Baikal Seal or Nerpa
The Baikal seal
belongs to the Mammalian Order Pinnipedia, in the family Phocidae.
Other members of Phocidae include elephant seals, gray seals, and
monk seals. Phocids are referred to as true seals. They are
distinguished from other pinnipeds by their inability to support
their body using their hind limbs. The Baikal seal's scientific
name, Phoca sibirica, means "seal belonging to Siberia".
This seal is called the "nerpa" by inhabitants of Siberia. Nerpa
means "seal" in Russian.
The Baikal seal is the
only freshwater seal species, and is endemic to Lake Baikal of
Siberia. The Baikal seal is a small species of seal. Adult seals
grow to about 4.5 feet in length, and weigh from 110-290lbs. Males
are slightly larger than females. Baikal seals are silvery gray in
color, although some are spotted. Baikal seals share a variety of
morphological characteristics with arctic seals. Scientists have
concluded that Baikal seals are close relatives of the ringed seal.
It is estimated that Baikal seals diverged from ringed seals about
500,000 years ago. They have larger foreflippers than ringed seals,
and two more liters of blood than ringed seals. The larger quantity
of blood allows the seal to dive for longer periods of time. The
Baikal seals' evolutionary relationships to other seals may be
clear, but the way they reached Lake Baikal is still a mystery.
Lake Baikal lies hundreds of miles inland from any ocean.
Scientists hypothesize that prehistorically the Arctic Ocean
extended farther inland. Seals were capable of migrating farther
Baikal seals are the
only seal species to live entirely in freshwater. Lake Baikal is a
395 mile long lake in eastern Siberia, bordering Mongolia. It is
the world's oldest lake, dating back 25-30 million years ago, and
the world's deepest lake, reaching an estimated depth of 5,315
feet. Twenty percent of the earth's unfrozen freshwater is held by
A variety of aquatic
animals are endemic to Lake Baikal's highly oxygenated water
system. The Baikal seal's diet consists of these endemic fish
species. These include a few species of bullhead, and the
golomyanka. The golomyanka is pearl colored, deep lake fish. It is
extremely rich in Vitamin A, containing a content of about thirty
percent. This fish does not swim in schools, preventing its
classification as a food fish. As a populous fish of Lake Baikal
that is not netted by human fishermen, the golomyanka is the staple
of the Baikal seal's diet.
Baikal seals are
solitary animals. During the winter months while the lake is
frozen, seals maintain breathing holes. As the ice begins to thaw,
seals congregate around larger holes to hunt. Breeding occurs in
the water, during late spring. Females experience a period of
delayed implantation. Gestation lasts nine months. A single pup is
born on the ice in late winter, between February and March. A
newborn pup weighs 7-8lbs at birth and is about three feet in
length. They are covered in a fluffy white natal fur, called lanugo.
This white fur is shed after six weeks, accompanied by the growth of
adult fur. Pups are weaned 2-3 months later. The weaning is
synchronous with the lake ice melting, and since the southern lake
melts faster than the northern lake ice, young seals of the southern
seal population are smaller at weaning age than northern seal pups.
Male seals reach sexual maturity at 4-7 years. Females mature
sexually at 3-6 years.
Baikal seals have been
hunted by local inhabitants for thousands of years. Their meat was
once used as a human food source, but is now used to feed
livestock. The pelts of young seals are used to make clothing.
Local governments regulate seal hunting. The bioaccumulation of
pollutants in Baikal seals poisons many seals. Canine distemper
outbreaks, contracted from domestic dogs in the area, have
occasionally claimed the lives of thousands of seals. Since seals
eat noncommercial fish species, the animals do not compete with
human fishermen. The current population of seals rests at about
80,000 individuals. Due to the endemism of this species, if special
concern is not given to its natural habitat this species could