Question: What species of deer lives in the Florida Keys and is an example of Foster's rule?
Context: The Key deer ("Odocoileus virginianus clavium") is an endangered deer that lives only in the Florida Keys.  It is a subspecies of the white-tailed deer ("O. virginianus").  It is the smallest North American deer. The Mule Keys are a group of scattered islets in the Florida Keys in Monroe County, Florida, United States.  They are between 3 and 12 miles (5–20 km) west of Key West, separated from it by the Northwest Channel.  On the west, they are separated from the Marquesas Keys by the 6-mile (10 km) wide Boca Grande Channel.  They belong to the outlying islands of the Florida Keys.  Administratively, they are an unincorporated area of Monroe County.  The islets are part of the Key West National Wildlife Refuge.  The area of the islets totals 1.07 mi² (2.77 km²), of which 1.02 mi² (2.63 km²) are land area and 0.05 mi² (0.14 km²) inland water bodies (on three of the keys).  The islets are uninhabited except for Mule Key, for which the census of 2000 lists one housing unit with a population of two (park rangers or coast guard). The Miami Rock Ridge is a continuous limestone outcropping which formerly encompassed a large extent of far southern Florida, including portions of the Everglades ecosystem.  The traditional base of the elevation ranges from northern Dade County (the approximate latitude of North Miami Beach) southward to the upper Florida Keys, and it extends southwest into Everglades National Park and Long Pine Key.  The coastal ridge was traditionally a component of the endangered pine rocklands, which grew upon the length of the ridge.  The environmental community consisted of a large and continuous expanse of South Florida Slash Pines "(Pinus elliottii var.  densa)", which was interspersed by tropical hardwood hammocks.  The globally imperiled pine rockland community, which also encompassed the Florida Keys and The Bahamas, supported numerous endemic plant species; 20 percent occur nowhere else in the world.  The communities of the Miami Rock Ridge are maintained by wildfires, including natural fires caused by lightning strikes; this affects the vegetation and its associated inhabitants, thus maintaining a diverse ecosystem.  The substrate—often consisting of marl—and climate also affects the height of vegetation; thus a mature subtropical hammock typically does not exceed 59 ft on the Miami Rock Ridge.  Today the original communities have been largely removed by development, and the remaining pieces of the ecosystems are scattered into tiny fragments in extreme southeast Florida; they now encompass small fractions of their original range.  Simpson Park Hammock and Alice Wainwright Park contain small fragments of tropical hardwood hammock. Florida Keys Council of the Arts is a leading cultural organization in the Florida Keys, and serves the population from Key Largo to Key West.  A non-profit local arts agency, it makes grants, operates the Monroe County Art in Public Places program, sponsors seminars, and manages the on-line cultural calendar for the region .  It also manages the County's Cultural Umbrella grants process, under the Tourism Development Council and serves as a leading advocate for cultural tourism on lower Florida.  In 1998, the Florida Keys Council of the Arts was designated by the Board of Monroe County Commissioners as the area's Local Arts Agency as provided by Florida Statute 286.011. Foster's rule (also known as the island rule or the island effect) is an ecogeographical rule in evolutionary biology stating that members of a species get smaller or bigger depending on the resources available in the environment.  For example, it is known that pygmy mammoths evolved from normal mammoths on small islands. Similar evolutionary paths have been observed in elephants, hippopotamuses, boas, deer (for example Key deer) and humans. The Florida Reef (also known as the Great Florida Reef, Florida reefs, Florida Reef Tract and Florida Keys Reef Tract) is the only living coral barrier reef in the continental United States.  It is the third largest coral barrier reef system in the world (after the Great Barrier Reef and Belize Barrier Reef).  It lies a few miles seaward of the Florida Keys, is about 4 miles (6 to 7 km) wide and extends (along the 20 meter depth contour) 270 km from Fowey Rocks just east of Soldier Key to just south of the Marquesas Keys.  The barrier reef tract forms a great arc, concentric with the Florida Keys, with the northern end, in Biscayne National Park, oriented north-south and the western end, south of the Marquesas Keys, oriented east-west.  The rest of the reef outside Biscayne National Park lies within John Pennekamp Coral Reef State Park and the Florida Keys National Marine Sanctuary.  Isolated coral patch reefs occur northward from Biscayne National Park as far as Stuart, in Martin County.  Coral reefs are also found in Dry Tortugas National Park west of the Marquesas Keys.  There are more than 6,000 individual reefs in the system.  The reefs are 5,000 to 7,000 years old, having developed since sea levels rose following the Wisconsinan glaciation. Soldier Key is an island in Biscayne National Park in Miami-Dade County, Florida.  It is located between Biscayne Bay and the Atlantic Ocean, about three miles north of the Ragged Keys, five miles south of Cape Florida on Key Biscayne, seven-and-a-half miles east of the mainland and three miles west of Fowey Rocks.  It lies on the Safety Valve, a sand bar that separates Biscayne Bay from the Atlantic Ocean and moderates storm surges into the bay.  The island is small, about 200 yards (200 meters) by 100 yards (100 meters) with a maximum elevation of six feet (under two meters).  It is at the southern end of the along-shore movement of sand that feeds the barrier islands to the North (such as Key Biscayne) and is the northernmost exposure of the Key Largo limestone (fossilized coral reef) which forms the "true" Florida Keys.  The island is covered by grass and shrub vegetation typical of the Florida Keys.  Although the island was described as "thickly wooded" in 1894, as of 1955 the only wooded areas were mangroves on the fringes of the island.  Also as of 1955, there were several buildings on the island, and a boat slip protected by jetties. The Florida Keys Keynoter is a twice-weekly broadsheet format newspaper owned by The McClatchy Company and is a subsidiary of the Miami Herald.  It primarily serves Monroe county in the U.S. state of Florida.  In addition to publishing regular issues on Wednesday and Saturday, the Keynoter also publishes the quarterly magazine Unwind.  "The Keynoter" is a partner of the Upper Keys Reporter, which specializes in coverage of the Upper Florida Keys, including Key Largo. The Florida Keys National Marine Sanctuary is a U.S. National Marine Sanctuary in the Florida Keys.  It includes the Florida Reef, the only barrier coral reef in North America and the third-largest coral barrier reef in the world.  It also has extensive mangrove forest and seagrass fields.  The marine sanctuary includes a 2,800 square nautical mile (9,600 km²) area surrounding the Keys and reaching into the Atlantic Ocean, Florida Bay and the Gulf of Mexico.  The sanctuary was established in 1990. Key Largo is an island in the upper Florida Keys archipelago and is the largest section of the Keys, at 33 mi long.  It is one of the northernmost of the Florida Keys in Monroe County, and the northernmost of the Keys connected by U.S. Highway 1 (the Overseas Highway).  Its earlier Spanish name was "Cayo Largo", meaning long islet.
Answer: Key deer