BITING MECHANISM OF SNAKES
The mechanism of biting is a complicated process and it can be describes in the
following steps:
i) Opening of the mouth:
By the contraction of the digastric muscles the mouth is opened.
ii) Rotation of maxilla:
As the mouth opens the lower jaw moves forward and a rotation of the squamosal,
quadrate, and mandible in relation to each other occurs. Now the sphenopterygoid
muscles contract. This contraction results in the forward movement of the
pterygoid and up-pushing of the ectopterygoid. The upward movement of the
ectopterygoid brings a rotation of maxilla on its own axis round the lachrymal and
as a result the fang is raised and becomes directed forward. The fang is nearly
horizontal in position when the mouth remain closed, but during the opening of
the mouth to bite, the fang assumes almost vertical position.
iii) Closing of the mouth:
The closing of the mouth is brought about by the contraction of the temporalis and
sphenopterygoid muscles. The point of fang is directed backward w hile the mouth
is closed. It takes longer time to open the mouth thanto close it.
iv) Transference of veno m:
During the contraction of the digastric muscles theposterior ligament is relaxed ad
during the rotation of the squamosal bone the fan-shaped ligaments are stretched to
squeeze the wall of the poison gland. This makes the poison to come out of the
poison gland through the poison duct and the fang.
Conclusion:
Vipers (family Viperidae) possess hollow fangs on the maxillary bone at the
anterior margin of the upper jaw. These fangs connect to venom glands that inject
venom when the viper bites. The maxillary bone (upper jaw bone) of vipers is
hinged so that when the snake‟s mouth is closed, the fangs fold back and lie along
the upper jaw. When the mouth opens, the maxillary bonerotates and causes the
fangs to swing down. Because the fangs project outward from the mouth, vipers
may strike at objects of any size. Some cobras can “spit” venom at their prey; if
not washed from the eyes, the venom may cause blindness. Venom glands are
modified salivary glands. Most snake venoms are mixtures of neurotoxins and
hemotoxins. The venoms of coral snakes, cobras, and sea snakes are primarily
neurotoxins that attack nerve centers and cause respiratory paralysis. The venoms
of vipers are primarily hemotoxins. They break up blood cells and attack blood