American alligators (Alligator mississippiensis) are ecosystem engineers, and are also considered a keystone species. An ecosystem engineer is an organism that creates, significantly modifies, maintains, or destroys a habitat. A keystone species is an organism on which other species in an ecosystem largely depend, and if the keystone species were removed, the ecosystem would change drastically. With Tropical Depression Fred heading our way, we thought it would be a perfect time to introduce you