The biggest lion to ever exist? American and modern lions

None of the park service, zoo, conservation or research sources behind this article names the biggest lion of all time. The U.S. National Park Service describes the American lion as the largest extinct cat that lived in North America during the Pleistocene.

In Latin, the Park Service also says, the scientific name Panthera atrox means fearsome panther. Recent genetic work on some fossil remains of the American lion, on other extinct pantherine cats and on living large cats suggests the American lion is a distinct species, closely related to the extinct Eurasian cave lion, the service says. Smilodon, sometimes called a saber-toothed tiger, is not directly related to tigers, lions, leopards, jaguars or other pantherine cats, according to the service.

Where and when American lions lived

The Park Service says American lions have been found as far north as southern Alaska and as far south as southern Mexico, with finds reaching Maryland in the east and California in the west. It puts the oldest evidence of the American lion at about 340,000 years ago.

Isotopic analysis of American lion bones suggests a varied diet that included deer, horses, camels, tapirs, bison and mammoths, the service says. Fossil evidence suggests American lions may have lived in small groups, or may have had a degree of social structure similar to that of African lions today.

Build and body weight

The San Diego Zoo Wildlife Alliance’s fact sheet on the extinct American lion says the bending strength of Panthera atrox forelimbs was much greater than in a modern lion and similar to that of a brown bear. It also says males were consistently larger than females.

Body weight is harder to gauge, the fact sheet says, since fat leaves no impression on the skeleton. Whether extinct lions had manes is not known with certainty, the fact sheet adds, and in modern lions the mane is an important sexual signal.

What today’s lions weigh

The San Diego Zoo Wildlife Alliance’s fact sheet on African and Asian lions gives 150 to 225 kg (331 to 496 lbs) as male body weight and 122 to 192 kg (269 to 423 lbs) as female body weight. Lifespan is a separate question: see how long lions live.