Examples of Students Essays

Belukha – Abstract


Belukha,
white
Keith,
mammal family of dolphins
the suborder of toothed whales. Sometimes referred
to the family edinorosov.



Object
a limited fishery (used
the skin and fat). The last three decades
in Russia, the commercial hunt of Beluga whales
not conducted; annually produces several
tens of animals for the needs of the peoples of the North
and Far
East, research and
dolphinariums.



Belukha satisfactorily
transfers captivity, easy to train.
Was first introduced in the circus
Barnum
in 1861
year. Some of the specialty successfully
mastered by dolphins and Beluga whales
(deliver equipment to divers, search
lost items underwater
movie), can make them
invaluable helpers human
the study of the Arctic.



Leather with a compacted layer of the epidermis
(15 mm thickness) protects belugas from
injuries while swimming among the ice.
Hypothermia saves them a layer
subcutaneous fat up to 10-12 cm thick.



In addition
the cries of the whales emit clicks in the ultrasonic
range.
Their production involved
the system of air sacs in the soft tissues
the head and focuses the radiation special
fat pad on his forehead — acoustic
lens.
Reflected from surrounding objects,
clicks back to the white whale; “antenna”
is the lower jaw, which transmits
the vibrations to the middle ear cavity. Analysis
echo allows the animal to obtain an accurate
representation of the surrounding space.



Though
the massiveness, the whale is different
agility; it is able to float on back
and even backwards. Usually floats with
a speed of 3-9 km/h; frightened, maybe
to make leaps of up to 22 km/h With an average
speed Beluga whale emerges every
1-1,5 minutes, but is able to remain under
water up to 15 minutes. Belukha is adapted
to virtuosic maneuvers in shallow water.
If it is still “stranded” in
low tide or, with the jamb,
maybe waiting for the tide to return
in the sea.



Basis
power Beluga whale is a fish, the main
way, schooling (capelin,
cod,
polar cod,
herring,
cod,
flounder,
whitefish
and salmon
species); to a lesser extent, crustaceans
and cephalopods
shellfish.
Prey, especially benthic organisms,
belugas don’t grab and suck. Adult
individual consumes in a day, about 15 kg of food.
In the pursuit of fish (salmon for spawning)
the whale often comes in large rivers
(Ob,
The Yenisei,
Lena
Cupid),
sometimes rising up with the current
hundreds of kilometers.



Beluga
make regular seasonal migrations.
In the spring they begin to move to
shore to shallow bays, fiords
and the mouths of the Northern rivers. Letovanje have
the shores due to the abundance of food here
and higher water temperature. In addition
also, the coastal areas are convenient
“moult”, to remove dead skin
the surface layer of skin, the belugas RUB against
about pebbles
in the shallow water. Beluga whale tied to one
and the same places of letownia visiting them
from year to year. Tracking individual
individuals have shown that belugas remember
the place of his birth and path
after wintering.



In
winter time is usually kept
edge of the ice field but sometimes far
penetrate into the zone of glaciation, where the winds
and current support cracks, leads
and polynyas.
When icing large areas
making a mass migration to the South.
The hole in the ice that the belugas rise
to breathe, can be removed for a few
kilometers from each other. Beluga
support them, not giving to freeze;
they are able to penetrate the back of the ice
thickness of several centimeters.



The
never the less, the winter sometimes ends
for belugas tragically, when polynyas
lasts too thick ice or
a herd of white whales falls into the ice trap.
In winter, belugas hunts white
bear
which lies in wait for prey at sagebrush
and suppresses its blows paws. Another enemy
Beluga whales is the killer whale.



Travel
Beluga herds consisting of groups
of the two types. One is a group of 1-3
adult females (probably sisters)
and their offspring of different ages. Another
type — group of 8-16 adult males.
In pursuit of shoals of fish, Beluga whales sometimes
gather in herds of hundreds and even thousands
goals.

Beluga whales are social creatures.
For the diversity of their sound
the Americans called the white whale “sea
the Canary”
but the Russian had the idiom
“roar
Beluga”.
Researchers counted about 50
sound signals (whistle, screeching, chirping,
scream, screech, squawk,
roar). In addition, belugas use
when communicating “body language” (slaps on the water
tail fins), and even facial expressions



Common
circumpolar between 50° and 80° C. sh. a., inhabiting
the Arctic and Bering
and Okhotsk
the sea;
in winter sometimes comes to the Baltic
sea.
Isolated population exists in
estuaries
river
SV. Lawrence.