Description
The Key Largo woodrat is similar to Neotoma floridana floridana and cannot be distinguished from it in size or external anatomy. It differs in the shape of the sphenopalatine vacuities (openings in the roof of the mesopterygoid fossa, the gap behind the palate), which are narrower and shorter than inN. f. floridana. On average, males are a bit larger than females. In the holotype, an adult male, total length is 368 mm (14.5 in), tail length 167 mm (6.6 in), hindfoot length 37 mm (1.5 in), ear length 26 mm (1.0 in), dimensions of the testis 14 × 8.5 mm (0.55 × 0.33 in), and mass is 207 g (7.3 oz).[9]
Distribution and habitat
The animal is found exclusively in the northern part of Key Largo, at least 210 km removed from its nearest kin, the Florida woodrat. It is endemic to the tropical hardwood hammocks of Key Largo, where its habitat has shrunk by half since the 1920s, and the remainder is fragmented, thinned, and developed. It retains some 850 ha, most of which is in the Dagny Johnson Key Largo Hammock Botanical State Park and the adjacent Crocodile Lake National Wildlife Refuge.[5]
Behavior
Shelter
The Key Largo woodrat builds nests out of sticks; these nests can be as high as a man's shoulder. They are handed down from generation to generation, and some are possibly centuries old.[10]
Conservation
Since the Key Largo woodrat has a small and specific habitat, it is susceptible to human encroachment. Since the 1920s, it has lost almost half of its traditional habitat.[5] In the early 1980s, biologists began equipping rats with radio devices to count them and study them;[11] by the end of the 1980s, a study showed that the rat had disappeared from Key Largo proper and its total population had dwindled to some 6500 animals on North Key Largo.[2] Its fate in Key Largo was tied to that of the American Crocodile, and when a planned reservation for the crocodile in North Key Largo bogged down during the presidential transition in the US Administration in 1980, the woodrat was threatened with extinction; the crocodile reservation was to be a haven for the woodrat, and also for the rare Schaus Swallowtail butterfly. A project called Port Bougainville, with 15 hotels besides condos, would add 45,000 inhabitants to North Key Largo by the year 2000, adding to the pressure on the crocodile and other animals.[12]
The 406-acre (1.64 km2) project, which by 1982 included a planned 2806 units, ran into opposition from environmental groups and by 1984 had ground to a halt after one of the investors withdrew a $54 million investment.[13] in 1983 already, the administration had intervened and declared the Key Largo woodrat and the Key Largo cotton mouse endangered on a "temporary emergency basis";[14] the developer of a golf course, for instance, was ordered to restore the area he was illegally developing, to preserve the woodrat's habitat.[15] Since 1984, the Key Largo woodrat is on the United States list of endangered species, along with the Schaus Swallowtail and the Key Largo Cotton Mouse.[16]
By the 1990s, the animal's habitat had shrunk to about three square miles,[17] and the Key Largo woodrat was called "one of the rarest creatures on earth."[18] The animal also suffers from competition with the infamous Rattus rattus.[19]
As of 2005, the Key Largo woodrat population was still struggling to survive among the half-built condominiums of the former Port Bougainville project,[20] which in 2003 became part of the Dagny Johnson Key Largo Hammock Botanical State Park.[21] 400 acres (1.6 km2) of the developer's land were bought up by the Federal Deposit Insurance Corporation in 1987;[22] the Botanical State Park now takes up 2,421 acres (9.80 km2).[21] Besides in this area,[23] the rat finds refuge in the Crocodile Lake National Wildlife Refuge, which has a captive breeding program currently in operation but increasing development continues to threaten the animal.[24] Supplemental feeding has produced mixed results: they seem to delay the extinction of the species, but when feedings are stopped the "negative population trajectories accelerated."[25]