇᴀᴅ ant’s body, developing a long stalk outside of the head that will eventually ɪɴfᴇᴄᴛ more ants that come in contact with it, starting the cycle over again. Dᴀᴍɴ, that’s ʀᴏᴜɢʜ.
- Around two-thirds of an octopus’s neurons are distributed in its arms and sᴜᴄᴋᴇʀs, 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 sᴜᴄᴋᴇʀs, while the ʀᴇᴍᴀɪɴing 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.
- 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…as if spiders weren’t ᴛᴇʀʀɪfʏing enough. Scientists believe that this might explain arachnids’ amazing ability to spin webs.
P.S. If you want an actual picture of a spider, you creep, Google it. I wanted to spare everyone the sight of an actual spider.
- Starfish don’t have a centralized brain.
The starfish’s anatomy is super fascinating. Starfish use sea water (instead of ʙʟᴏᴏᴅ) to pump nutrients thʀᴏᴜɢʜout their boᴅɪᴇs. And its central nervous system is distributed thʀᴏᴜɢʜout its legs (or arms, who am I to say?), so it technically doesn’t have a localized brain.
- Leeches have 32 brains.
A leech’s internal structure is divided into 32 separate segments, and each of these segments has its own brain. In addition to that, every leech has nine pairs of ᴛᴇsᴛᴇs — but that’s another post for another day.
- Squids have doughnut-shaped brains.
Soo giant squids have brains the shape of doughnuts. Not only that, but their esophagus runs directly thʀᴏᴜɢʜ the hole in their brain. Beᴄᴀᴜsᴇ of this, squids have to ʙɪᴛᴇ their food into small pieces so the meal can fit thʀᴏᴜɢʜ the esophagus. If the food is too big, it can scrape ᴀɢᴀɪɴsᴛ their brain and ᴄᴀᴜsᴇ ᴅᴀᴍᴀɢᴇ. 🙁
- A sᴘᴇʀᴍ whale has the biggest brain of any mammal — but compared to its body size, its brain is actually teeny tiny.
Even though a sᴘᴇʀᴍ whale has the biggest brain of any animal, its brain is not exceptionally big compared to its massive body size. An average sᴘᴇʀᴍ 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 sᴘᴇʀᴍ whale can reach up to 45 tons (90,000 pounds!) so their brain only accounts for 0.00019 percent of their body weight.