Adult females (does) usually weigh between 20 and 29 kg (44 and 64 lb) and have an average height of 66 cm (26 in) at the shoulders.

Adult females form loose matriarchal groups with one or two generations of offspring, while bucks feed and bed together only outside the breeding season.

[6] Key deer inhabit nearly all habitats within their range, including pine rocklands, hardwood hammocks, mangroves, and freshwater wetlands.

Key deer were hunted as a food supply by native tribes, passing sailors, and early settlers.

Hunting them was banned in 1939, but widespread poaching and habitat destruction caused the subspecies to plummet to near-extinction by the 1950s.

Still, recent human encroachment into the fragile habitat and the deer's relatively low rate of reproduction point to an uncertain future for the subspecies.

[11] The ongoing rise in sea level, owing to climate change, is a new threat to its remaining habitat on the islands of southern Florida.

Rapidly rising seas, a symptom of human-caused climate change, are challenging its continued existence and raising tough questions for the people trying to keep the nation's more than 1,300 other threatened and endangered species alive.

At the end of this period, however, most of the 1,000 acres (4.0 km2) of privately owned habitat land on Big Pine and No Name Keys will still be open for further development.

Thus, while the short term promises some cushion from extinction, the long-term prospects for the deer remain in doubt.

[citation needed] A portion of U.S. Route 1 was also elevated in 2003 to allow the deer to pass safely beneath the roadway, in an attempt to lessen the chance of road kills.

Also, hanging around people and developed areas in higher than normal densities makes them more susceptible to diseases, dog attacks, and entanglements in human trash, all of which can lead to increased injuries or death.