Kentucky's bison herd has two tiny new members.Two bison calves were born at Big Bone Lick Historical Site earlier this month, state park officials said. The first was born on April 13, weighing between 40 and 60 pounds. The second was born April 17, standing within the first few minutes and running after a few hours.Bison typically have calves in April and May.Park officials warn that mother bison are extremely protective of calves and may hide them with crowds present.The park, located in Boone County, is known around the area for its free-roaming bison herd.Great bison herds once roamed this area and provided food, clothing and shelter for the American Indians and pioneers. Hunted to near extinction, the last of the wild bison were seen in Kentucky around 1800. The bison herd today recalls the park’s prehistoric past and are our only living mammalian link to the Ice Age.Big Bone Lick is equally known across the area for its unique name and scientific finds. The park's name derives from massive mammoth fossils found in the area from the Pleistocene megafauna. The mammoths are believed to have been drawn to the area by a salt lick deposited around the sulfur springs.