frightened by a predator they often emit a high- pitched
alarm bark.
An acouchy is another type of rodent, represented by
two species in the genus Myoprocta. Acouchys look very
much like smaller versions of agoutis but have short,
yet obvious tails. Both species are found in northern
Amazonia and are ecologically similar to agoutis.
When agoutis retire for the evening, the Lowland
Paca (Cuniculus paca; plate 16- 25) comes out. There are
two paca species, one in the Neotropical lowlands that
ranges from tropical Mexico to northern Paraguay, the
other, the Mountain Paca (C. taczanowskii), is found
in higher elevation forests in northern South America,
from Peru to Venezuela. Pacas are common but are less
frequently seen than agoutis because of their nocturnal
habits. Pacas seem to prefer to be near water, and
daytime hours are typically spent resting in a burrow
along a stream bank. Monogamous, males and females
share a single territory but nonetheless forage alone and
occupy separate dens. Pacas resemble agoutis in shape
but have larger eyes and longitudinal white stripes
and spots along the sides of their reddish- brown coat.
Their bodies are larger and legs proportionally shorter
than those of agoutis, and pacas weigh more, up to
10 kg (22 lb). When threatened by a predator, a paca
will retreat to water and remain immersed until out of
danger (or air). Pacas, like agoutis, feed on fruit but
also take leaves and other plant materials, including
certain tubers. Unfortunately, paca meat is considered
to be highly tasty by humans, and pacas have been
overhunted in various regions.A more easily seen Neotropical rodent is the
enormous Capybara (Hydrochoeris hydrochaeris; plate
16- 26). It is discussed in chapter 12.
Seventeen species of New World porcupines and
dwarf porcupines (Erethizontidae; plate 16- 27) are
found in the Neotropics, and one species, the North
American Porcupine, is a well known resident in
northern and mountainous North American forests.
All porcupines bear stiff hairs that often form sharp
quills, but they differ from the familiar and related
North American species in that they have prehensile
tails. All porcupines have short faces with large,
bulbous noses and rather small eyes and ears. One of
the most wide- ranging and frequently encountered
species is the Brazilian Porcupine (Coendou prehensilis;
plate 16- 28), which ranges throughout Amazonia,
from extreme northern South America to southeastern
Brazil. Nocturnal and almost entirely arboreal (aided
by a strong prehensile tail), it climbs through the trees
like either a slow monkey or a fast sloth, depending
upon your frame of reference. Neotropical porcupines
feed on a combination of fruits (including those of
palms), bark, and leaves, though the diets of some
species are not well studied.
Spiny rats and tree rats (family Echimyidae) are
the most diverse group of caviomorph rodents,
with as many as 100 species ranging throughout the
Neotropics. Spiny rats (Proechimys spp.) are common
but are solitary and nocturnal and thus not often
observed unless one searches at night. The fur has
spines, particularly in the region of the lower back andPlate 16- 28. A rare sighting of a Brazilian Porcupine on the
ground, wandering across an open stretch of the Llanos
in Venezuela. Sometimes also called the Prehensile- tailed
Porcupine, it tends not to leave the safety of trees. Photo by
John Kricher.Plate 16- 27. The Mexican Hairy Dwarf Porcupine (Sphiggurus
[Coendou] mexicanus) is common throughout much of
southern Mexico and Central America. It is not found in South
America. Photo by James Adams.chapter 16 from monkeys to tarantulas: endless eccentricities 331