The scientific name of the pronghorn is "Antilocapra americana". Although first seen and described by Spanish explorers in the 16th century, the species was not formally recorded or scrutinized until the expedition in 1804-06 by Captain Meriwether Lewis and Second Lieutenant William Clark. Following the discovery of a few subspecies of the sharp-tailed grouse, Lewis and Clark came across the pronghorn near the mouth of the Niobrara River, in present-day Nebraska. Clark was the first European to kill a pronghorn, and described his experience as follows: