Key Deer Facts:
• Key Deer Basics: What’s a Key Deer and what makes them so special?
The Key Deer, Odocoileus virginianus clavium, is a subspecies of the ordinary ubiquitous Virginia Whitetail Deer, but the Key Deer has evolved and presently exists in the “wild” only on a few islands in the Florida Keys. It is by far the smallest of any deer in the Americas. Academic literature cites “adult males, or bucks, weigh only 55-75 pounds. Adult females, or does, weigh slightly less. On average, they stand only about 24 to 32 inches at the shoulder.” That’s about the size of a medium-sized German Shepherd. From personal experience, few of the large, old bucks tip the scales just past a hundred pounds, but they have been extremely lucky to have survived to reach that size (see the Key Deer Biology section for details).
The Key Deer are historical colonizers of the Florida Keys from days some 30,000-20,000 years ago when lowered sea levels had the whole Keys chain firmly attached to the Florida mainland: back then whitetails roamed up and down the Keys…before being cut off from the mainland by the last glaciation melt period around 10,000 years ago. The waters rose and deer got stuck on the Keys. Now what??
Typically, living things stuck on livable areas but with limited resources (food, water, shelter) tend to become smaller in size. It’s called the “Island Dwarfing Effect”. Unlike your Big Brother, you actually have better survival chances since you need less food, less drinking water, and can find smaller, easier shelter. Besides the Key Deer in the Florida Keys, this phenomenon has been documented worldwide: the pony-sized Island Mammoths that used to live on Wrangel Island near Siberia, dwarf Elephants that once lived on Crete, and dwarf Emus that once lived on islands around Australia. While there are still people circulating unfounded stories that white men just brought upper-states whitetails to the Islands to start or enrich the existing deer stock in the past 50-100 years, genetic studies prove them wrong: miniature Key deer have been in the Keys way longer than “paleface” has ever shown up in the Keys. (see Key Deer History and Biology sections for the science).
Historically, the Key Deer first likely roamed all of the Key island chain, from the Florida mainland down to existing “Key West”. What likely started their genetic separation from their historic counterparts on the mainland was…drinking water. Food was not, and even now, is not generally the main problem – Key Deer eat more than 150 species of plants. On the other hand, one can get a certain amount of water directly from the plants and another bit from metabolism. But then, you’re done! You just HAVE to get a drink of fresh water from somewhere to survive. Due to varying limestone formations of the Keys Island chain there were – and in a VERY FEW places still are – depressions that hold fresh water from seasonal rain storms. Most of them formed in the Lower keys, so that’s where Key Deer survived then. Much of that habitat has been obliterated by humans through the 1960s-to-present, however, so they don’t have much to hold on to today.
The problem is, rain comes seasonally to the Keys. So the “Fresh-water Holes” may be useful during the rainy months, but progressively start drying out during dry seasons. And to make it worse, hurricanes would throw salt water floods over the islands to render the inner-island fresh water holes essentially useless. The Key Deer adapted in that they can, on occasion, drink water with a higher salinity content than any living deer…and survive. Enough problems, right? NO!! Before the 1400s-and into the 1500s, local Indians hunted them for food. Then came white men and the hunting pressure increased, first to provide meat provisions for passing ships, then also for sport. Although habitat may have still been plentiful into the 1920s and 30s (despite some losses due to human colonization), the number of Key Deer plummeted. In 1930, famous syndicated cartoonist (and later founder of the National Wildlife Federation) Jay “Ding” Darling published a cartoon entitled “The Last of the “Toy” Deer of the Florida Keys”, showing a bunch of dog-accompanied men setting fire to coastal brush, chasing Key Deer into the water, and shooting them. The drawing is widely credited with starting a nationwide effort to preserve Key Deer from extinction.
(Courtesy of the Jay N. ‘Ding’ Darling Wildlife Society)
Although ideas to protect Key Deer and set aside habitat land for them circulated in Congress and the White House in the 1930s and 40s, and hunting of Key Deer was outlawed in 1939, poaching and habitat destruction continued unabated. The darkest times came around 1950 when only 50 Key Deer (or less) were alive in the world. The saving of Key Deer from total extinction is generally credited to one man: Jack Watson. In 1946 Mr. Watson became an officer for the U.S. Fish and Wildlife Service, and quickly became the Key Deer’s best friend – realizing not only how adorable but also how precariously close to extinction they are. He declared a one-man war on poachers and used whatever tactics were necessary. These included disabling their car with bullets to the engine or gas tank, or setting their boat on fire. He also spent much time educating the government and public about the Deer and, in 1957 when the National Key Deer Refuge was (finally!) established, he became its first manager. He finally retired from that position in 1974.
Although saved by a hair from extinction, the Deer were confronted with major habitat losses during the 1960s, 70s and 80s due to human expansion and construction. Their numbers rose gradually but the “Key Deer” was officially put on the Endangered Species list in 1967, and remains there today. The major reason is closely linked to its very limited habitat range. Existing population estimates hover around 800 in mid-2017, however, the vast majority are concentrated on Big Pine and No Name Keys – two islands located right next to each other encompassing less than 12 square miles total area. One criterion for an endangered species listing is that the species’ relatively small population exists in a small-enough geographical area that a single natural or human-caused cataclysmic event (or linked events) could cause full extinction.
With the Florida Keys having a long history of devastating hurricane hits, this concept is of special concern for the Key Deer (and several other endangered species living in the Keys). Indeed, while (fortunately) not cataclysmic, Hurricane Wilma in 2005 (which brought hurricane winds and the highest storm surge since 1965 over the Keys) caused significant deer mortality, first through drowning, then through lack of forage). Disease epidemics are another concern, the most recent example being the New World Screwworm infestation during 2016-17 (undeniably caused by humans). It caused 135 known deaths and an unknown number of deaths of deer that perished in the bush unfound, all within a few months.
The Key Deer thus continue to face serious threats to their survival, often linked to modern humans’ invasion of their habitat. Being ever-adaptive, as per several research studies, they have been changing their individual and social behavior to better co-exist with and within human communities that pepper their “last-stand” habitat range on Earth. But ultimately, the burden is on us to ensure that they survive.