Mammals
Among the endangered mammals resident in the Florida Keys are the iconic manatees. Some of the largest whales in the world also visit, including the sperm, blue, and fins whales, all of which are endangered. Smaller endangered mammals include the Key Largo cotton mouse, the Key Largo wood rat and the Lower Keys marsh rabbit. The main threat to these smaller animals, and the primary reason they are endangered, is habitat destruction. The urbanization of the Florida Keys has not been good for endemic wildlife. Introduced animals, notably cats, are another serious threat.
Birds
The Florida Keys are an important feeding and breeding ground for hundreds of species of water birds, including endangered or threatened species such as the wood stork and the rosette tern. It is also the home for a variety of endangered raptors such as the Southeastern American kestrel and Arctic peregrine falcon and smaller birds including the endangered Bachman's warbler.
Fish
Wetland habitat also has endangered fish. In the Florida Keys these include the Key silverside and the Key blenny, both of which are found nowhere else. The threats to fish are similar to the threats to other animals, with habitat destruction being possibly the biggest threat. Fish are also highly sensitive to water pollution.
Reptiles
Five of the seven species of sea turtle inhabit the Florida Keys, including the critically endangered hawksbill, Kemp's Ridley and leatherback turtles. Other endangered reptiles include numerous species of lizard and snake such as the Key mole skink and the Eastern indigo snake, the American alligator and the Key mud turtle.
Invertebrates
Less obvious than the large vertebrates, invertebrates are an essential part of every ecosystem and vulnerable to much the same threats. Species known to be endangered in this habitat include mollusks such as the Stock Island tree snail, insects such as Schuas' swallowtail butterfly and aquatic organisms such as corals.