Bison

Although there were once millions of bison roaming the North American grasslands, wholesale slaughter by the early European settlers brought them almost to extinction by the beginning of the twentieth century. Since then, due largely to the efforts of the American Bison Society, herds have steadily been built up in reserves, where they live in a semiwild state, and it is estimated that there are now some 20,000 animals. 

The male may be as much as 2.9 m (9 1/2 ft) at the shoulders, which are humped and covered with the shaggy, brownish-black fur that also grows thickly on the head, neck and forelegs.  The female looks similar to the male but is smaller; young are more reddish-brown. Both sexes have short, sharp horns. Primarily grazers, bison live in herds that vary from a family group to several thousand; huge numbers formerly made seasonal migrations in search of better pasture. They feed morning and evening. During the day, they rest, chewing the cud or wallowing in mud or dust to rid themselves of parasites. During the mating season, bulls (males) fight for cows (females), which give birth to a single calf, away from the herd, after a gestation of 9 months. Within an hour or two, mother and calf rejoin the herd. The calf is suckled for about a year and remains with its mother until it reaches sexual maturity at about 3 years old.