Order: Carnivora
Family: Mustelidae
Genus & Species: Pteronura brasiliensis
APPEARANCE
The giant otter is the longest of all the otter species, with a length of 6
ft (1.8m), including the tail, and a weight of 76 lbs (34 kg). The females
are smaller and weigh only 57-60 lbs (26-27 kg). The tail is, on
average, 2 ft (56 cm) in length, with 2/3 of it flattened. The fur is
dense, thick, and velvety, and is highly sought after by fur traders. The
guard hairs are short, 5/16 in (8 mm) long, twice as long as the
underfur. The fur is water repellent and is a deep chocolate brown in
colour. A unique white mark is located on the throat that can be used
to distinguish between individuals. The head is round and the ears are
small. The nose is completely covered in fur, with only the two slit-like
nostrils visible. The eyes are large and acute, perfect for hunting
underwater. The legs are short and stubby and end in large webbed
feet tipped with sharp claws. The giant otter is well suited for an
aquatic life, and can close its ears while underwater.
Giant otters have a life span of 12 years in the wild, 21 years in
captivity.
HABITAT
The giant otter is found in the lakes, slow-moving forested rivers,
creeks, reservoirs, and swamps of South America. They are absent
from Argentina, Chile, and Uruguay. They are highly social animals
found in extended family groups of 10-20 individuals. They share roles
within the group, which is structured around the dominant, breeding
pair.
FEEDING
Giant otters are one of the largest predators of their region, and so
can choose from a wide variety of animals to feed on. They feed
mainly on fish, such as catfish and perch, but will also feed on crabs,
caimans (related to the alligators) and snakes. They can hunt in either
groups or alone, tending to head towards the deeper waters while in
groups. They consume up to 10 lbs (4.5 kg) of food each day, using
mostly their sense of eyesight to capture it.
In the zoo, they are fed bass, carp, tilapia, catfish, trout, and vitamin
supplements.
ENEMIES
Giant otters are at the top of the food chain, and therefore have few
natural predators. Jaguars are some of the few that have been known
to hunt them. Humans are their main enemies, at one time exclusively
hunting them for their fur. One pelt was worth a year's wages in South
America, and so giant otters were hunted by most everybody, driving
them nearly to extinction by the 1970's. Today they are very rare, with
an estimated population of only 2000-5000. Factors besides the fur
trade are keeping their numbers down. Ignorant fishers sometimes
shoot them, as they are thought to compete with the fishing industry.
Other factors include mercury poisoning caused by gold mining;
habitat loss; and the disturbance of waterways by boaters.
CONSERVATION
Much is being done to protect the giant otter. In 1973, CITES
classified the giant otter as endangered and banned all trade in pelts.
The Philadelphia Zoo opened up the first North American exhibit of
giant otters in order to increase public awareness. Finally, a sanctuary
for giant otters and other native endangered species was created in
1995. It is an 81510 acre lot on the Duroche Ranch, and was created
by the Nature Conservancy with Ecotropica.
BREEDING
Giant otters have a gestation period of 65-70 days, after which a litter
of 1-5 pups is born. The mothers give birth in underground dens near
the shore. The pups are taught to swim after 2 months and leave to
fend for themselves after 2-3 years. Giant otters are very sensitive to
human activity, and tourists boating too close to a nursing mother can
cause her so much stress that she stops producing milk; the pups
starve. Giant otters give birth annually.
RELATIVES
There are 13 species of otters found throughout the world, with the
exception of Australia and Antarctica. The giant otter is a river otter
and is closely related to the North American river otter and the
European otter.
RESOURCES CITED
1. www.otter.org
2. www.phillyzoo.org/pz0028.htm
3. otternet.com/species/giantotter.htm
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