The “wolfy coyotes” of southeastern Texas hold genetic traces that may link them to red wolves, which were declared extinct in the wild in 1980. But a lack of data makes it challenging to define the species—or, for that matter, to determine whether a private company has cloned the red wolf or something else entirely. Upholt doesn’t deal in simple explanations; the pleasure, here, is in the complexity. The concept of a “species” is less sturdy than your high school biology teacher might have led you to believe. The most familiar definition is that a species consists of animals that can produce fertile offspring.