Bear Ecology
The ecology of the Andean
bear, Tremarctos ornatus,
is still being investigated, by this project and others, and there is
still much to learn.
Range & habitat:
The elusive Andean Bear
lives in the Andes Mountains. It the only species of
South American bear, found in a narrow strip running from western
Venezuela through the Andes in Colombia, Ecuador, Peru, and Bolivia,
and ending in northwest Argentina. Bear habitat can include
cloud
forests, dry forests and paramo or high grasslands. The
distribution of the Andean bear
is predominantly
restricted by geographical boundaries like deserts
(e.g. the Atacama desert accounts for the complete lack of
bear populations in Chile). Bears are an
"endangered" species in
Ecuador,
mostly due to habitat fragmentation caused by livestock farming and
logging. Farmers sometimes shoot the bears because they eat
corn (this is
illegal).
Appearance:
The Andean bear has a shorter nose than the other 7
bear species,
similar to that of a dog. The Andean bear has a long, thick black coat,
except around the muzzle, which is tawny or brown, often with white
or brown marks around the eyes (from which it gets its common name, the
spectacled bear) that may extend to the throat and chest. Not
all spectacled bears have "spectacle" markings, some have plain black
faces, which is why scientists prefer to refer to them as Andean bears.
Bear size: Male
Andean bears are
much larger
than females, with males often growing to a size of 2.2 metres from
head to toe. The largest male Andean bear ever recorded measured 2.4
metres. Males may weigh up to 200kg. Females
are much smaller, rarely exceeding heights of 1.6 metres from head to
toe. The Andean Bear is smaller than polar
bears and grizzly bears, but larger than sun bears and asian black
bears. Andean bears are just a little smaller than American
black
bears.
Bear lifespan: The
bears' lifespan in the wild is probably
rarely longer than 20 years due to the stresses of natural
life and
sporadic food availability. Andean bears may live as long
as 35 to 40 years
in captivity.
Senses:
Like all bears, Andean bears have a highly developed sense of
smell (olfaction). Their vision and
hearing senses are adequate but inferior to their sense of smell.
Bear diet: Andean
bears have a varied diet. Taxonomically they are classed as
carnivores, although they are omnivorous and
opportunistic
feeders and
in reality are predominantly vegetarian. Like all ursids
(bears) they have a sweet tooth and enjoy honey from any bees' nests or
honeycombs
they find. In the forest the bears eat palmitos (hearts of
palm), the
soft
insides of suro (Chusquea
sp.) (a kind of bamboo), the soft bases of
huaycundos (bromeliads), and various types of fruits. In the
paramo,
they eat the soft bases of puyas (Puya
sp., see photo to the right) and a huckleberry-like fruit
called mortiño (Vaccinium
sp.). With forests increasingly
being felled and replaced by cornfields, bears have developed the
taste for sweet corn or maize. Although this is not a natural
food source, in
the corn season a bear's diet consists of a large proportion of
maize.
Like all carnivores,
Andean
bears need a source of protein for tissue
growth. The bears dig in the earth in search of
beetles, worms
and insects
as a source of protein, and occasionally feed on small mammals.
In very
rare cases, in a few parts of their range, there have been incidents of
male bears attacking livestock. This is believed to be due
to a
lack
of food in the forest forcing bears to search for food elsewhere.
Unlike
felines,
the bears don’t go for the jugular, but jump
on the cow's back and take
chunks out of
the tender shoulder region while the cow is still alive. Even
if
the cow
survives this attack, it will probably be killed as its neck
or
spine snap when the bear drags it to a more sheltered spot to eat.
Andean bears are very strong and an adult male can drag a
fully-grown cow or even a bull.
Taxonomy: the Andean
bear is classified as a mammal, a carnivore, an Ursidae (bear) and
the only surviving species of the shortfaced bears, the
Tremarctinae.
Ecological Role:
Andean bears are a
keystone species, playing a major role in maintaining the dynamics of
the cloud forest ecosystem they live in. The bears in the
Intag region of Ecuador are known
to rip the bark off Brunelia trees.
This causes the premature death and fall of the
trees, creating clearings in the forest, allowing light to get
through to the undergrowth, which permits smaller trees to
grow and therefore promotes new life in the forest. Andean
bears are
very agile and often climb trees in search of bromeliads and fruits.
In doing this, and jumping from
tree to tree, they may break branches which
again allows light to pass down to the undergrowth,
and so promotes new growth. By eating
fruits of the forest, the bears disperse seeds to other parts of the
forest in their faeces. This is another method by which
the Andean bear promotes natural regeneration of the cloud forest
ecosystem, which is vital as the "lungs" of the planet and
to maintain the natural water cycle.
This role of the bear as
a keystone species in its ecosystem means that it is important that the
Andean bears are protected and supported with conservation
initiatives
if the cloud forest itself if to be saved, along with all the other
wildlife it supports. To understand what needs to be done to
conserve the bears, we are studying bear
behavior.
Andean
Bear Conservation Project: Bear Ecology
Ecology of the Andean bear, including bear habitat, range, diet, size
and lifespan of the bears and their role as a keystone species.
