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Aquatic Ecology Course
Zoo 374
B=Marine Mammals
Otters
Polar bear
Dolphin
Prof.Dr.Hanan M Mitwally, Marine
Biology
Sea lions
Seals
walrus
Manatees
Prof.Dr.Hanan M Mitwally, Marine
Biology
Dugongs, or sea cows as they are sometimes called, are marine animals which
can grow to about three metres in length and weigh as much as 400 kilograms.
They are the only marine mammals in Australia that live mainly on plants. The
name sea cow refers to the fact that they graze on the seagrasses, which form
meadows in sheltered coastal waters. As dugongs feed, whole plants are
uprooted and a telltale-feeding trail is left. Dugongs are more closely related to
elephants than to marine mammals
such as whales
and dolphins,
but manatees
are their
closest
living
aquatic
relatives.
Oceanic birds spend most of their lives in or
on the water and derive their sustenance
The Albatross is almost as much a marine animal as a
whale.
They spend months wandering great distances over the
oceans.
They sleep while floating on the ocean surface, drink
seawater, and feed on cuttlefish, other small marine
animals.
They return to land only to breed
Well-known species include the wandering albatross, a
huge bird with a 3.4 m (11 ft) wingspread.
Albatrosses nest on barren islands, close to shore; usually
the nest is a depression in the ground containing a single
egg.
* Penguins are true marine animals
* They only come on shore to breed,
return to the same breeding grounds
every year
* The rest of the time they are in the
water or on the ice
* The diet of the Penguins is unremarkable; it consists of
small shoaling animals, small fish and various
crustaceans
* These animals, in turn, feed on zooplankton, which feed
on phytoplankton
As mentioned before, Most nekton are chordates, animals with bones
or cartilage. This category of nekton includes:
* Bony fish (most common)
* Cartilaginous fish (sharks and rays)
* Mammals (whales, seals, porpoises and dolphins)
* Reptiles (Turtles, snakes, iguana and saltwater crocodiles)
* Sea birds (Penguins)
Others are molluscan nekton like
cephalopods, as squid, clams and octopus
which are invertebrates, animals with no
bones. However, molluscan nekton have
no outer shells.