An enormous, lion-sized otter's fossilized bones that coexisted with early humans have been discovered in Ethiopia, according to a recent study.

The species, Enhydriodon omoensis, coexisted with a group of extinct human ancestors known as the australopithecines, bipedal hominids who lived from 4.2 million to roughly 2 million years ago, between the ages of 3.5 and 2.5 million. In comparison to its adorable modern relatives, E. omoensis was enormous; the study's authors calculated its weight to be around 440 pounds (200 kilograms).

The researchers believe that E. omoensis spent more time on land than in the water, even though it may have consumed both terrestrial and aquatic species through scavenging and hunting.

According to study co-author and geochemist Kevin Uno of Columbia University's Columbia Climate School in New York, "the peculiar thing, in addition to its massive size, is that [isotopes] in its teeth suggest it was not aquatic, like all modern otters." "We discovered that it differed from contemporary otters in that it consumed terrestrial animals."

The Lower Omo Valley in southwest Ethiopia, where it was discovered, inspired researchers to name the new species E. omoensis after it. Based on the remains of its teeth and femur, they calculated its weight. In order to determine how dependent a species was on water, the researchers also examined the ratios of stable oxygen and carbon isotopes in tooth enamel. Isotopes are variations of an element with different numbers of neutrons.

According to study co-author and geochemist Kevin Uno of Columbia University's Columbia Climate School in New York, "the peculiar thing, in addition to its massive size, is that [isotopes] in its teeth suggest it was not aquatic, like all modern otters." "We discovered that it differed from contemporary otters in that it consumed terrestrial animals."

The Lower Omo Valley in southwest Ethiopia, where it was discovered, inspired researchers to name the new species E. omoensis after it. Based on the remains of its teeth and femur, they calculated its weight. In order to determine how dependent a species was on water, the researchers also examined the ratios of stable oxygen and carbon isotopes in tooth enamel. Isotopes are variations of an element with different numbers of neutrons.

The latest study compares the size of these enormous otters to that of lions (Panthera leo), which may grow to a maximum length of 10 feet (3 meters) and weigh between 330 and 550 pounds (150 and 250 kg). According to the National Wildlife Federation, modern-day otters in North American rivers typically measure up to 4 feet (1.2 m) long and weigh no more than 30 pounds (14 kg), which makes them dwarfed by the enormous, extinct otters of Ethiopia.

The largest current otter species are the giant otters of South America (Pteronura brasiliensis) and the northern sea otters (Enhydra lutris kenyoni), which are found in the coastal seas of southern Alaska, British Columbia, and Washington. According to Zoo Atlanta, giant otters are larger and can reach lengths of up to 6 feet (1.8 m) and 70 pounds (32 kg). According to the Alaska Department of Fish and Game, northern sea otters can grow up to 5 feet (1.5 m) in length but can weigh more than 100 pounds (45 kg)—more than their South American cousins.