New York Status: Endangered
Federal Status: Not Listed
The Allegheny woodrat is the second largest member of the native North American rats and mice (subfamily Sigmodontinae), weighs up to a pound, and is roughly the size of a grey squirrel. Allegheny woodrats measure approximately 16 inches long, half of which is its tail. The majority of its body is brownish-grey in color, while the undersides and feet are white. Woodrats have large eyes, naked ears and long vibrissie (whiskers) which when pulled back will reach the shoulder. The most visible characteristic which sets the Allegheny woodrat apart from Old World rats is its tail. The tails of European rats are naked or slightly hairy with the skin clearly visible beneath. The tail of the Allegheny woodrat is completely covered with hairs approximately one-third of an inch long and is prominently bicolored; nearly black above and white below.
Allegheny woodrats have an agreeable disposition around people and are generally docile when handled. They've even been observed trying to remove buttons from a person's shirt and drag away the blanket of a sleeping camper! However, woodrats can be very fierce around their own kind. Many sport battle scars from unwelcome encounters and can be killed if escape is not possible.
Woodrats are generally nocturnal. They scurry about in sparsely vegetated areas of boulders and crevices, making use of bare travel ways and labyrinths to travel silently and securely throughout their domain. They are mainly vegetarians and feed on a wide variety of fruits, nuts, berries, and green plant material. They lay in stores of dried green vegetation under protective cover of ledges. Red oak acorns seem particularly desirable when they are available. In the course of normal activity woodrats rarely travel more than a few hundred feet from the center of their territory, although dispersing animals can travel miles before finding a new home. They regularly patrol the borders of their territories and are well aware of the activities of their neighbors. Compared to other rodents, woodrats are not prolific breeders averaging one to three offspring per litter. Under ideal conditions they can produce three litters annually in nests of finely shredded bark. The young are born after a gestation period of 30 to 37 days and are weaned within a month. Woodrats have been known to survive for nearly three years in the wild and considerably longer in captivity.
Distribution and Habitat
Quick retreat appears to be the preferred defensive strategy as they tend to build nests in well protected sites with multiple avenues of escape. In some instances researchers have found dried leaves placed around the nest on likely approach routes that appear to act as alarms to warn the residents of approaching danger. Like their western counterparts, which are often called pack rats, the Allegheny woodrat often collects environmental oddities to decorate their nest site. It is not unusual to find bits of bones, human rubbish, or even animal feces within and around the nest site.
The Allegheny woodrat has a long history in New York. Researchers have found woodrat bones over 20,000 years old as far north in the Hudson river valley as Albany. In historical times, records of woodrats have been restricted to accumulations of large talus boulders throughout the Hudson Highlands and Shawangunk mountains of southeastern New York, east to the Hudson River and south to the New Jersey border.
As recently as the mid 1960s the woodrat could be found wherever these large boulders accumulated in layers deep enough to form complex systems of passageways. By the mid 1970s naturalist Dan Smiley of Mohonk, New York was the first to notice that the Allegheny woodrat was in decline in the state. By 1980, biologists knew of only 5 extant sites, the last of which became extirpated in 1987.
Efforts to understand the cause of the decline began in 1990 when DEC biologists captured thirty woodrats that had been captured in West Virginia, fitted with radio collars, and released near Mohonk, New York at two formerly occupied sites. Within six months all of the animals at one site had perished; within a year the remaining animals were gone. Including offspring, biologists monitored 52 animals of which just twelve carcasses were recovered in good condition for examination. In 11 of 12 cases the animal had been killed by a parasite called raccoon roundworm (Balyisascaris procyonis). The eggs of the parasite are contained within raccoon feces and contaminate the soil when the feces decompose. Woodrats walking across raccoon droppings are probably infected when they groom or when they carry feces to their nest sites. Raccoons are often attracted to the same rocky sites as woodrats; therefore, an increase in raccoon numbers puts woodrats at great risk of infection. When coupled with the woodrat's "pack rat" behavior of collecting feces, the increase in raccoon numbers that we have experienced in recent decades has spelled doom for the woodrat in New York.
Management and Research Needs
For perhaps the first time in thousands of years the Allegheny woodrat no longer haunts the cliffs of southeastern New York. Their chance of returning appears bleak at this time as it would seem to require a substantial and long term decline in raccoon numbers.
Given the ability of raccoons to thrive near human development, the future of the Allegheny woodrat in New York is bleak. Research in areas where the animals still exist, or perhaps further experimental research in New York, might shed additional light on the woodrat's problems, but we currently do not see solutions on the horizon.