Animals do some pretty strange things. Giraffes clean their eyes and ears with their tongues. Snakes see through their eyelids. Some snails can hibernate for three years. But other weird animal tales are hogwash. Let’s find out how some of these myths started—and why they’re not true.

Myth: Ostriches bury their heads in the sand when they’re scared or threatened.

How It Started

It’s an optical illusion! Ostriches are the largest living birds, but their heads are pretty small. “If you see them picking at the ground from a distance, it may look like their heads are buried in the ground,” says Glinda Cunningham of the American Ostrich Association.

Why It’s Not True

Ostriches don’t bury their heads in the sand—they wouldn’t be able to breathe! But they do dig holes in the dirt to use as nests for their eggs. Several times a day, a bird puts her head in the hole and turns the eggs. So it really does look like the birds are burying their heads in the sand!

Myth: Opossums hang by their tails.

How It Started

Opossums use their tails to grasp branches as they climb trees. So it’s not surprising that people believe they also hang from branches.

Why It’s Not True

A baby opossum can hang from its tail for a few seconds, but an adult is too heavy. Besides, says Paula Arms of the National Opossum Society, that wouldn’t help them survive. “Why would they just hang around? That skill isn’t useful—there’s no point.”

Myth: Touching a frog or toad will give you warts .

How It Started

Many frogs and toads have bumps on their skin that look like warts. Some people think the bumps are contagious.

Why It’s Not True

“Warts are caused by a human virus, not frogs or toads,” says dermatologist Jerry Litt. But the wart-like bumps behind a toad’s ears can be dangerous. These parotoid glands contain a nasty poison that irritates the mouths of some predators and often the skin of humans. So toads may not cause warts, but they can cause other nasties. It’s best not to handle these critters !

Myth: Mother birds will reject their babies if they’ve been touched by humans.

How It Started

Well-meaning humans who find a chick on the ground may want to return the baby bird to the nest. But the bird is probably learning to fly and shouldn’t be disturbed. The tale may have been invented to keep people from handling young birds.

Why It’s Not True

“Most birds have a poorly developed sense of smell,” says Michael Mace, bird curator at San Diego Zoo’s Wild Animal Park. “They won’t notice a human scent.” One exception: vultures, who sniff out dead animals for dinner. But you wouldn’t want to mess with a vulture anyway!

Myth: Penguins fall backward when they look up at airplanes.

How It Started

Legend has it that British pilots buzzing around islands off South America saw penguins toppling over like dominoes when the birds looked skyward.

Why It’s Not True

An experiment testing the story found that penguins are perfectly capable of maintaining their footing, even if they’re watching airplanes. “But the reality isn’t funny,” says John Shears, who worked on the survey. “Low-flying aircraft can cause penguins to panic and leave their nests.”