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.^[2] It is noted for its large body size and its distinctive long horns.^[3]

Bison latifrons Temporal range: Late Pleistocene PreꞒ Ꞓ O S D C P T J K Pg N ↓
Bison latifrons skeleton
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Family:	Bovidae
Subfamily:	Bovinae
Genus:	Bison
Species:	†B. latifrons
Binomial name
†Bison latifrons Harlan, 1825[1]

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.^[4][5]

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 (15.6 ft) in length and stood about 2.3 m (7.5 ft) or up to 2.5 m (8.2 ft)^[6] tall at the withers.^[7] With an estimated weight of 1,250 kg (2,760 lb),^[8][9] or possibly over 2,000 kilograms (4,400 lb) in very large males,^[3] B. latifrons was one of the largest ruminants ever, rivaled in mass only by the modern giraffe and the prehistoric long-horned buffalo Syncerus antiquus.^[10] The horns of B. latifrons measured as great as 213 centimeters (84 in) from tip to tip, compared with 66 cm (26 in) to 90 cm (35 in) in modern Bison bison.^[11][12]

Evolution

Skull at the Royal Tyrell Museum in Drumheller, Alberta, Canada

The ultimate ancestor of all American bison species, the steppe bison (Bison priscus), first entered northwest North America (Eastern Beringia, comprising Alaska and Yukon) around 195,000–135,000 years ago during the Penultimate Glacial Period (Illinoian), and then entered central North America at the beginning of the Last Interglacial (Sangamonian) around 130,000 years ago, following the melting of the Laurentide Ice Sheet, with a B. priscus population subsequently evolving into Bison latifrons. 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 around 120,000 years ago.^[3][13] 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.^[13]

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.^[2] Though it was primarily a grazer, B. latifrons exhibited a high degree of dietary flexibility and adaptability across its range.^[14] Isotopic analysis from specimens found in Florida suggests a largely grazing based diet,^[15] 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.^[16]

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.^[17] Pressure from human hunting may have played a role in the extinction of B. latifrons.^[18]