7 Impressive Animal Defense Mechanisms

NOAA Photo Library, Flickr // CC BY 2.0
NOAA Photo Library, Flickr // CC BY 2.0

The deep-sea squid known as Octopoteuthis deletron has a startling defense mechanism: When threatened, the squid attacks its predator and then pulls away, breaking off the tip of its own arm and leaving it behind as a diversion. As the arm continues to glow and twitch, the squid makes its escape.

But this squid isn't the only creature with a bizarre tactic for keeping itself alive. Here are several other animals with impressive defense mechanisms.

1. THE LIZARD THAT SHOOTS BLOOD FROM ITS EYES

The Texas Horned Lizard is a scary-looking creature. Brown, plump and perfectly camouflaged in its native sandy environment, its first line of defense is its spiky demeanor. If the sharp spikes and horns don't ward off predators, the lizard steps it up a notch and squirts a well-aimed stream of blood out of its eyes. The stream of blood, which can go as far as 5 feet, is mixed with a foul-tasting chemical that wards off predators. But this odd weapon comes at a cost: The lizard may release one-third of its total blood supply this way, amounting to 2 percent of its body mass. Unfortunately, its population numbers are dropping thanks to a threat that won't retreat after a well-aimed squirt: habitat loss due to rapid urbanization in the Lone Star State. 

2. THE HAIRY FROG THAT BREAKS ITS OWN BONES

Trichobatrachus robustus, aka hairy or horror frog

Emőke Dénes, Wikimedia Commons // CC BY-SA 4.0

What if every time you felt threatened, your first and only method of defense was to break your own bones and use them for weapons? Meet the hairy frog, a Central African species. When breeding, the male frogs develop thin strands of skin along the sides of their bodies that resemble hair. In theory, these strands also allow the frogs to take in more oxygen while they watch over their eggs. But what's really compelling about this frog is its ability to crack its own toe bones and push them through their skin to form sharp claws, which are great for warding off would-be attackers.

While it's not completely clear what happens to the bones after the threat of attack subsides, researchers believe the bones slide back under the skin when the frog's muscles relax.

3. THE NEWT THAT TURNS ITS RIBS INTO SPIKES

spanish ribbed newt

The hairy frog isn't the only amphibian that uses its bones for weapons. When attacked, the Spanish ribbed newt shifts its ribs forward at an angle and pushes them through its stretched skin. The resulting effect is a row of spikes on either side of its body. Like the hairy frog, the newt has to force the bones through its skin every time it is attacked, but the mechanism seems to cause little or no harm to the creature. Maybe one day it'll get its own robot protector: A team of researchers at the the Swiss university EPFL created a robotic salamander inspired by the newt, which they called the Pleurobot (after its scientific name, Pleurodeles waltl).

4. THE TERMITE THAT BLOWS ITSELF UP

Talk about taking one for the team. When under attack, a species of termites found in the French Guiana rain forests sends older worker bugs on suicide missions to defend the whole colony. These older bugs, no longer as useful to the pack as they once were, come equipped with "explosive backpacks" that, over a lifetime, fill with toxic crystals produced by glands in the abdomen. When mixed with salivary gland secretions, these crystals create a toxic liquid that explodes on enemies, paralyzing them and killing the worker at the same time. These termites aren't alone among insects in using a suicidal defensive tactic: When faced with a threat, an ant found in Borneo expands its abdomen until it ruptures, shooting out a toxic liquid

5. THE FISH THAT SLIMES ITS ENEMIES

Hagfish are eel-shaped marine animals with the incredibly useful ability to slime their enemies. When threatened, the hagfish emit a slime from their pores that, when mixed with water, expands into a gelatinous goo that can either trap predators or suffocate them by clogging their gills. The video above shows a hagfish being attacked 14 separate times by sharks and other big fish, and coming out completely unharmed. Each predator took one bite before immediately spitting the hagfish out and swimming away, gagging. The best time to encounter a hagfish is probably after it's emptied its slime glands withstanding such an onslaught; the glands take three to four weeks to refill.

6. THE SEA CUCUMBER THAT SHOOTS ORGANS OUT OF ITS ANUS

sea cucumber on coral reef
iStock

Sea cucumbers can seem pretty boring. There are some 1250 known species of these sedentary creatures in the world, and many of them do indeed look like cucumbers. But when it comes to survival, things get interesting. Like starfish and sea urchins, sea cucumbers are echinoderms, and they can regenerate lost body parts if necessary. This comes in handy when they're threatened. The sea cucumber will expel its internal organs, which are sticky and sometimes contain a toxic chemical that can kill predators. They don't have much of a defense against pollution though, which is a problem, because they're superstar ocean-floor cleaners.

7. THE OPOSSUM THAT PLAYS DEAD

possum playing dead in the grass
Tony Alter, Flickr // CC BY 2.0

You can't do a roundup like this without at least mentioning the opossum. We typically refer to this creature's infamous defense mechanism as "playing dead," but there's actually nothing playful about it; the act is completely involuntary. Under intense fear, opossums fall into a comatose-like state that can last for hours, long enough to convince any predator that the opossum is already dead. Also unappetizing: Fear causes these animals to emit a corpse-like smell that only adds to their act. Thank the opossum for providing some defense for us too: They eat venomous snakes and ticks, gobbling up to 4000 insects a week.

14 Cute Facts About Rabbits

iStock
iStock

Rabbits are much more than the cute, carrot-munching creatures pop culture makes them out to be. They can dig sophisticated tunnels, grow to weigh up to 22 pounds, and even eat their own poop. Here are some more facts worth knowing about the beloved mammals.

1. THEY CAN’T LIVE OFF CARROTS.

Rabbit eating carrots.
iStock

Cartoons suggest that rabbits can happily survive on a diet of carrots alone. But in the wild, rabbits don’t eat root vegetables—they’d much rather munch on greens like weeds, grasses, and clovers. That doesn’t mean you can’t give your pet some carrots as a snack from time to time, but don’t overdo it: Carrots are high in sugar and contribute to tooth decay in 11 percent of pet bunnies.

2. SOME ARE TODDLER-SIZED.

Flemish giant rabbit.
iStock

Not all rabbits are cute and tiny. Some, like the Flemish giant rabbit, grow to be downright monstrous. This rabbit breed is the world's largest, reaching 2.5 feet in length and weighing up to 22 pounds. Fortunately these giants are the gentle kind, which makes them popular pets.

3. BABY RABBITS ARE CALLED KITTENS.

Baby bunny in field.
iStock

Nope, not bunnies, technically. Another word for the young is kits. Mature females are known as does while adult males are called bucks. "Bunny," meanwhile, falls into the same category of cutesy terms as "kitty" and "doggy"—they're not scientific, but everyone will know what you mean.

4. THERE'S SOME TRUTH TO THE PHRASE "BREED LIKE RABBITS."

Two rabbits outside.
iStock

Rabbits really are a busy bunch. A rabbit is ready to start breeding at just 3 to 8 months old. Once they reach that point, they can copulate eight months out of the year every year for the rest of their 9- to 12-year lifespan. A doe's reproductive system doesn't follow cycles; instead, ovulation is triggered by intercourse. After a 30-day gestation period she'll give birth to a litter of about four to 12 kits.

5. THEY "BINKY" WHEN THEY'RE HAPPY.

Rabbit hopping outdoors.
iStock

If you spend enough time around rabbits, you may be lucky enough to witness one of the cutest behaviors in nature. A bunny will hop when it's happy and do a twist in mid-air. This adorable action has an equally adorable name: It's called a "binky."

6. THEY EAT THEIR OWN POOP.

Cute rabbit indoors.
iStock

This behavior, on the other hand, is significantly less adorable. After digesting a meal, rabbits will sometimes eat their poop and process it a second time. It may seem gross, but droppings are actually an essential part of a rabbit's diet: They even produce a special type of poop called cecotropes that are softer than their normal pellets and meant to be eaten. Rabbits have a fast-moving digestive system, and by re-digesting waste, they're able to absorb nutrients their bodies missed the first time around.

7. THEY GROOM THEMSELVES LIKE CATS.

Rabbit grooming itself.
iStock

Rabbits are remarkably hygienic. Like cats, they keep themselves clean throughout the day by licking their fur and paws. This means rabbits generally don't need to be bathed by their owners like some other pets.

8. THEY CAN'T VOMIT.

Rabbit eating grass in a field.
iStock

While a cat can cough up a hairball after a long day of self-grooming, a rabbit cannot. The rabbit digestive system is physically incapable of moving in reverse. Instead of producing hairballs, rabbits deal with swallowed fur by eating plenty of roughage that pushes it through their digestive tract.

9. THEY CAN SEE BEHIND THEM.

Rabbit in a field.
iStock

It's hard to sneak up on a rabbit: Their vision covers nearly 360 degrees, which allows them to see what's coming from behind them, above them, and from the sides without turning their heads. The trade-off is that rabbits have a small blind spot directly in front of their faces.

10. THEY ARE REALLY GOOD JUMPERS.

Rabbit hopping.
iStock

Those impressive back legs aren't just for show. Rabbits are built for evading predators in a hurry, and according to Guinness World Records, the highest rabbit jump reached 3.26 feet off the ground and the farthest reached nearly 10 feet. There are even rabbit jumping competitions where owners can show off their pets' agility.

11. THEIR TEETH NEVER STOP GROWING.

Rabbit chewing leaves.
iStock

Like human fingernails, a rabbit's teeth will keep growing if given the chance. A rabbit's diet in the wild includes a lot of gritty, tough-to-chew plant food that would eventually wear down a permanent set of teeth. With chompers that grow at a rate of up to 5 inches a year, any damage that's done to their teeth is quickly compensated for. The flip-side is that domestic rabbits who aren't fed abrasive foods can suffer from overgrown teeth that prevent them from eating.

12. THEY LIVE IN ELABORATE TUNNELS CALLED WARRENS.

Rabbit butt sticking out of burrow.
iStock

Rabbits don't end up in Wonderland when they go down the rabbit hole, but the place where they live is more complicated than you might expect. Rabbits dig complex tunnel systems, called warrens, that connect special rooms reserved for things like nesting and sleeping. The dens have multiple entrances that allow the animals to escape in a pinch, and some warrens are as large as tennis courts and extend 10 feet below the surface.

13. THEIR EARS HELP THEM STAY COOL.

Rabbit walking toward camera.
iStock

A rabbit's ears serve two main purposes. The first and most obvious is hearing: Rabbits can rotate their ears 270 degrees, allowing them to detect any threats that might be approaching from close to two miles away. The oversized ears also have the added benefit of cooling rabbits down on a hot day. More surface area means more places for body heat to escape from.

14. THEY'RE HARD TO CATCH.

Rabbit running outdoors.
iStock

If their eyes, ears, and powerful legs don't give them enough of a head start when avoiding predators, rabbits have even more tricks to rely on. The cottontail rabbit moves in a zig-zag pattern when running across an open field, making it hard to target. It also reaches a top speed of 18 mph—they really are "wascally wabbits."

Ice Age Wolf Pup and Caribou Mummies Discovered in Yukon

Government of Yukon
Government of Yukon

Officials in Canada recently announced that gold miners in Yukon territory unearthed a mummified wolf pup and caribou calf, both of which roamed the continent during the Ice Age, CBC News reports. The specimens were found preserved in permafrost in Dawson City in 2016, and researchers used carbon dating to determine that the animals are more than 50,000 years old.

While fossils from this period often turn up in the Yukon, fully intact carcasses are a lot rarer, Yukon government paleontologist Grant Zazula told CBC News. “To our knowledge, this is the only mummified Ice Age wolf ever found in the world,” Zazula said.

The caribou calf carcass—which includes the head, torso, and front limbs—still has its skin, muscle, and hair intact. It was found in an area that contains 80,000-year-old volcanic ash. Observed in a similar condition, the wolf pup still has its head, tail, paws, skin, and hair.

A caribou calf
Government of Yukon

Close-up view of the wolf club
Government of Yukon

These findings also hold special significance for the Tr’ondëk Hwëch’in First Nation, an indigenous group in the Yukon. “The caribou has fed and clothed our people for thousands of years,” Tr’ondëk Hwëch’in Chief Roberta Joseph said in a statement. “The wolf maintains balance within the natural world, keeping the caribou healthy. These were an amazing find, and it’s a great opportunity to work collaboratively with the Government of Yukon and our community partners.”

The Canadian Conservation Institute will be tasked with preserving the animal specimens, and the findings will be displayed in Dawson City until the end of the month. They will later be added to an exhibit at the Yukon Beringia Interpretive Centre in Whitehorse.

[h/t CBC]

SECTIONS

arrow
LIVE SMARTER