Bison latifrons

Bison latifrons, also known as the giant bison or long-horned bison, is an extinct species of bison that lived in North America during the Late Pleistocene epoch ranging from southern Canada to Mexico. It is noted for large body size and its distinctive long horns.

Description
Because only skulls and horns of this species have been found well preserved, the size of B. latifrons is currently not clearly known. Based on leg bones, the mass of B. latifrons has been estimated to be 25-50 percent larger than that of modern B. bison, making it undoubtedly one of the largest-ever ruminants.

The known dimensions of the species are on average larger than any extinct and extant bovids, including both the American bison and the European bison, making it the largest known bovid. Overall, it was probably around 4.75 m in length and stood about 2.3 m or up to 2.5 m tall at the withers. With an estimated weight of 1250 kg to 2,000 kg, B. latifrons was one of the largest ruminants ever, rivaled in mass only by the modern giraffe and the prehistoric long-horned buffalo Pelorovis. Fossil measurements of B. priscus gigas indicate the species was potentially analogous to B. latifrons both in morphology and habitat selection, attaining similar body sizes and horns that were up to 210 cm apart.

The horns of B. latifrons measured as great as 213 cm from tip to tip, compared with 66 cm to 90 cm in modern Bison bison.

Evolution
Bison latifrons is thought to have evolved in North America from Bison priscus (sometimes called the steppe bison) another prehistoric species of bison that migrated across the Bering Land Bridge around 195–135,000 years ago, before dispersing southwards around 130,000 years ago. The earliest fossil Bison latifrons, as well as one of the oldest well dated bison specimens in central North America, is from the Snowmass site in Colorado, dating to the Last Interglacial (Sangamonian), around 120,000 years ago. It has been suggested that a population of B. latifrons gave rise to Bison antiquus, the ancestor of modern American bison before 60,000 years ago with the two species co-existing alongside each other.

Habitat and behavior
Bison latifrons ranged across much of North America, extending from southern Mexico to southern Canada, as far west as California and as far east as Florida and the American Midwest. Isotopic analysis from specimens found in Florida suggests a largely grazing based diet, while isotopic analysis of specimens from Clark Quarry, Georgia, suggest that these specimens had a mixed feeding diet (both browsing and grazing), with their diet varying according to the seasons.

Extinction
While many studies have suggested that the B. latifrons went extinct around or before 20,000 years ago, a 2022 study reported remains from South Texas dating to around 13,000 years Before Present. Human hunting pressure may have played a role in the extinction of B. latifrons.