Page 106 - Design in Nature

104 DESIGN IN NATURE

The cuttlefish whose
scientific
nomenclature is
Loligo Vulgaris are the
smallest among their
species. Their reactive
swimming system
enables them to move
at speeds in excess of
nineteen mph (30
37
km/h).

it to move swiftly in the opposite direction due to reactive forces.
This swimming technique is highly appropriate in terms of both speed and
durability. A Japanese cuttlefish, called Todarodes Pacificus, in their migration
of 1250 miles (2000 kilometres) travel at about 1.3 mph (2 km/h). For short
distances, it can accelerate up to 7 mph (11 km/h). Some species are known
to exceed 19 mph (30 km/h).
The cuttlefish can avoid its predators through very swift movements as a
result of these fast muscular contractions. When their speed alone is not
enough for safety, they squirt a cloud of dense, dark coloured ink that is
synthesised in their bodies. This ink surprises their predators for a few
seconds, which is usually enough for them to escape. The undetectable fish
behind the ink cloud leaves the area immediately.
The defence system and reactive swimming styles of cuttlefish also work
for them during hunting. They can attack and chase their prey at high speeds.
Their immensely complicated nervous system regulates the contractions and
flexing necessary for their reactive swimming. Accordingly, their respiratory
systems are also in ideal condition, which provides the high metabolism that
is needed for the jet propulsion.
The cuttlefish is not the only animal swimming by means of a reactive
system. Octopuses also utilise this system. However they are not active
swimmers; they spend most of their time wandering over rocks and gorges in
the deep sea.