Graphics Reference
In-Depth Information
of more “typical” fish, they are so distinctive as to be worthy of separate study.
However, to describe them fully and appreciate their peculiarities would take
more space than is available here. Fish such as hagfish, lampreys, seahorses,
and sea dragons are perhaps among the most exotic of these.
Fish Animation
Fish may be more primitive animals than either birds or mammals, but though
the range of actions for fish may be more limited than either those of birds
or mammals, they do possess the ability to undertake a range of actions,
including a number of different modes of swimming. These various swimming
actions may be determined by a range of stimuli: feeding, migration, mating,
display, and defense. The different forms of movement are generated through
the use of different parts of the fish. These may be similar across a broad
spectrum of species, but there are variations between species. Eels depend
more largely on an undulating action; rays use their elongated pectoral fins
that have developed into wing shapes in a similar undulating fashion that
creates lift and forward momentum.
Maneuverability is achieved by the use of a series of fins in combination
to create the most delicate of actions that enable some fish to rotate their
bodies, pivoting around their center of gravity and creating a turn so tight
that they are able to maintain their overall position within the water. Some
fish are even capable of fin actions that enable them to swim directly
backward without the need to turn; other fish, such as sharks with their rigid
pectoral fins, are incapable of such actions.
In general, powered locomotion may be generated from the caudal in (the
tail), groups of paired fins, and the undulating action of the body. Other than
swimming to get from A to B, fish move to in particular ways to undertake
particular activities such as feeding or courtship.
Fish that root in the silt to get to the food that lives there often use their
pectoral fins to make fine adjustments in their forward and backward
movement and to create a downward tilt. Archer fish use the pectoral fins in
a similar manner to create an upward tilt as they position themselves to hunt
insects from overhanging branches by spitting out a column of water. Female
salmon use their paired fins to roll on their sides while using their large,
powerful caudal in to excavate depressions in the gravel of streams in which
they lay their eggs. They then rapidly oscillate their bodies, creating very
powerful downward forces that clear the gravel while only slightly moving
the fish forward.
The mouth movements of fish also vary a great deal depending on the species
of fish. Predators feeding on other fish and that use speed to catch their prey
tend to use a snapping action, grabbing a fish as they lunge forward. Fish
that use ambush instead of chase, such as catfish, quickly open their large
mouths, thereby creating a strong current that helps them gulp down any
