FRANK'S FACTS

🐙 Animal Facts

The animal kingdom is where nature keeps its wildest ideas, and Frank has filed forty-three of the finest here — every one verified, none of them "a guy at the bait shop told me." From three-hearted octopuses to bees with a government-certified dance language, these are the facts that make you look at the family dog and wonder what else he isn't telling you.

Under the Sea

• FACT #1 An octopus has three hearts and blue blood. Two hearts pump blood through the gills, one serves the rest of the body — and the copper-based pigment in its blood turns it blue instead of red. The main heart actually stops beating when the octopus swims, which is one reason they prefer to crawl.
• FACT #2 Most of an octopus's neurons aren't in its head. Roughly two-thirds are spread through its eight arms, so each arm can taste, touch, and problem-solve semi-independently. (Frank says: imagine your left arm having opinions.)
• FACT #3 The peacock mantis shrimp throws one of the fastest punches in nature — its club-shaped limb accelerates so violently that the water around the strike briefly vaporizes into a collapsing bubble, delivering a second mini-blow. Aquariums have learned to keep them away from glass they're fond of.
• FACT #4 Sea otters sometimes hold paws while sleeping, and wrap themselves in kelp, so they don't drift apart on the current. It is exactly as practical as it is adorable.
• FACT #5 The Greenland shark may be the longest-lived vertebrate on Earth. A 2016 study that dated proteins in the sharks' eye lenses estimated some individuals were well over 270 years old — and one large female may have been close to 400. (Science, 2016)
• FACT #6 The so-called "immortal jellyfish," Turritopsis dohrnii, can reverse its own life cycle: when injured or starving, the adult can revert to its juvenile polyp stage and start growing up all over again.
• FACT #7 Among seahorses, it's the father who gets pregnant. The female deposits her eggs in the male's brood pouch, and he carries them until he gives birth to the tiny fry.
• FACT #8 The blue whale is the largest animal known to have ever lived — bigger than any dinosaur we've found. Its heart alone can weigh around 400 pounds. (Frank says: and you complain about carrying groceries.)
• FACT #9 Every clownfish is born male. They live in strict pecking orders, and when the dominant female of a group dies, the top-ranking male changes sex and takes her place. The movies skipped that part.
• FACT #10 An electric eel can discharge a jolt of several hundred volts — more than enough to stun prey and to make researchers very careful with their nets.
• FACT #11 Sharks are older than trees. Sharks have prowled the oceans for roughly 450 million years, while the earliest known trees appeared tens of millions of years later.
• FACT #12 Horseshoe crab blood is baby blue and medically precious: it clots in the presence of certain bacterial toxins, so for decades it has been used to test that vaccines and medical equipment are contamination-free.

Feathered Friends

• FACT #13 Owls can't move their eyes. Their eyes are long tubes fixed in the skull — so instead, an owl can swivel its head about 270 degrees, thanks to extra neck vertebrae and specially routed blood vessels.
• FACT #14 Owl flight is nearly silent. Comb-like serrations on the leading edge of their wing feathers break up the air and hush the "whoosh" — a trick engineers have studied to design quieter fan blades.
• FACT #15 The Arctic tern commutes from the Arctic to the Antarctic and back every single year. Tracking studies have clocked round trips of more than 40,000 miles — the longest known migration of any animal.
• FACT #16 Hummingbirds are the only birds that can truly fly backwards, and their hearts can beat more than a thousand times a minute during flight.
• FACT #17 Emperor penguins are world-class divers: they've been recorded plunging more than 1,500 feet deep and holding their breath for over 20 minutes while hunting.
• FACT #18 Crows recognize individual human faces — and hold grudges. Researchers at the University of Washington who trapped crows while wearing a particular mask found the birds scolding that mask for years afterward, and teaching their friends to do the same.
• FACT #19 The wandering albatross has the largest wingspan of any living bird — over ten feet in big individuals — and can glide for hours over the open ocean barely flapping at all.
• FACT #20 Flamingos aren't born pink. Chicks hatch gray, and the famous color comes from pigments in the shrimp and algae they eat. Change the diet, and the pink fades.
• FACT #21 An ostrich's eye is bigger than its brain. Each eye is about two inches across — the largest of any land animal. (Frank says: no comment. The ostrich knows what it did.)
• FACT #22 The kiwi lays one of the largest eggs relative to body size of any bird — a single egg can amount to roughly a fifth of the mother's weight.
• FACT #23 Australia's superb lyrebird is nature's tape recorder: it convincingly mimics other birds and has been documented imitating camera shutters, car alarms, and chainsaws.

Mammals Behaving Oddly

• FACT #24 Wombats produce cube-shaped droppings — see the plaque above. It bears repeating, and Frank will repeat it at any dinner party that will have him.
• FACT #25 A giraffe's neck contains the same number of vertebrae as yours: seven. Each of the giraffe's is simply enormous — up to ten inches long.
• FACT #26 Bats are the only mammals capable of true powered flight. Flying squirrels merely glide; bats actually earn the ticket.
• FACT #27 The platypus lays eggs, the males carry venomous spurs on their hind legs, and the whole animal has no true stomach — food passes from gullet to intestine. When the first specimen reached Europe, scientists suspected a hoax. (Frank sympathizes with those scientists.)
• FACT #28 Elephants can't jump. An adult elephant's legs are built like load-bearing columns, and at several tons, all four feet stay respectfully on the ground.
• FACT #29 Sloths visit the bathroom about once a week — and they climb all the way down from their tree to do it, one of the most dangerous errands in a sloth's calendar.
• FACT #30 A polar bear's skin is black, and its fur isn't truly white — the hairs are hollow and translucent, scattering light to look white against the snow.
• FACT #31 Dolphins sleep with one half of their brain at a time, keeping one eye open, so they can keep surfacing to breathe. It's called unihemispheric sleep, and Frank envies it on busy weeks.
• FACT #32 Cheetahs can't roar — they purr, chirp, and even meow. What they can do is sprint: a cheetah named Sarah at the Cincinnati Zoo was clocked at over 60 miles per hour.
• FACT #33 Horses cannot vomit. A powerful one-way valve at the entrance to the stomach means food generally goes in and only in — which is why colic is such serious business for a horse.
• FACT #34 Naked mole rats shrug off conditions that would finish most mammals: in one laboratory study they survived a full 18 minutes with no oxygen at all by switching their metabolism to run on fructose, plant-style. (Science, 2017)
• FACT #35 Cows appear to have best friends. Research measuring heart rates and stress hormones found cattle were measurably calmer when penned with a preferred companion than with a stranger.

Tiny Titans

• FACT #36 Tardigrades — "water bears" smaller than a millimeter — have survived direct exposure to the vacuum and radiation of open space, in a 2007 European experiment that flew them into orbit and brought some home alive.
• FACT #37 Ants routinely carry objects many times their own body weight, thanks to the mechanics of being small: muscle strength scales down far more slowly than weight does.
• FACT #38 Honeybees tell each other where the flowers are by dancing. The "waggle dance" encodes both direction and distance to the food, and decoding it helped win Karl von Frisch a Nobel Prize in 1973.
• FACT #39 A single worker honeybee produces only about one-twelfth of a teaspoon of honey in her entire lifetime, by beekeepers' common reckoning. Every jar is a stadium's worth of tiny careers. (Frank tips his hat before every slice of toast.)
• FACT #40 Dragonflies may be the deadliest hunters on Earth by success rate: studies have found they capture the prey they target more than 90 percent of the time. Lions should take notes.
• FACT #41 Butterflies taste with their feet. Sensors on their legs let a female sample a leaf the moment she lands, to check whether it's the right plant for her eggs.
• FACT #42 The axolotl, a permanently juvenile Mexican salamander, can regrow entire lost limbs — and repair its spinal cord, and parts of its heart and brain — without a scar.
• FACT #43 Fleas are champion jumpers, leaping many dozens of times their own body length in a single bound, powered by a spring-loaded pad of elastic protein in their legs.

That's the animal shelf — for now. Frank files new specimens most weeks, and the best ones go out first in Frank's Five. Next stop: the Science Facts shelf »

No animals were exaggerated in the making of this page. ★