Like humans and many other birds and animals, felids (of which the tiger is one) have an endoskeleton, meaning that it is inside the body (as opposed to an external shell). Its skeleton comprises hard, strong bones held together by ligaments, rather than cartilaginous structures (as is the case with sharks, for example). The internal organs are then protected within this sturdy structure.
The structure of the skeleton of a tiger is similar to that of other big cats in the wild, particularly the lion. The details of the bones, ligaments and how they have been put together reveal much about the habits and make-up of this extraordinary creature.
The skull is a beautifully designed creation. Not only does it protect the eyeballs and the brain, but it is also built in a way that allows the tiger to have maximum strength in its jaw, which is essential considering its hunting methods and its carnivorous diet. The skull is short and rounded, investing all of the support and power into the teeth and jaws. In addition, where humans have a skull septum made of membrane, a tiger’s septum is made from hard bone, separating the cerebrum and cerebellum and protecting the brain more effectively.
The jaws cannot move from side to side, but only up and down, which adds to the strength of the downwards clamping. Tigers have 30 teeth, which is considerably less than many other mammals, including human beings. However, these teeth are specialised; designed specifically for hunting, clamping and tearing at the meaty prey of the animal. The canine teeth of the tiger are larger than those of any of the other wild cats, reaching lengths of almost 10 centimetres. These teeth are very sensitive, filled with neural receptors and enabling the tiger to kill its prey quickly and effectively. This reduces the suffering of the prey as well as the amount of energy that the tiger needs to invest in each kill. Then, the back teeth (carnassials) slice the meat off of the carcass of the catch.
The longer hind legs of the tiger enable it to jump powerfully, covering up to 10 metres in a single leap. Their forelegs have a solid bone running through them, which reinforces them and makes them able to support a massive amount of muscle tissue. This means that they are as strong as possible, which is important as the tiger uses these forelimbs to grab and hold onto its struggling prey, even when the hunter is running at high speeds. The collarbone of the tiger is particularly small in comparison to the rest of the skeleton and in comparison to other endoskeletal mammals. This enables it to achieve longer strides without hindrance.
Another skeletal feature that gives the tiger extra strength and flexibility is its spine, which has 30 vertebrae (as opposed to our 25) and extends to the very tip of the long tail.
The internal organs include:
Lungs – respiration
Heart – circulation of blood
Liver – processing of chemicals
Stomach – breakdown of food
Kidney – filtering of blood and removal of waste products
Intestines – breakdown and digestion of food
Bladder – holding of urine until ready for excretion