Weird-Looking Animals and Why They Look That Way

That pink starburst is not a nose ornament but a hand for feeling the world. The star is 22 fleshy tentacles packed with more than 25,000 tiny touch sensors called Eimer's organs, all in less than a square centimeter, and it sweeps the soil so fast it blurs, touching up to 12 objects a second. The payoff is speed. Guinness lists this North American mole as the fastest-eating mammal, with a fastest recorded time of 120 milliseconds from finding a morsel to swallowing it. When the mole digs, the tentacles fold forward over the nostrils to keep soil out.

Blobfish The saggy pink face voted World's Ugliest Animal in 2013 is a photo of an injury. The famous specimen, nicknamed Mr. Blobby, was netted on a 2003 research expedition between Australia and New Zealand, and its tissues fell apart on the way up from the deep. At home, roughly 3,300 to 4,400 feet down, the blobfish looks like a big-headed tadpole, as the drawing here shows. It has no gas bladder, little muscle and a weakly built skeleton, and a layer of mostly watery tissue likely gives it structure and buoyancy. The softness that ruins it at the surface is part of how it lives comfortably in the deep sea.

Deep-sea anglerfish The glowing rod dangling over a female anglerfish's head, as on the humpback anglerfish pictured, is a fishing lure. It hangs just in front of her mouth, enticing smaller fish in the dark, and its tip glows thanks to bioluminescent bacteria that it gathers from the water as she ages. The stranger body plan belongs to the males. They are far smaller than females, usually have no lure, and in some species a male fuses into the female's body until he is little more than a sausage-like attachment. In a vast, empty ocean, holding on to the one mate you found makes a kind of sense.

The saiga's huge, mobile nose drapes over its mouth like a deflated trunk, and it is built for the steppe's extremes. Each nostril is a sac lined with mucous membranes, which may help filter dust out of the air in dry summers and warm and moisten frigid air before it reaches the lungs in winter. The nose has a social job too. Males make loud nasal roars that are thought to advertise their size and condition and help them win females. Seen in profile, with that muzzle hanging over the lips, the saiga looks like an antelope wearing a costume nose, yet every part of it earns its keep.

The male proboscis monkey of Borneo grows a huge, drooping nose, and it works as an advertisement. A 2018 study of these monkeys found that males with bigger noses tended to be heavier, had larger testes and kept more females in their harems. The nose also changes his voice. It enhances his calls through resonance, and larger nasal passages seem to produce deeper calls, so females and rivals can hear the size of the nose as well as see it. Females have much smaller noses, which makes a mixed group look almost like two different species.

The shoebill's bill really does resemble a wooden shoe: an enormous structure ending in a sharp, curved hook, with sharp edges that help it catch and eat prey. Its main food is lungfish, along with other fish and some amphibians and reptiles, and the bill is built to grab and hold them. That bill explains the bird's famous stillness. It hunts mostly by standing and waiting or wading slowly through African wetlands, then lunges forward in a full-body collapse onto its prey. It cannot collapse again straight away, so each strike has to count. Usually silent, it often clatters its bill instead.

Every odd part of Madagascar's aye-aye belongs to one foraging kit. It taps on wood with a slender, flexible, elongated middle finger, listening for hollow spaces under the bark where grubs hide, and its large, naked ears are thought to sharpen that hearing. Ever-growing incisors, coated with enamel only on the front, then gnaw through to the prey. In effect it fills the niche a woodpecker would. Sadly, the same spooky look has cost it: some people in Madagascar kill aye-ayes on sight as crop pests or bad omens.

Wrinkly, pink and almost hairless, the naked mole-rat looks unfinished, but it is dressed for life in underground tunnels. Its lips close behind its big front teeth, so it can dig with its incisors without getting dirt in its mouth. Workers form a digging line, one gnawing at the front while the others push the soil back. It is not quite naked: sensitive whiskers and hairs on the tail help it find its way in the dark. Unusually for a mammal, it cannot hold a steady body temperature, so colonies huddle together and bask in shallow, sun-warmed tunnels instead. Each colony is run by a single breeding queen.

Why would a shark flatten its head into a wide hammer? The best-tested answer is hunting by electricity. In experiments, hammerheads detected hidden prey 40% farther from their swimming path than sandbar sharks with ordinary heads, because the wide head carries electroreceptors across a broader sweep of seabed, like a metal detector. Other ideas have fared worse. The same research found the head stays level when the shark turns, ruling out the theory that it works as a steering wing. Vision is a likelier bonus: a 2009 study found the wide-set eyes give hammerheads far more binocular overlap in front of the head than sharks with pointed snouts.

Matamata With a flat, triangular head, a snorkel of a snout and a fringe of knobbly skin, the matamata hardly looks like a turtle at all. The snorkel lets it breathe at the surface without showing its body, so it can lie still on the bottom of slow-moving South American waters. The real surprise is the mouth. When a fish drifts close, the matamata opens its wide jaws so fast that the rush of water sucks the prey straight in, and it swallows the fish whole. Its jaws are too weak to seize or chew prey, and with suction doing the work, they never need to.

The axolotl's frilly crown is a set of feathery external gills, and they are a sign that this Mexican salamander never really grows up. It keeps larval features such as those gills and a finned swimming tail into its adult, breeding life, and in the wild it rarely, if ever, transforms into a land-dwelling form. Its home, Lake Xochimilco near Mexico City, is now little more than a scattering of canals and swamps, and the species is classed as critically endangered. Its other celebrated trick, regrowing lost body parts, has made this permanent youngster a laboratory favorite.

The smallest living armadillo wears its pale pink shell like a cape. Unlike other armadillos' armor, the shell is attached only along the back by a thin membrane, and its pink tint comes from blood vessels close to the surface. Its shape is all about digging. This burrower from the deserts and scrublands of central Argentina has big digging claws on its front legs, and an extra upright plate at the back of the shell gives it a blunt, flat rear end. Burrows and tunnels are its refuge from predators, which helps explain why this tiny animal is so rarely seen.

Sunda colugo Often called the flying lemur, the Sunda colugo is neither a lemur nor a true flier. It is a glider wrapped in its own cloak of skin: the membrane stretches around its whole body from the neck to the tips of the fingers and tail, turning it into a furry kite. That full-body membrane is why it looks so odd hanging from a trunk, and why it is so good in the air: colugos have been recorded gliding as far as 150 meters between trees in Southeast Asian forests. Its lower front teeth are split into fine combs, thought to help scrape up sap, strain fruit and flowers, and perhaps groom all that fur.

A male babirusa's upper tusks never enter his mouth. They grow upward, pierce straight through the top of the snout and curve back toward the forehead, which gives this Indonesian pig the look of an animal wearing its teeth as antlers. They are not much use as weapons. Males fight over females with their lower tusks, and the upper pair seems to shield the face during those bouts. On some islands rivals use them to lock and hold each other's tusks. The babirusa lives on Sulawesi and a few nearby islands.

Two oddities in one crocodilian. The gharial's long, slender snout, lined with more than a hundred razor-sharp teeth, is specialized for catching fish, and it grows thinner and longer with age as the animal turns to eating almost nothing but fish. Then there is the bulbous knob on the tip of an adult male's snout, called a ghara. It serves courtship, as a visual signal to females, a way to blow bubbles during mating and a means of making a loud buzzing sound. This river specialist of the Indian subcontinent was the first crocodilian classed as critically endangered.

The narwhal's unicorn horn is a tooth. Narwhals have just two teeth, and in males the left one usually erupts through the upper lip as a tusk that spirals to the left and can grow to 3 meters long. Most females keep both teeth hidden in the jaw, though either sex can grow one tusk or, rarely, two. Unlike most entries here, its purpose is still an open question. Examination of a tusk found about ten million nerve endings, so researchers suspect it has a sensory role, but its exact function remains unknown. People have long prized the tusks anyway, first as spear and harpoon tips and later as valuable trade goods.

For its body size, the Philippine tarsier has the largest eyes of any mammal, and those enormous eyes are its night-hunting equipment. It emerges after dark to catch insects in the rainforests of islands such as Bohol, Samar, Leyte and Mindanao. Two more odd features complete the hunter. Its head can rotate 180 degrees, letting it look behind itself while it clings to a branch. And it is named for its feet: two greatly elongated foot bones give it extra leverage for jumping, which powers the leaps of this tiny, long-limbed primate.

The platypus looks assembled from spare parts, but its duck-like bill is its main sense organ, not a beak. It carries receptors sensitive to pressure along with electroreceptors, and it needs them, because the platypus closes its eyes, ears and nostrils when it forages underwater. The bill is how this Australian animal finds its prey by feel and by electricity. The other surprises are hidden. Males have a sharp spur about 12 millimeters long on each ankle, linked to a venom gland, and females lay eggs, usually two at a time, a trait the platypus shares only with the echidnas among mammals.