Graphics Reference
In-Depth Information
FIG 4.83
The behavior pattern of a
fish swimming by undulation.
However, many fish and some snakes create their swimming action to
propel themselves through water using an undulating motion of their
entire bodies.
Of course, unlike fish, snakes have the ability to swim both on the surface of
the water and submerged using this kind of undulating action.
We know that different fish have slightly different patterns of undulating
action and the level of movement varies from species to species, but they
all share some common traits within such actions. The action begins at the
head of the fish and progressively makes its way along the body length. For
most fish the amplitude of the wavelength created by undulation increases
as it progresses from the tip of the nose toward the tail. Eels of all types have
the most extreme undulating action, and their particular form of undulating
swimming makes them quite capable of swimming both forward and
backward with equal maneuverability and strength. The pectoral fins have
become rather small and ineffectual, while the dorsal, caudal, anal, and ventral
fins have become a single continuous fin that aids the body's undulating
action.
FIG 4.84
The amount of undulation
within a swimming action varies
within types of fishes depending on
their individual physiognomy.
The distance a fish travels during a single cycle of undulation is known as its
stride length, which varies from species to species.
