Let's look at a dog's skull - a familiar animal,
to get an idea of the basic structure of a skull and jaws and the
The upper jaw is formed from the base of the
skull. The lower jaw is made up of two bones which are loosely
fused at the front
and on each side (left and right) is hinged behind with muscles
to the back of the skull. Movement of these muscles works the
lower jaw up-and-down and in some animals sideways as well.
Teeth are anchored in sockets on both upper and lower jaws and inside are supplied with nerves. Teeth are of several sorts, each shaped for handling different sorts of food. Basically teeth comprise two incisors
(for cutting and slicing) at the front on each side of the upper
and lower jaws. (This means four upper and four lower incisors).
Behind the incisors on each side there is a canine tooth (for
piercing, stabbing and holding); thus there are four canines. Behind the
canines are two premolars and two molars all of which are shaped
for grinding and chewing.
Dogs are carnivorous animals and their
canines, like those of cats and all carnivores, are long and
pointed. Wild dogs such as the dingo, and other carnivores, catch
live prey mainly other vertebrate animals and the canines grasp,
jab and hold the prey
In the dog the incisors are comparatively
and unspecialised. However in herbivorous animals the incisors
are variously modified and specialised for cutting and tearing
grass and other plants or for browsing on higher plants.
killing their prey with the canines, dogs and carnivores tear,
chew and grind the prey with their molars which have crowns and