Dexmo

Animal Dental Arrangements

Mammalian teeth can be divided into four different types: Incisors (I), Canines (C), Premolars (P) and Molars (M) depending upon their position in the jaw. The dental formula expresses how many of each teeth a particular animal has. All domesticated mammals have two sets of teeth: a deciduous set in young animals, which is gradually replaced by the permanent teeth present in adults.

The formula is usually expressed like a "fraction" the first (top) number refers to the upper teeth and the second (bottom) to the lower. Starting in the centre of the mouth at the front (in the middle of the incisors) each formula works around one side of the mouth e.g. left or right. Therefore I+C+P+M has to be doubled to work out the total number of teeth.

The dental arrangement of Permanent teeth in a standard mammal:

I: 3/3     C: 1/1     P: 4/4     M: 3/3     x2  =  44

No mammal has more than 44 teeth

The dental arrangement of Deciduous teeth in a standard mammal:

I: 3/3     C: 1/1     P: 4/4     M: 0/0     x2  =  32

Note, similar but lack of Molars, in many cases the deciduous arrangement can be calculated by: permanent teeth – molars.

CARNIVORES - Brachydont

Canine  Dog (permanent)

I: 3/3     C: 1/1     P: 4/4     M: 2/3     x2  =  42

Feline  Cat (permanent)

I: 3/3     C: 1/1     P: 4/4     M: 3/2     x2  =  34

HERBIVORES - Hypsodont

Equine - Horse (permanent)

I: 3/3     C: 1/1     P: 3-4/3     M: 3/3     x2  =  40 or 42

Ruminant  Cow/ Sheep (permanent)

I: 0/3     C: 0/1     P: 3/3     M: 3/3     x2  =  32

*Ruminants have a dental pad to replace their upper Incisors/ Canines.

OMNIVORES Brachydont

Porcine - Pig (permanent)

I: 3/3     C: 1/1     P: 4/4     M: 3/3     x2  =  44

There are species differences in some animals and even in some individuals.

Rodents (rats/mice etc.) and Lagomorphs (rabbits etc.) have no Canines (front teeth are Incisors) with a large diastema (gap) between the front and back teeth. 

The variation in the horse formula is due to the first Premolar sometimes called the "wolf tooth" which is present in the upper jaw of some individuals.

Not sure why some of that is crossed out! :)

0 votes WildlifeTraveller On 16.1.2009

Hi Wildlife Traveller

We are not sure either, but will have a look to see if it is a bug.

0 votes keyboardsleeper On 16.1.2009