Translation 2783

. 116
he range of these seals is restriCted to Lake :jaikal, where
they are found everywhere'.
The highest concentration of the animals •
occurs in the northerc, part•of the lake, and tho,lowest in the Louth- 79
ern part.. There are two types of migration, spring and autumn. In . -
the spring migration mot of the herd makes for the northern areas
of the lake, where the ice stays longer and the animais are able • to
moult until it finally breaks up. The autumn migration-is directed
towards the shallow waters in the northern part of the Iae, which
freeze me et quickly -- the shallowb of the 'Jelenga and Upper Angara -
river deltas and of Proval, Chivyrkuiskii, barguzinskii, and other .
are associated with the formation of autumn bays. These movements
rookeries. In summer the seals - disperse in deep yater, mostly in . .
the northern part of the lake.
In late autumn the seals (mostly adults: begin to côneentrate • .
in the northern part of the lake. Later they form .
pupping rookeries
in that region. They make special air-holes in . tue midst of hummocky
ice, through which they conte up to breathe, and they seldom appear' .
on the surface of the ice.
Long before parturition becomes due ti.e females make dens for
themselves, in places on tne ice-floes where there is a. deep layer of '
snow. The dens communicate with tee water tnrougn widened air-holes.
These snow. "huts", which are sealed up from inside, become
very strong and are almost unnoticeable externally. Sometimes two
or three of these shelters may be located on a small patch of ice, '
at
but usually they are considerable distances from one another.
A
• The pupping period of Lake Baikal seals is.fairly long, - and -
lasts for 50 or 40 days. Most of the females produce - tneir young
during . one-and-n- half or two weeks in thc.' middle of ',arch. A female
usually produces a single pup, but twins have been recorded.. Being
constantly cooped up in thL snow den, tn,. pup does not move . about
much and, feeding intensively on its motner's milk, c,rows rapidly.
Loosening of its embryonic hair covering begins at the end of its
second week of life, and it copletes the moult at the age of about
one month, while still living in the den, which at that time begins '
to collapse. After the moult the pups do not leave the half-Juined
dons, but sta;ç in tnem and continue to be fed on milk. fhe lactation,
p(.riod is fairl:, long, las n' from -tve to Lweeand- o.-half months.