Answer:
They discovered many different mammals, reptiles, birds, and fish as a result of their expedition across what is today the Western United States.
Step-by-step explanation:
Lewis and Clark were the first to discover and carefully describe a number of species from the Great Plains including the white-tailed jackrabbit and the grizzly bear. Among the birds they discovered were Lewis' woodpecker, and greater sage-grouse. For reptiles, among new species or subspecies were the bull snake and horned lizard. And in terms of fish, blue catfish and mountain whitefish were newly discovered on their expedition west. There were also many plants that were discovered for the first time by Europeans on their expedition. Of course the indigenous peoples living there were already aware of all these creatures.