American bison have a bulky body covered in long dark brown fur throughout the winter and lighter weight brown coats in the summer. Some animals have been found with cream, grey or speckled coats.
Both males and females have small curved horns. These can measure up to 61cm (2ft). Behind the head of the bison is a large hump. A small beard is present on the chin.
Males are larger than females. At the shoulder, they average 195cm (6.5ft) tall. From the head to the end of the body they measure 2-3.5m (6.6-11.5ft). Their weight ranges from 320 to 1,000kg (700-2,200lbs).
American bison are herbivores. They graze on foliage such as grasses, lichens, woody plant leaves, flowering plants, mosses and sedges. Through winter they will access grasses buried in the snow by sweeping their head from side to side.
Each day the American bison needs to drink water. They can also fulfill this requirement by eating snow.
The United States of America and Canada are the homes of the American bison. Formerly their range extended from Mexico across the United States and in to Canada. Now they occupy just 1% of their former range. Most populations live in protected reserves.
Wild 15 years
Captive 25 years
They occupy the prairies, meadows and woodlands. Their former range also used to include forests and semi-deserts.
Mating takes place from August to September. Male bison engaging in head butting displays to win mating rights with the females. Meanwhile females will gallop about to encourage the contest.
Gestation last for between 270 and 285 days. At the end of this period a single calf (or in rare cases twins) is born. Newborn calves are a reddish-brown colour. It lacks the distinctive hump of the adults which will take a few months to start developing.
Just a few hours after it is born the calf is on its feet running around. Mothers are protective of their calves and will charge those who get too close. Males do not participate in raising the calf. It will take seven to twelve months for the calf to wean from its mother.
Sexual maturity is reached between 2 and 3 years old. It is unlikely males will breed till they are 5 years old due to competition from other males.
American bison form herds. Females and their young will form herds which may also consist of some adult males. These can number up to 60. Males can roam individually or in herds which may number up to 30.
When moving together American bison will form single file lines in which they travel. They can run at speeds of up to 50km/h (30mph) and are also adept swimmers capable of crossing rivers.
Activity can take place at any time of the day. Feeding takes place at dawn and dusk.
Grooming takes place regularly with the bison finding a tree upon which to rub themselves. They will also take dust baths in loose soil.
Predators of the American bison are few and far between. Adults are relatively safe from predation. Ill and young bison may fall prey to a mountain lion, wolf or bears.
Their biggest threat is humans, who during the 19th century almost drove them to extinction. Large scale hunts were carried out including from trains to kill as many bison as possible. Some were used to make coats while others were just left to rot. The process was supported by the US government who saw the extermination of the bison as a means by which to drive the native Americans on to reservations. By the late 19th century Bison numbers dropped as low as 100.
The American bison is the United States national mammal. It is also the state mammal of Kansas, Wyoming and Oklahoma. In Canada Manitoba uses the American bison as the official province animal.
It features on a range of US currency with the most well-known being the “buffalo nickel” which was circulated between 1913 and 1938.
It is commonly referred to as the buffalo but is not related to the buffalo of Africa and Asia.
They are regularly farmed for meat and wool in the United States and overseas.
American bison are the heaviest land animals in America.
Aune, K., Jørgensen, D. & Gates, C. 2017. Bison bison (errata version published in 2018). The IUCN Red List of Threatened Species 2017: e.T2815A123789863. https://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T2815A45156541.en. Downloaded on 28 April 2020.
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