Zombies, à la the walking dead, don’t exist in the real world, but they have been a big part of pop culture and show up time and again in history and folklore.

As portrayed in the classic 1968 film “Night of the Living Dead,” zombies are lumbering, flesh-eating corpses. Some say this film reinvented zombies, who were shown in earlier films such as 1932′s “White Zombie” as “beings whose brains had been zapped by some ‘master’ who was then able to control their actions,” according to the University of Michigan website.

Zombies are even mentioned in Haitian folklore, with the Haitian word “zombi” meaning “spirit of the dead.”

While no scientific evidence suggests human zombies exist, there are plenty of zombies in the animal kingdom.

By watching 16 infected ants bite down, the researchers, who describe their findings in the journal BMC Ecology, found that the ants’ last bites took place around Noon, indicating they are synchronized to either the sun or a related cue, like temperature or humidity.

Recent research in a Thai rain forest showed how a parasitic fungi, a species of Ophiocordyceps, forces an infected ant to wander drunkenly over the forest’s low leaves before clamping its jaws around the main vein on the underside of a leaf in an ant-zombie graveyard.

Zombie caterpillars have also been spotted by scientists, with one study revealing the mastermind behind the gypsy moth caterpillar’s zombie-like run for treetops once infected with a virus. Turns out, a single gene in the virus turns the caterpillars into tree-climbing zombies. Once up high in the trees, the caterpillars die and their bodies liquefy, raining deadly “zombie” virus onto their brothers and sisters below.

Via LiveScience