Lots of people don’t even know that when you see a raccoon or a rat snake in the lower Florida Keys, you are witnessing a rare, unique subspecies.
You see, an interesting thing happens when a species of animal finds itself in a balmy, subtropical ecosystem with very little fresh water. Many animals which occur in the lower islands of the Florida Keys, furthest away from the mainland, differ in appearance from their North American counterparts, and several are offically designated “subspecies” which occur no where else in the world. Apparently, scarcity of fresh water tends to make critters smaller, while year-long warmth and sunshine leads to lighter coloration.
Our most famous example of this miniaturization is the Key deer (Odocoileus virginianus clavium.) Key deer are a subspecies of the Virginia white-tailed deer which inhabit a cluster of tiny islands around Big Pine and No Name Key. Key deer are much smaller than their mainland counterparts, and they have developed the unique ability to drink small amounts of salt water. Only about 800 exist in the world.
The rosy red rat snake (Elaphe Guttata Rosacea) is the lower Keys version of the cornsnake. It is smaller and slimmer than its mainland counterpart, and has unique red/pink coloration with very little black.
The lower Keys are home to TWO unique subspecies of raccoon which have likely interbred prolifically and with the subspecies occurring in the upper Keys. Our Keys raccoons are smaller, leaner, and lighter than mainland raccoons. The Key Vaca raccoon (Procyon lotor auspicatus)originated in the Middle Keys, while the Torch Key raccoon (Procyon lotor incautus) inhabits the islands from Big Pine to Key West.
Dr. Roger Wood has extensively studied (Malaclemys terrapin rhizophorarum) a subspecies of the Diamondback terrapin. Mangrove terrapin inhabit the Key West Wildlife Refuge. According to Dr. Wood, Mangrove terrapin have the ability to tolerate water with extremely high salinity–though they are not marine turtles. And unlike their northern counterparts which hibernate in winter, mangrove terrapin sleep away the hottest summer months and are active during cooler winter temperatures.
Other unique subspecies within the lower Keys include the critically endangered Lower Keys marsh rabbit (Sylvilagus palustris hefneri,) the Florida Keys mole skink (Eumeces egregius egregius,) and the Lower Keys striped mud turtle (Kinosternon baurii baurii.) Even our rats are a subspecies of roof rat, alternately called palm rats or fruit rats (Rattus rattus frugivorous) depending on who you ask.