Which animal has the most elongated ears?

 In relation to the size of the body?

The long-eared jerboa, a desert rodent, has the biggest ears of any species when compared to its body size. (Photo credit: Getty Images/ullstein bild/Contributor) 

Which creature has the biggest ears? You might assume it's the elephant, and you'd be partially right. According to Mary Ellen Holden, a zoologist and mammologist at the American Museum of Natural History in New York City, the African elephant, as the largest living land animal, has the largest ears of any living animal. The long-eared jerboa (Euchoreutes naso), a nocturnal, insect-eating rodent that lives in China and Mongolia's deserts, has the largest ears in proportion to its body size.

From head to rump, the long-eared jerboa (rhymes with Samoa) measures about 4 inches (10 centimeters) (not counting its long tail). Its ears are 40 percent to 50 percent the length of its body, measuring 1.5 to 2 inches (3.8 to 5 cm) long.

According to Holden, it has the longest ears in the animal kingdom in relation to its body size. According to Holden, the African elephant's ears are about 4 feet (1.2 m) long on average, but that's just around 17 percent of their body length, which is about 20 to 25 feet (6 to 7.5 m).

The long-eared jerboa, which is rarely seen on tape, made headlines in 2007 after a video taken during a Zoological Society of London trip to Mongolia's Gobi Desert. According to the video description, the critter reminds expedition leader and conservation biologist Jonathan Baillie of Mickey Mouse in the desert.

The African elephant (Loxodonta africana) has the biggest ears of any mammal, but they are just 17 percent of the length of the animal's body, measuring nearly 4 feet (1.2 meters). (Photo courtesy of Siegfried Modola/Stringer/Getty Images.) 

The African elephant (Loxodonta africana) has the biggest ears of any mammal, but they are just 17 percent of the length of the animal's body, measuring nearly 4 feet (1.2 meters). (Photo credit: Getty Images/Nick Everett)

Caracal (Caracal caracal): According to the Smithsonian's National Zoo & Conservation Biology Institute, this small wildcat — found in Africa, Asia, and India — is known for its black tufted paws, which earned it the nickname desert lynx. (Photo courtesy of Getty Images/Martin Harvey) )

According to a study by the International Union for Conservation of Nature, the fennec fox (Vulpes zerda) is the smallest species in the canid family with the highest ear-to-body ratio. According to the Smithsonian's National Zoo & Conservation Biology Institute, the foxes are 14 to 16 inches (35 to 40 cm) long without the tail, and their ears are 4 to 6 inches (10 to 15 cm) long, making their ears 25 percent to 43 percent of their body weight. (Photo credit: Getty Images/Floridapfe from S.Korea Kim in cherl) 

According to National Geographic, some jackrabbit species that live in the western United States, Canada, and Mexico have ears that are up to 7 inches (18 cm) long, or one-third the length of their bodies. (Photo credit: Getty Images/Joe McDonald) 

Why do you have such large ears? Long-eared jerboas and other mammals that live in hot, dry environments benefit from large ears. African elephants, fennec foxes, and long-eared jerboas can thermoregulate by rapidly losing heat through their highly vascularized ears, according to Holden. The ears of these animals are wide and small, and they contain several tiny blood vessels, according to her. Blood circulates through the paws, releasing heat into the air and assisting the animal in cooling down.

Holden explained that when the animal is hot, the blood vessels in its ears expand to release even more heat. The animals' blood vessels constrict at night or when it's cold to help keep them alive.

According to Holden, "I think most people believe that big ears are usually associated with warmer environments." And, since African elephants live in a hotter environment than Asian elephants, African elephant ears are much bigger than Asian elephant ears. The ears of Asian elephants, which are about 1.6 feet (0.5 m) long, account for just about 8% of their total body length.

When it comes to heat dissipation, using one's ears to cool off is a good adaptation to desert life. According to Holden, it acts as a substitute for sweating, helping desert creatures to save water in an area where it is scarce.

The long-eared jerboa's large ears can also help it sense low-frequency noises from its insect prey and predators, according to Holden.