State- and Science-based Gray Wolf Reintroduction Act of 2020 This bill requires a state to obtain approval from the Department of the Interior before reintroducing the gray wolf ( Canis lupus ) and allows a person to take (e.g., kill or harm) a gray wolf under certain circumstances. Specifically, the bill prohibits a state from reintroducing the gray wolf unless Interior approves a state petition that meets the requirements of this bill. If an affected county makes a recommendation to deny the petition, then Interior may not approve the petition. A person in a state with an approved petition may take a gray wolf that is attacking a stock animal or dog if the person (1) is not trespassing or on land administered by the National Park Service; and (2) did not intentionally bait, feed, or otherwise attract the wolf.