Vertebrates are the fastest running, best swimming and farthest flying
creatures on earth. The main factor underlying all of these abilities
is the presence of skeletons made of hard materials such as the bones
that do not lose their shape. These bones provide tremendous support for
contracting and flexing muscles, which bring about continuous movements
through moving joints.
However, invertebrates move at much lower speeds, in comparison with
vertebrates, due to their boneless structures.
are invertebrates that do not have bones in their bodies despite being
called fish. They have extraordinary abilities to manoeuvre because of
a very interesting system. Their soft body is covered with a thick mantle
under which large amounts of water are drawn and flushed out by strong
muscles and that enables them to escape backwards.
This mechanism in cuttlefish is highly complex. On both sides of the
animal's head are pocket-like openings. The water is drawn in through
these openings into a cylinder-shaped cavity inside its body. Then, it
jets out this water from a narrow pipe immediately under its head with
great pressure, which enables 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).
|Cuttlefish receive great help
during hunting from the tentacles in its mouth. These whiplike tentacles
normally remain coiled in pouches beneath its arms. When the fish
encounters a prey, it unleashes them and snatches up the prey. The
fish relies on its adequately designed arms (eight in total) to take
care of the rest. It can easily tear a crab to bits by using its beak.
The cuttlefish uses its beak with such mastery that it can neatly
puncture the shell of a crab and rasp out the meat with its tongue.36
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.
The inner skin of the octopus is composed of many layers of muscles one
on top of another. They constitute three different types of muscles called
longitudinal, circular and radial. These structures enable various movements
of the octopus by balancing and supporting one another.
When flushing water out, the circular muscles contract lengthwise. However,
since they have the tendency to maintain their volume, their width increases,
which would normally elongate the body. In the meantime, the stretching
longitudinal muscles prevent the elongation. The radial muscles remain
stretched during these happenings that cause the mantle to thicken. After
the jet propulsion, the radial muscles contract and shrink the length,
which causes the mantle to become thinner, and the mantle cavity to be
filled with water again.
The muscular system in the cuttlefish closely resembles that of the octopus.
However, there is an important difference: the cuttlefish has a layer
of tendons, called the tunic, instead of the longitudinal muscles of an
octopus. The tunic is composed of two layers that cover the inside and
outside of the body just like the longitudinal muscles. In between these
layers are the circular muscles. The radial muscles are situated in between
these, in a perpendicular orientation.
"…The kingdom of the heavens and the earth and
everything between them belongs to Allah. He creates whatever
He wills. Allah has power over all things."
(Surat al-Ma'ida: 17)
The reactive swimming
systems, ink discharge-based defensive methods, the acute vision
and the colour changing skin abilities that cuttlefish have are
perfect examples of creation.
||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 km/h). 37
||The octopus bends its body by contracting
either one of the two longitudinal muscles, which enables it swim
in the water.
The cuttlefish also has radial and
circular muscles as in the octopus, but instead of the octopus'
longitudinal muscles there is a fibrous layer in the cuttlefish.
This layer prevents its body from elongation when both the muscles
contract as well as providing a sturdy base for the radial muscles.
Shown in the figure are the jet propulsion cycle
and sections of the cuttlefish. The cycle begins with enlargement
(1). The outside diameter of the body is enlarged by 10% of the
normal size, which increase the volume of the mantle cavity by about
22%. Water enters from the openings on both sides of the head passing
through the funnel-shaped pipe. When the maximum enlargement is
reached, the diameter of the body is reduced to 75% of normal size
Pressure in the cavity suddenly increases and pushes the inner
tap on the mouth of flushing-out pipe, which closes the water intake.
Nearly all the water (approximately 60% of normal body size) is
forcefully expelled out through the pipe. The body recovers its
normal shape by the intake of water (3).
Any further contractions could easily harm the creature. The jet
propulsion lasts about one second and can be repeated 6 to 10 times
in a row, including suction time. When swimming slowly the body
of the cuttlefish contracts to 90% of its original size.
||The eye structure
of a cuttlefish is extremely complex. It can focus the pupil by bringing
the lens nearer to the retina. It can also adjust the volume of light
taken into the eye by closing or opening the little lids beside the
eye. The presence of such highly complex organs in structures of two
completely distinct species such as humans and cuttlefish cannot possibly
be explained by evolution. Darwin also spoke about this impossibility
in his book.38
Under the skin of
the cuttlefish is arrayed a dense layer of elastic pigment sacs
called chromatophores. By using this layer, they can change the
apparent colour of their skin, which not only helps in camouflage
but also acts as a way to communicate. For instance, a male fish
can take on a different colour when mating than that it would take
on when in a fight with a challenger.
When a male flirts with a female,
it takes on a bluish colour. If another male comes by during this,
it gives a reddish colour to the half that faces the other male.
Red is the warning colour used during a challenge or an aggressive
A thin layer of skin that surrounds
the arms and the body further supports the reactive swimming system
of the cuttlefish. The fish floats in the water by means of waving
this curtain-like membrane. The arms, on the other hand, function
to balance the body during the floating. They also work for braking
The reactive swimming systems of the octopus and the cuttlefish
actually function according to a principle that resembles jet planes.
Through a closer examination, it is obvious that their muscular
systems have been designed in the way most suited to them. It is,
of course, absurd to assert that such complex structures could have
been formed through coincidences.
There is an
equally flawless design in the reproductive systems of cuttlefish.
The eggs of these fish have sticky surfaces that enable them to
adhere to cavities in the deeps of the sea. The embryo consumes
the nutrients provided inside the egg until it is ready to hatch.
The embryo breaks the egg casing with a small brushlike patch on
its tail. This feature disappears shortly after hatching.39
Every little detail has been designed and functions as it is designed
to do. All of this miraculous creation is nothing but an expression
of the infinite knowledge of Allah.