(Brazilian, Flat-tailed or Margin-tailed Otter)
The longest otter in the
world
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.
|