Crocodiles are large reptiles, mostly found in the tropical regions of Africa, Asia, and the Americas. They belong to the order Crocodilia, which also includes caimans, gharials, and alligators.
They are vicious reptiles known to have strong bites and a rugged appearance. There are 13 species of crocodiles, so there are many different sizes of the crocodile. The big mouth and powerful jaws of the crocodile are some of its most distinctive features.
These majestic creatures are fond of laying at river banks with their mouths wide open and this is indeed an interesting sight. What intrigues people most, however, is whether or not crocodiles have tongues.
Do crocodiles have tongues? Crocodiles have tongues, although the tongue of a crocodile does not move freely. The crocodile’s tongue is one of the features that distinguish it from an alligator. While alligators use their tongues mainly to swallow food, crocodiles use their tongues to regulate salt and body heat.
It is important to observe that, the crocodile’s tongue is not involved in the feeding process. What then is the crocodile’s tongue used for? How do they feed with a tongue that does not move?
In this article, we will have a look at the crocodile’s tongue and how it functions.
How do crocodiles swallow food without moving their tongue?
Crocodiles are different from most reptiles. Reptiles usually have mobile tongues and use them to swallow food. The tongue of a crocodile on the other hand is immobile and does not play any role during swallowing.
The tongue of a crocodile is fastened to the bottom of its mouth by a membrane, thus the crocodile can only move its tongue by pushing it forward or backwards.
To understand how crocodiles swallow without a tongue that moves about freely, you must first understand how they catch and eat their prey.
A crocodile has very powerful jaws and 24 extremely sharp teeth. Crocodiles can generate 3,700 pounds per square inch or 16,460 Newton of bite force. This bite force is 3-4 times more than what animals like the lion and tiger can generate.
Crocodiles usually stay well hidden in calm waters, patiently waiting for prey. When an unsuspecting prey comes along, usually to drink from the water, the crocodile strikes out, clamping down on them with massive jaws and a lethal bite.
The femur is the strongest bone in the human body and to break it, you will need about 4000 Newton of force. The bite force of a crocodile is equivalent to 16,000 Newton of force. This amount of force will easily shatter human bone.
After the initial lethal bite, the crocodile crushes its prey with more bites, then swallows the crushed prey, whole. Unlike other animals, crocodiles do not chew or cut off small chunks of meat at a time.
Since crocodiles can not chew their food or mix it with saliva, their tongues are not needed during feeding or swallowing.
If they don’t need their tongue to swallow food, what then is it used for?
Crocodile’s mainly need their tongue to
- Keep water from getting into their airways while they are underwater
- Regulate the salt content in their body
- Regulate their body heat
Let us now examine these three functions of the crocodile tongue.
underwater technique to keep water out of their airways
Though they can’t breathe underwater because they lack gills (the organ that’s needed to breathe underwater), crocodiles are however mostly found in the water.
Crocodiles protect their lungs by blocking water from getting into their airway while they are underwater and so, most times they come out of the water to breathe.
It is for this reason that a membrane attaches their tongue to the roof of their mouth. This position of the tongue restricts water from getting into the airway or lungs of the crocodile while it is underwater as it helps keep the throat closed.
How do they do it?
For clarity, let us have a simulation. If you open your mouth and try to breathe through your nose, it will be observed that the tongue naturally blocks your throat so that breathing through your nose will be possible. It is the same with crocodiles. Their tongue automatically blocks their throat to protect their airway when underwater.
How long can crocodiles remain underwater?
When crocodiles are inactive, they can spend an incredible 2 hours underwater. However, when there is some form of activity on their part, crocodiles can stay underwater for about an hour.
A small portion of the crocodile’s hemoglobin is the reason for the animal’s uncommon ability. The rare ability to use the bicarbonates that are formed as a byproduct of cells using oxygen and releasing carbon dioxide (metabolic process), is unique to crocodiles.
These fragments of the crocodile’s hemoglobin can unload oxygen only to cells that produce surplus bicarbonates. What this means is that oxygen is not supplied to the entire body, but only to active cells.
To regulate salt content in the body
Herein lies the main difference between an alligator and a crocodile. Crocs possess salt glands present in the hind part of their tongue. In crocodiles, salt glands are salivary glands that are modified and functions as an exocrine gland secreting salt. It is for this reason crocodiles can survive in saltwater where alligators can’t.
How do they do it?
A deeper study of this matter is beyond the scope of this article and we shall have a broader look at this. Living in saltwater is more difficult than living in freshwater especially when you put it into perspective, maintaining the ionic concentration in their body fluids.
When in saltwater, the ionic concentration of the water surrounding a crocodile will be higher than the ionic concentration of the crocodile’s body fluids.
This will bring about osmosis (the process of passage of a liquid through a semi-permeable membrane) This can threaten the life of the crocodile as the cells in its body will start draining water at a higher rate.
The salt glands in the crocodile’s tongue are modified salivary gland that has tubular lobes which secrete salts. These Lobes consist of several short, blind-ending secretory tubules which join together to form multiple interlobular ducts.
Crocs also have numerous capillaries, arterioles, and venules running through the connective tissue between their lobular ducts. The salt is carried from the salt glands to the cells of the crocodile’s body by the arterioles, venules & capillaries to maintain the ionic concentration for osmoregulation.
Crocodiles are cold-blooded animals, unlike mammals and birds. As a result of this, crocs depend on behavioral body temperature regulation methods rather than physiological means to maintain their required body temperature.
A body temperature that is maintained between 30 to 33 Degree Celsius is the preference of a crocodile. They are known to move between the warm and cool parts of their surroundings to maintain this body temperature.
To achieve this, crocodiles are usually found floating on water or lying under the hot sun with their mouth wide open. Crocodiles bask in the sun with their bodies aligned in a particular way to receive maximum heat from the sun without absorbing too much heat in their head.
During basking, crocodiles engage in evaporative cooling (sweating through their tongue) to allow their brain to cool. This process is carried out at the same time that the body rapidly absorbs heat.
Crocodiles are not common in cold areas especially because of this body temperature regulation technique.
You might also want to note that basking in the sun with an open mouth is not only done to cool the brain of the crocodile. It is more common to find crocs on land in the rain or at night lying with their mouth wide open.
This suggests that keeping a widely open mouth is also a pattern in crocodile behavior.
Do crocodiles cry? (Crocodile Fact)
‘Crocodile tears’ is a popular term but did you know that crocodiles cry? Yes, crocodiles usually shed tears while eating prey or when on dry land. Of course, nothing suggests that the tears shed while they eat prey are in sympathy with the prey.
Why do they shed tears then?
One thing has to be made clear before we continue. Crocodiles do not cry, what they do, is shed tears. There are 2 main reasons for crocodiles shedding tears:
Reason 1 – To keep their eyes lubricated when on land: Most of their time is spent on the water. This means that their eyes are always lubricated and to maintain that status on dry land, they use their tears as a form of lubricant.
When basking in the sun, their eyes tend to get dry because of the air surrounding them. This causes the tear glands in their eyes to produce tears to remain lubricated at all times.
Reason 2 – To dislodge excess salt content from their body: It is very important to crocs that they maintain the needed concentration of ions in their body fluids to avoid an imbalance in ionic concentration when compared to their outside environment.
Sometimes, there is an increase in the ionic concentration of the body fluids in crocodiles caused by the food they eat or at the point of digestion.
Their tear glands can also be triggered by this and when that happens, they shed tears to help regulate the ionic surge and maintain an isotonic environment.