European bison (often called wisent, from the German word for “bison”) are the largest land mammals in Europe but are slightly smaller than their close relative, the American bison.
The adult male European bison weighs in the range of 800 to 2,000 pounds (400 to 920 kilograms); the female weighs from 650 to 1,200 pounds (300 to 540 kilograms). A good-sized male has a shoulder height of about 6 to 6.5 feet (1.8 to 2 meters) and his body is about 9 feet (2.75 meters) long. The head is very big, and both males and females have horns.
European bison are varying shades of brown, and they have long hair growing from their necks and foreheads and a short beard on their chins. They have a shoulder hump and carry their heads high. In winter, they grow an extra coat of fur to protect themselves from the cold.
Unlike American bison, which live on the plains, European bison live in forests where they can browse (eat) on the tender shoots, twigs, and leaves of trees and bushes. They generally live close to moist clearings where they graze on grass, moss, herbs, and other greens.
During the spring, autumn, and summer, they spend most of their time browsing and grazing. In the primary home of bisons in the Bialowieza Forest, Poland, there is a centuries-old tradition of humans providing hay for the bison to eat in winter.
Thus it has become part of the seasonal habit of the species to gather in large groups in winter around the places where the humans have laid out food for them. Today, park wardens provide European bison with hay, oats, and sugar beets in the winter.
Female bison, with their calves and sexually immature young, live in herds of about 20 to 30 animals. Bulls (males) live alone most of the year. When the mating season begins in August each year, the bulls join up with the herds and fight each other for females.
Each mating bull may take up to about a dozen females to mate. When the mating season is over, the bulls go back to living alone. For the females, the gestation (pregnancy) period is about nine months.
During calving season, from May to July, the female leaves the herd. Female European bison generally bear one offspring in a season, and occasionally two. In winter, European bison gather into larger groups near their feeding stations. Their life span is about 25 years or longer.
Habitat and current distribution
Today the largest concentration of European bison live in Poland’s Bialowieza National Park, which is Europe’s last remaining primeval forest (one that has been there since ancient times). The park, which covers an area of about 20 square miles (52 square kilometers), lies within the 220-square-mile (570-square-kilometer) Bialowieza forest.
Early in the twentieth century, hunters killed off the last of the wild European bison, and since then, captured bison raised in zoos have been successfully reintroduced into their natural habitat, particulary in Bialowieza, where they can be protected.
In the past few decades, European bison have also been either reintroduced or introduced to the wild from captivity in other areas, including Russia, Belarus, Kyrgyzstan, Lithuania, and Ukraine. In 1999, there were an estimated 3,200 European bison in captivity and in the wild.
History and conservation measures
Since ancient times, European bison ranged through the deciduous forests (made up of trees that shed their leaves each season) extending from Britain across Europe into Russia. The Bialowieza Forest in what is now Poland was protected for royal hunting from the fifteenth to the eighteenth century; during those centuries the game in the forest was fed by humans.
In the nineteenth century, Russia took control of the forests. Overhunting caused a significant reduction in bison, as well as other animals. During World War I (1914–18), a tremendous number of bison were killed by hunters and soldiers, and in the early 1920s the last bison in the wild was killed by a poacher (illegal hunter).
In 1923, the 54 European bison living in zoos represented the entire population of the species. These were placed in breeding programs for several decades. In the 1950s, the animals bred in captivity were released into the wild in Bialowieza, which had been declared a national park in the 1930s. These animals have been carefully protected and have prospered.
There are approximately 3,200 animals in existence today, and they are all the descendants of 12 European bison from the breeding-in-captivity programs started in the 1920s. This is potentially a problem for the species in terms of introducing enough genetic diversity (variety of biological units that pass on inherited traits) within the herds in the wild.
The reintroduction of bison into the Bialowieza forests has been so successful that some carefully managed culling (eliminating some of the bison so that the habitat is preserved for the rest) is necessary.
There are now programs expanding the bison’s range into Belarus, Ukraine, Russia, and beyond. One of the biggest concerns for the preservation of the European bison is to foster genetic variation among thousands of animals with only twelve ancestors.