Compiled by ‘Kostur’
your Knowledge' Series:
Animals Move Under Water
animals use all manner of methods, including paddles and propellers, body
undulations and jet propulsion, to force their way through water.
Jellyfish and the larvae of sea anemones move with a pulsating bell,
octopus and squid squirt water from a funnel, scallops clap their shells
together, and lobsters and prawns escape predators by bending and flexing
their tales and shooting backwards - all forms of jet propulsion.
Many bony fish, sharks and sea snakes move with S-shaped
undulations that pass from head to tail pushing the animals forwards. Some
microscopic animals move with a whip-like flagellum that also works by
passing an S-shaped wave from base to tip. Skates, squid and cuttlefish
create S-shaped waves in the fins alongside their body. Other fish like
'gurnards' crawl across the sea floor on modified pectoral fins, and
Of the amphibians, newts use their flattened tail to move like
fish, but frogs and toads push with powerful back legs and webbed feet.
Some aquatic birds such as 'cormorants' have webbed feet that move
alternately when at the surface and together under water.
Crocodiles have powerful tails which they move from side to side.
Marine mammals such as whales and dolphins, move with an up and down
movement of the body, while the tail flukes are kept horizontal to give
maximum thrust. Penguins and sea turtles literally fly under water. The
movement of their flippers is similar to the
flapping of a flying bird's wing, except that there is power in
both the upstroke and the downstroke.