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New World porcupines
Erethizontids are medium-sized to large animals with head and body
length from 450 mm ( Echinoprocta) to 860 mm ( Erethizon). Animals
of the genus Erethizon weigh up to 18 kg. There is considerable
diversity among the four genera of erethizontids with respect to
body form. Coendou and Sphiggurus are arboreal animals,with long,
spineless, prehensile tails and wide foot pads. Erethizon and
Echinoprocta are less arboreal than the other two genera and have
short tails (although Erethizon is an excellent climber and may
spend a considerable portion of its life in the trees). All have
four digits on the forefeet. On the hindfeet, the hallux is reduced
in most, but it is relatively large and clawed in Erethizon.
All erethizontids share certain characteristics, such as hairs
modified into spines with overlapping barbs; a dental formula 1/1,
0/0, 1/1, 3/3 = 20; flat, rooted, hypsodont cheekteeth with wide
reentrant folds (3 labial and 1 lingual on the upper molars, but the
anterior and posterior folds soon appear as islands as a result of
toothwear). They are hystricognathous and hystricomorphous. Their
zygomatic arches are strongly built but the jugal does not contact
the lacrimal. The infraorbital canal is huge, and it lacks a
secondary groove or canal for nerves and blood vessels. The second
and third cervical vertebrae are fused. Erethizontids have enlarged
auditory bullae and excellent hearing, but poor vision. Parocciptal
processes are short. The olfactory sense of these animals is fairly
good.
New World porcupines are nocturnal and generally live solitarily or
in pairs. An exception is Erethizon, which is known to shelter with
other porcupines in caves during the winter. Erethizontids also den
in crude tree nests, rock crevices, brush, logs, and networks of
tree roots.
Erethizontids are found in several habitat types: Coendou and
Sphiggurus are neotropical and are found in lowland forests;
Echinoprocta is found in mountain forests between 800m and 1200m
elevation; and Erethizon is found in a variety of vegetative types
including coniferous forest, open grassland, desert, canyonland, and
riparian associations.
New World porcupines eat primarily plant material; members of the
family are known to ingest conifer needles and bark, roots, stems,
leaves, berries, meadow grass, seeds, flowers, nuts, aquatic
vegetation, fruits, tubers, insects, and small reptiles. Coendou has
been known to take fruit and corn from plantations, and Erethizon
has earned a bad reputation for killing timber and ornamental trees
by stripping bark from the trunks of the trees. It is possible that
the perceived damage caused by Erethizon is exaggerated. The meat of
Coendou is eaten by South American indians and the quills of
Erethizon are used as decoration by some tribes.
Predators of erethizontids include mustelids such as martens, minks,
wolverines, ermine, weasels, and fishers. Other predators are red
foxes, coyotes, wolves, bear, mountain lions, lynx, bobcats, eagles,
and great horned owls. One porcupine predator, the fisher, has been
reintroduced to some areas of North America, where it has brought
excessively large, damage-causing populations of Erethizon under
control.
The geologic range of Erethizontidae is Oligocene to Recent in South
America, and late Pliocene to Recent in North America.
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