The dusky-footed woodrat (Neotoma fuscipes)
lives in the temperate region of western North America (Ingles 1961). Its
range excludes mountainous areas and areas of very high and very low rainfall.
This is a Mediterranean-type climate (Bailey 1996). Average rainfalls are
generally around 50-100 cm per year, but there is a lot of variation. Summers
tend to be hot and dry, while winters are cool and moist. The dusky-footed
woodrat probably encounters snow very rarely. The soil in its range has been
classified as mountain and desert soil, but a variety of soil types are present.
Fire is a natural part of this system.
The genus Neotoma consists of more than ten species of woodrats.
The dusky-footed woodrat is a medium-large woodrat of 230-400g (Carraway
and Verts 1991). Males tend to be slightly larger than females. All woodrats
belong to the family Muridae, the "Old World" mice and rats, even though
they are native to North America (Carraway and Verts 1991). The murids are
in the order Rodentia in the class Mammalia, phylum Chordata, kingdom Animalia.
Literature Cited
Bailey, R. G. 1996. Ecosystem Geography.
Springer, New York. 204 pp.
Carraway, L. N., and B. J. Verts. 1991. Neotoma
fuscipes. Mammalian Species No. 386:1-10.
Ingles, L. G. 1961. Mammals of California
and its Coastal Waters. Stanford University Press, p 232.
The Dusky-Footed Woodrat, Part 2
Dusky-footed woodrats (Neotoma fuscipes) can breed 1-3 times
a year and give birth to an average of 2.6 young per litter (Linsdale and
Tevis 1951). There are no good longevity data available, but N. floridana
can live over 3 years in the wild (Fitch and Rainey 1956). If we assume N.
fuscipes live an average of 2 years, half will die each year. If they
have 2 litters per year on average, and half are female, their intrinsic
rate of increase is about 2.1/individual/year (2.6 born - 0.5 dying). Young
are only allowed to nurse for about three weeks. They are a moderately r-selected
species.
The dusky-footed woodrat lives in large dens constructed of sticks
which protect it from its many predators. Therefore, the ability of predators
to limit population size may depend on den availability (Linsdale and Tevis
1956). Populations decrease during drought (Spevak 1983). Good acorn crops
lead to higher densities (Kelley 1989).
Literature Cited
Fitch, H. S. and Rainey, D. G. 1956. Ecological
observations on the woodrat, Neotoma floridana. Univ. of Kansas
Publications of the Museum of Natural History 8:499-533.
Kelley, P. A. 1989. Population ecology and
social organization of dusky-footed woodrats, Neotoma fuscipes. Ph.D.
Dissertation. Univ. of California, Berkeley.
Linsdale, J. M., and L. P. Tevis Jr. 1951.
The Dusky-footed wood rat. University of California Press, Los Angeles.
Linsdale, J. M., and L. P. Tevis Jr. 1956.
A five-year change in an assemblage of wood rat houses. Journal of Mammalogy
37:371-374.
Spevak, T. A. 1983. Population changes in
a Mediterranean scrub rodent assembly during drought. The Southwestern Naturalist
28:47-52.
The Dusky-Footed Woodrat, Part 3
Dusky-footed woodrats live in areas with dense vegetation, which provides
both food and protection from predators. They eat oak (both leaves and acorns),
poison oak, sage, and grasses (Meserve 1974). They will eat insects and other
foods opportunistically. They store food in their dens. Their major predators
are foxes, coyotes, bobcats, long-tailed weasels, mountain lions, spotted
owls, barn owls, great-horned owls, red-tailed hawks, rattlesnakes, and feral
dogs and cats (Carraway and Verts 1991).
A variety
of insects, spiders, reptiles, shrews, small rodents, and amphibians may
live in woodrat dens (Carraway and Verts 1991). Deer mice (Peromyscus
maniculatus) often live in woodrat dens (Cranford 1982). The mice may
occasionally steal food from but can not eat some of the toxic foods that
woodrats eat. Desert woodrats (N. lepida) are a competitor for oak
and dens. They are smaller than the dusky footed woodrats, which can dominate
them behaviorally (Cameron 1971). A variety of parasites live on and in N.
fuscipes, including fleas, trematodes, nematodes, protozoa, mites, and
botflies (Carraway and Verts 1991). Woodrats can suffer from plague and some
carry hantavirus. Mutualistic intestinal protozoa may help woodrats eat toxic
plants.
Literature Cited
Carraway, L. N., and B. J. Verts. 1991. Neotoma
fuscipes. Mammalian Species No. 386:1-10.
Cameron, G. N. 1971. Niche overlap and competition
in woodrats. Journal of Mammalogy 52:288-296.
Cranford, J. A. 1982. The effect of woodrat
houses on population density of Peromyscus. Journal of Mammalogy 63:663-666.
Meserve, P. L. 1974. Ecological relationships
of two sympatric woodrats in a California coastal sage scrub community. Journal
of Mammalogy 55:442-447.
The Dusky-Footed Woodrat, Synthesis
The dusky footed woodrat
(Neotoma fuscipes) lives in Mediterranean-type environment, which
has hot, dry summers and mild, moist winters. Plants in this climate tend
to senesce in the summer or have waxy leaves that resist desiccation. Grasses,
sagebrush and oak trees are major components of North American Mediterranean
communities. Fires are common in this climate. Grasses are not generally
harmed by fire because fires usually burn off tissue that has already senesced,
returning nutrients to the soil and leaving roots and seeds intact. Grass
fires rarely produce enough sustained heat to cause damage to the oaks. Oaks,
sages, and poison oak produce secondary compounds that can be toxic to herbivores
and reduce digestibility of their tissues. This may offer some protection
from herbivory.
All woodrats species are very good at dealing with plant chemicals
that harm other animals. The dusky footed woodrat has metabolic adaptations
that allow it to live on a diet of pure oak leaves. It can also eat poison
oak, sage and grasses (Meserve 1974). Mutualistic intestinal protozoa may
help woodrats digest toxic plants. There is little competition for this low-quality
food, so starvation will generally not limit dusky-footed woodrat populations.
This food may take a while to digest, so there is not unlimited energy available
to the woodrat. Years of good acorn crops increase woodrat density (Kelley
1989). This may be because acorns are rich in nutrients, so a woodrat can
get more energy in a day of feeding on acorns than in a day of eating oak
leaves. Populations decrease during drought (Spevak 1983). This could be
the result of lack of water itself, rather than a lack of food. Woodrats
store food in their dens, so they are probably not affected by temporary
food shortages. They get their water from living plants.
The major
predators of woodrats are foxes, coyotes, bobcats, long-tailed weasels, mountain
lions, spotted owls, barn owls, great-horned owls, red-tailed hawks, rattlesnakes,
and feral dogs and cats (Carraway and Verts 1991). Woodrats live in large
dens that are constructed of sticks and are often located in patches of poison
oak and thorny plants. Only one woodrat lives in each den, but the dens are
often the product of several decades of work by successive inhabitants. While
it is trying to build a new den a woodrat is vulnerable. Therefore, predation
may limit population size, but its effect may depend on den availability
(Linsdale and Tevis 1956). Woodrat seem to select areas with over 90% canopy
cover (Vogl 1967). This could protect them from large predators.
Woodrat
dens provide a cool moist microhabitat. Animals such as invertebrates, reptiles,
small mammals, and amphibians seem to take advantage of this (Carraway and
Verts 1991). Fungi and plants may also grow there. Deer mice (Peromyscus
maniculatus) often live in woodrat dens (Cranford 1982). The mice may
occasionally steal food but can’t eat the toxic species.
Desert
woodrats (N. lepida) compete with dusky-footed woodrats for oak products
and dens. They are smaller, so N. fuscipes can dominate them behaviorally
(Cameron 1971). Woodrats are territorial and will steal food from their neighbors’
unoccupied dens (Post and Reichman 1991).
A variety
of parasites live on and in N. fuscipes, including fleas, mites, botflies,
trematodes, nematodes, and protozoa. Woodrats can suffer from plague, and
some carry hantavirus. Epizootics do not seem to cause die-offs in woodrat
populations, perhaps because the animals are so solitary. Some fires do not
disturb woodrats (Tevis 1956), while others cause heavy fatalities (Chew
et al. 1959). Recolonization of badly-burned areas may be slow because of
a lack of existing dens and building materials.
Dusky-footed
woodrats can breed 1-3 times a year (Linsdale and Tevis 1951). Females give
birth to an average of about 2.6 young per litter. Young are only allowed
to nurse for about three weeks. Woodrats are a moderately r-selected species.
Like all mammals, they get maternal care. They do not get prolonged provisioning,
but a mother may tolerate her young living nearby. There is no paternal care.
In years when water and acorn conditions are good, populations can expand.
In poor years, individuals can supplement their diets with stored food, but
may not be able to reproduce. Carrying capacity is greatly affected by the
presence of oaks. Woodrat densities may be only 7/ha in chaparral habitats,
but get as high as 37/ha if there are also oaks in the area (Vogl 1967).
Woodrats
are active mainly at night, when they venture out to collect food (Carraway
and Verts 1991). A nocturnal lifestyle allows them to avoid high daytime temperatures
and makes them more difficult to see. Their use of a central food storage
site means that animals must make several trips to a food source. Woodrats
can also climb and they may use trees to escape mammalian predators.
Dusky-footed
woodrats do not have many direct interactions with humans. They may be a nuisance
if they occupy garages and other buildings. As a prey item of the endangered
spotted owl, they may soon receive more public attention.
Literature Cited
Bailey, R. G. 1996. Ecosystem Geography.
Springer, New York. 204 pp.
Carraway, L. N., and B. J. Verts. 1991. Neotoma
fuscipes. Mammalian Species No. 386:1-10.
Cameron, G. N. 1971. Niche overlap and competition
in woodrats. Journal of Mammalogy 52:288-296.
Chew, R. M., B. B. Butterworth, and R. Grechman.
1959. The effects of fire on the small mammal populations of chaparral. Journal
of Mammalogy 40:253.
Cranford, J. A. 1982. The effect of woodrat
houses on population density of Peromyscus. Journal of Mammalogy 63:663-666.
Ingles, L. G. 1961. Mammals of California
and its Coastal Waters. Stanford University Press, p 232.
Kelley, P. A. 1989. Population ecology and
social organization of dusky-footed woodrats, Neotoma fuscipes. Ph.D.
Dissertation. Univ. of California, Berkeley.
Linsdale, J. M., and L. P. Tevis Jr. 1951.
The Dusky-footed wood rat. University of California Press, Los Angeles.
Linsdale, J. M., and L. P. Tevis Jr. 1956.
A five-year change in an assemblage of wood rat houses. Journal of Mammalogy
37:371-374.
Meserve, P. L. 1974. Ecological relationships
of two sympatric woodrats in a California coastal sage scrub community. Journal
of Mammalogy 55:442-447.
Post, D. M., and O. J. Reichman. 1991. Effects
of food perishability, distance, and competitors on caching behavior by eastern
woodrats. Journal of Mammalogy 72:513-517.
Spevak, T. A. 1983. Population changes in
a Mediterranean scrub rodent assembly during drought. The Southwestern Naturalist
28:47-52.
Vogl, R. J. 1967. Wood rat densities in southern
California manzanita chaparral. The Southwestern Naturalist 12:176-179.