European green toads will change their colour in response to heat and light changes, but to a greater degree than others. Female toads are larger than males and can lay 9,000 to 15,000 eggs at a time. They can reach a maximum size of 6 inches, but growth to this size is rare.

     European bison were hunted to extinction in the wild in the early 20th century, with the last wild animals of the B. b. bonasus subspecies being shot in the Białowieża Forest (on the Poland-Belarus border) in 1921, and the last of B. b. caucasus in the northwestern Caucasus in 1927.[2] B. b. hungarorum was hunted to extinction in the mid-1800s. The Białowieża or lowland European bison was kept alive in captivity, and has since been reintroduced into several countries in Europe. They are now forest-dwelling. The species has had few recent predators besides humans, with only scattered reports from the 19th century of wolf and bear predation. European bison were first scientifically described by Carl Linnaeus in 1758. Some later descriptions treat the European bison as conspecific with the American bison. It is not to be confused with the aurochs, the extinct ancestor of domestic cattle.

      In 1996, the International Union for Conservation of Nature classified the European bison as an endangered species. Its status has since been changed to being a vulnerable species. In the past, especially during the Middle Ages, it was commonly killed for its hide, and to produce drinking horns.