What kills the key deer?

Road kills from drivers on U.S. 1, which traverses the deer's small range, are a major threat, averaging between 30 and 40 kills per year, 70% of the annual mortality.

However, the population has made an encouraging rise since 1955, when population estimates ranged as low as 25, and appears to have stabilized in recent years. Still, recent human encroachment into the fragile habitat and the deer's relatively low rate of reproduction point to an uncertain future for the species.