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.

20 Black-and-White Facts About Penguins

iStock/fieldwork
iStock/fieldwork

Happy Penguin Awareness Day! To celebrated, here are a few fun facts about these adorable tuxedoed birds.

1. All 17 species of penguins are found exclusively in the Southern Hemisphere.

A group of penguins on an iceberg.
iStock/axily

2. Emperor Penguins are the tallest species, standing nearly 4 feet tall. The smallest is the Little Blue Penguin, which is only about 16 inches.

Three emperor penguins
iStock/Fabiano_Teixeira

3. The fastest species is the Gentoo Penguin, which can reach swimming speeds up to 22 mph.

A gentoo penguin swimming underwater
iStock/chameleonseye

4. A penguin's striking coloring is a matter of camouflage; from above, its black back blends into the murky depths of the ocean. From below, its white belly is hidden against the bright surface.

Penguins swimming in the ocean
iStock/USO

5. Fossils place the earliest penguin relative at some 60 million years ago, meaning an ancestor of the birds we see today survived the mass extinction of the dinosaurs.

Emperor penguins with chicks
iStock/vladsilver

6. Penguins ingest a lot of seawater while hunting for fish, but a special gland behind their eyes—the supraorbital gland—filters out the saltwater from their blood stream. Penguins excrete it through their beaks, or by sneezing.

Penguin swimming in the ocean
iStock/Musat

7. Unlike most birds—which lose and replace a few feathers at a time—penguins molt all at once, spending two or three weeks land-bound as they undergo what is called the catastrophic molt.

Gentoo penguin chick molting
iStock/ChristianWilkinson

8. All but two species of penguins breed in large colonies of up to a thousand birds.

A colony of king penguins
iStock/DurkTalsma

9. It varies by species, but many penguins will mate with the same member of the opposite sex season after season.

Two chinstrap penguins
iStock/Legacy-Images

10. Similarly, most species are also loyal to their exact nesting site, often returning to the same rookery in which they were born.

Magellanic penguin nesting in the ground
iStock/JeremyRichards

11. Some species create nests for their eggs out of pebbles and loose feathers. Emperor Penguins are an exception: They incubate a single egg each breeding season on the top of their feet. Under a loose fold of skin is a featherless area with a concentration of blood vessels that keeps the egg warm.

Penguin eggs
iStock/Buenaventuramariano

12. In some species, it is the male penguin which incubates the eggs while females leave to hunt for weeks at a time. Because of this, pudgy males—with enough fat storage to survive weeks without eating—are most desirable.

A group of emperor penguins and chick
iStock/vladsilver

13. Penguin parents—both male and female—care for their young for several months until the chicks are strong enough to hunt for food on their own.

Penguin chick and parent on a nest
iStock/golnyk

14. If a female Emperor Penguin's baby dies, she will often "kidnap" an unrelated chick.

Three emperor penguin chicks
iStock/AntAntarctic

15. Despite their lack of visible ears, penguins have excellent hearing and rely on distinct calls to identify their mates when returning to the crowded breeding grounds.

Gentoo penguins
iStock/Goddard_Photography

16. The first published account of penguins comes from Antonio Pigafetta, who was aboard Ferdinand Magellan's first circumnavigation of the globe in 1520. They spotted the animals near what was probably Punta Tombo in Argentina. (He called them "strange geese.")

A group of magellanic penguins on the seacoast
iStock/encrier

17. An earlier, anonymous diary entry from Vasco da Gama's 1497 voyage around the Cape of Good Hope makes mention of flightless birds as large as ducks.

A cape penguin in South Africa
iStock/ziggy_mars

18. Because they aren't used to danger from animals on solid ground, wild penguins exhibit no particular fear of human tourists.

Man videotaping a penguin in Antarctica
iStock/Bkamprath

19. Unlike most sea mammals—which rely on blubber to stay warm—penguins survive because their feathers trap a layer of warm air next to the skin that serves as insulation, especially when they start generating muscular heat by swimming around.

Penguin swimming in the ocean
iStock/Musat

20. In the 16th century, the word penguin actually referred to great auks (scientific name: Pinguinus impennis), a now-extinct species that inhabited the seas around eastern Canada. When explorers traveled to the Southern Hemisphere, they saw black and white birds that resembled auks, and called them penguins. 

13 Fascinating Facts About Pallas’s Cats

iStock.com/NEALITPMCCLIMON
iStock.com/NEALITPMCCLIMON

Far across the world, an elusive—and adorable—wildcat called the Pallas’s cat (also known as the manul) roams the grasslands and steppes of Central Asia and Eurasia. Get to know the flat-faced, furry kitty, which has been featured in memes and viral videos and recently received its own wildlife preserve in Asia’s Altai Mountains.

1. It's named after naturalist Peter Pallas.

German naturalist Peter Pallas first described the furry wildcat in 1776. He named the kitty Felis manul, and theorized that it was an ancestor of the Persian cat, due to its round face, luxurious coat, and stocky body. (He was wrong.)

2. Its scientific name means "ugly-eared."

Later on, the cat's scientific name was changed from Felis manul to Otocolobus manul—not exactly the most flattering moniker, since Otocolobus is Greek for “ugly-eared.”

3. Its unusual ears come in handy.

Some may consider the Pallas’s cat’s ears to be ugly, while others might think they’re adorable. Arguments aside, the cat’s round ears—which sit flat on the sides of its head—are one of the feline's most distinguishing features. As Crystal DiMiceli, a former wild animal keeper at Brooklyn's Prospect Park Zoo, explains in the above video, having low-positioned ears helps the cat conceal itself—they don’t poke up to reveal the animal's position while it's hiding or hunting.

4. It has a dense, plush coat.

The coat of the Pallas's cat is its true crowning glory. It’s longer and denser than any other coat belonging to a member of the Felid species (growing in even heavier in the winter), and the undercoat on its belly is twice as long as the fur covering the rest of its body. The shade ranges from silvery grey during the winter to a darker, red-toned hue during warmer months. (Some cats are also red, particularly in Central Asia.) Its broad head is streaked and speckled with dark markings, and its bushy tail is banded with stripes and a dark tip. These markings tend to appear darker during the summer.

5. Its fur blends with its habitat, which conceals it from predators.

Pallas's cats live in areas ranging from Pakistan and northern India to central China, Mongolia, and southern Russia. According to Wild Cats of the World, by Luke Hunter, its body isn’t adapted for snow, so it sticks to cold, arid habitats—particularly grassy or rocky areas, which help conceal it from predators—at elevations of around 1500 to nearly 17,000 feet. The stocky cat isn’t a fast runner, so when it senses danger, it freezes and crouches flat and motionless on the ground, and its fur helps it blend in with its surroundings.

6. Pallas's cats aren't fat—they're just furry.

Pallas's cats typically weigh less than 12 pounds, and they’re usually only 2 feet or less in body length—meaning they’re not that much larger than an ordinary house cat. Yet their dense coat of fur makes them appear much larger.

7. Their pupils are round instead of vertical.

Pallas's cats do share one feature in common with larger wildcats, like lions and tigers: their eyes. Their pupils are round, whereas a house cat's pupils are vertical and slit-shaped. Wondering why some cats have round pupils while others have vertical ones? A 2015 study conducted by researchers at the University of California, Berkeley found that animals’ pupil shapes might indicate their role in the predator/prey food chain. They analyzed 214 species of land animals (including cats), and noted that species with vertical pupils tended to be ambush predators that were active during both day and night. In contrast, species with vertical pupils were often “active foragers,” meaning they chase their prey. Also, predators that are closer to the ground, like house cats, were prone to vertical pupils, whereas larger wildcats had round ones. Pallas’s cats are small, and they are primarily ambush hunters, so the jury’s still out on whether the study's findings hold true for all creatures.

8. They subsist mostly on pika.

A Pallas's cat sticks its tongue out
iStock.com/Nikolai Vakhrushev

Pallas's cats are ambush hunters and spend much of their time hunting pika, a small mammal, and other critters like gerbils, voles, hares, ground squirrels, birds, and young marmots. Pika typically make up more than 50 percent of the cat's diet. 

9. They may be distantly related to the leopard cat.

Peter Pallas thought the animal was related to the Persian cat. (We think it looks like a Maine Coon and a Scottish Fold had a baby and weaned it on steroid milk.) However, experts have uncovered evidence that the wildcat’s nearest—yet still pretty distant—relative might be the leopard cat.

10. They's not social animals.

The Pallas's cat is notoriously elusive and spends much of its time hiding in caves, crevices, or abandoned burrows.

11. They don't seem to like each other much.

A pair of Pallas's cats size each other up
iStock.com/eli77

Pallas's cats may be adorably fluffy, but they aren’t the world’s sweetest, most cuddly creatures. In fact, they’re very aggressive. Case in point: In The Wild Cat Book, authors Fiona and Mel Sunquist recount an anecdote provided by Bill Swanson, the Cincinnati Zoo’s director of animal research. Zookeepers thought that a litter of newborn Pallas's cats were having difficulty breathing, but “when they listened closely, they realized that the noise they were hearing was the kittens growling and hissing at each other—before they had even opened their eyes!"

12. Their mating period is brief.

Pallas’s cats mate between December and March; the females typically give birth between the end of March and May, after a gestation period of 66 to 75 days. Pallas’s cats usually give birth to three or four kittens, but litters can sometimes have as many as eight kittens. Kittens become independent by four to five months, and when they reach nine to 10 months, they’re mature enough to reproduce. 

13. They're classified as "near-threatened."

It's estimated that Pallas's cats can live up to six years in the wild, but because of predators and other dangers, their lifespan is likely to be half this length. In captivity, they’ve been known to survive for nearly 12 years.

In 2002, the International Union for Conservation of Nature classified the Pallas’s cat as “near-threatened,” and that status remains today. Many factors contribute to their low numbers, including farming, agricultural activities, mining, and poisoning campaigns aimed at reducing pika and marmot populations. They're also often killed in traps meant for wolves and foxes, or by domestic dogs. And despite international trading bans and legal protections in some countries, they're often hunted for their fur. (The cat's fat and organs are also used to make traditional medicines.) 

Scientists don't have enough data to estimate the Pallas’s cat's population size, but due to their scarcity and the many threats they face, experts believe that their numbers have dropped by 10 to 15 percent over the past decade or so. To better understand—and protect—the animal, an international team of conservationists recently secured a 12-mile swath of land in Sailyugemsky Nature Park, which lies in the Altai Mountains between Kazakhstan and Mongolia, as a sanctuary for the rare cat. There, they hope to monitor its population, study its habitat, and build a database of information detailing encounters with it. 

Additional Source:
Wild Cats of the World by Luke Hunter

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