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The Anatomy of the tortoise

What is a tortoise?

Tortoises or Chéloniens belong to the class of reptiles. Considered as the the oldest alive reptiles, they appeared on Earth approximately 200 million years ago.

Tortoises are reptiles with a collected shape.
By their carapace, characteristic, it is difficult to confuse them with other animals.

Tortoises are ectothermes. They haven't an internal boiler, as human beings for example, and remain dependent on temperature of the outside environment.

The Carapace

It is a stiff structure which protects the body of the tortoises as an armor.
The carapace is subdivided into two parts:

Carapace d'une Tortue

The scales of the scute

a - Nucal
b - Marginal
c - Vertebral
d - Costal
e - Caudal

The carapace is constituted by two layers.
The most superficial is formed by scales that give to the animal its characteristic color.
Underneath scales, are osseous patches connected between them by cut edges called sutures.

How to measure a tortoise?
It is necessary to estimate what we call the linear length of the scute, that is the length from an extremity to other of the carapace.


The limbs

In ground tortoise, the limbs are collected and strong, capable of raising the weight of the body and the heavy carapace.
Fingers, generally in the number of five, are welded and only nails can be distinguished.
On the contrary, in aquatic tortoises, fingers are well separated.


The breathing system

Tortoises possess two lungs which are placed under the scute, next to the vertebral and costal patches.
Lungs are separated from other organs by a membrane.
Tortoise inspires the air by the nostrils which reaches up to lungs.

Warning! A tortoise who overturns is a frequent accident.
If the animal does not succeed in recovering on its legs, the weight of organs compresses lungs and the tortoise dies suffocate.


The senses

Vision

The eye is protected by three eyelids which close from bottom to top.

Hearing

Tortoise has no extern ears, however it hears perfectly and perceives the vibrations of ground or water.

Smell

Tortoise possesses a sense of smell enough developed to analyze its food: the animal will smell it repeatedly, recognize it by smell and finally take a little bite to taste it.