Lewis and Clark encountered several animals on their historic voyage including grizzly bears, whose mighty strength the Indians had warned about; bison, with the explorers seeing a huge herd of over 20,000 that they called the American Bison; and coyotes, which they observed at night and sometimes during the day, making them the first to discover habits of the coyote. They also saw moose, which they identified scientifically, and white-tailed deer, finding tracks in the mud and killing one for food.