RED RIDING HOOD thought the wolf had big ears. She had no idea.
From bugs to elephants, many animals have evolved large ears as adaptations to hot environments or strategies for finding food.
The African elephant has the biggest ears of any living animal. These floppy appendages serve to quickly dissipate heat through the ears’ many blood vessels into the air.
The long-eared jerboa (seen in Mongolia's South Gobi Desert) was first recorded on film in 2007.
PHOTOGRAPH BY VALERIY MALEEV, NATURE PICTURE LIBRARY
Asian elephants live amid the shaded—and cooler—cover of the rainforest, and hence have smaller ears.
But their ears aren’t elephants’ only “ears.”
Both species of elephant can detect vibrations underground through their feet, enabling them to detect the sound of stampeding animals from miles away—a signal that predators may be near.
There are 33 species of this hopping rodent, native to the deserts of southern Mongolia and northwestern China.
The most oddly proportioned family member is the long-eared jerboa, first caught on film in the wild in 2007 during a Zoological Society of London expedition to the Gobi.
With ears that are two-thirds as long as its body, the animal has the largest ears relative to size in the animal kingdom.
Like the elephant and many other species, these giant ears help the jerboa release heat, a vital adaptation in high temperatures.
Large ears actually have little to do with echolocation, the bat's built-in sonar that sends out sound waves and detects the echo bouncing off a prey item, such as a moth.
Most echolocation is at a very high frequency, and large ears amplify more low-frequency sounds, like rustling prey, says Aaron Corcoran, a National Geographic Explorer and research assistant professor at Wake Forest University.
There are six species of jackrabbit in the western US, and some species have ears up to seven inches long—about a third of their body size.
Andrew Smith, emeritus professor in conservation biology at Arizona State University, says via email that he jackrabbit’s huge ears are best explained by Mark Twain.
In Roughing It, the author writes this desert dweller has “the most preposterous ears that ever were mounted on any creature but a jackass.”
Why such comical ears? You guessed it—to disspate heat.
The caracal, a long-legged wildcat, ranges from Africa to India and is known for large, sophisticated ears that allow it to locate prey in tall grasses.
While hunting, the predator moves its ears around like a radio antenna, honing in on critters moving underfoot. Unique ear tufts may then funnel sound down toward the ear before they pounce.
The serval, another small African wildcat, has huge, powerful ears that can detect rodents scurrying underground.
FENNEC FOXES: WHY ARE THEIR EARS SO BIG?
Fennec foxes are the smallest of the fox species ... but their ears can grow to be half the size of their bodies.
Bat-eared foxes of eastern and southern Africa particularly enjoy insects—termites make up 75 percent of their diet. So it’s no surprise their exceptionally oversize ears can hear termite colonies moving under the earth.
Fennec foxes’ huge ears both dissolve the heat of their North African habitat and allow them to hear insect prey burrowing into the sand.