ZOOLOGYZOOLOGY

CROCODYLUSCROCODYLUS(magar)

Diksha Sharma Sec.- B

Batch- 4 Roll no.- 620

CLASSIFICATIONCLASSIFICATIONPHYLUM CHORDATA

SUBPHYLUM VERTEBRATA

SUPERCLASS GNATHOSTOMATA

CLASS REPTILIA

SUBCLASS ARCHOSAURIE (possesses both temporal arches)

ORDER CROCODILIA (exoskeleton of bony plates,scales & tail long, laterally compressed)

HABIT & HABITAT

The world's largest living reptiles relish privacy and warm weather, and thrive in still or slow waters that provide plenty of camouflage.

Crocodiles inhabit every continent except Antarctica and Europe.

Cold-blooded, they flourish in tropical habitats where they can bask in the sun year-round.

Water provides relief from the heat and camouflage while hunting.

With a body that is symmetrical and stramlined, they are excellent swimmers.

They have very short limbs which is why they seem much slower on land.

MORPHOLOGYMORPHOLOGY

Body is covered with an exoskeleton of horny thick epidermal scales provided with dermal bony plates.

The general colour of the upper part is dark olive- brown. The head is triangular and rough at the top. The snout (long nose) is stout. Limbs are pentadactyle with 5 fingers & 4 toes. The fingers are webbed at the base and the outer toes

are broadly webbed. The tail is long & laterally compressed. There are upper & lower jaws, each contains 19 teeth on

either side.

Vertebrae are procoelous (concave at the anterior end of the centrum and usually convex at the posterior end of the centrum).

The ears are covered by movable flaps of skin. The 5th tooth in the upper jaw is the largest & the 4th

tooth in the lower jaw fits into a notch in the upper jaw.

Tongue not protrusible. There are salt glands found on the tongue.

Body 4-6 meters in length and coverd by leathery armour of osteoscutes arranged in transvers rows.

They have four chamberd heart. they don’t have any sweat glands. To release heat,

they need to have their mouths slightly opened. This is why they are often found sleeping with their mouths open.

They are able to hold their breath for a couple of hours without any damage to the body or brain.

They can also slow down their metabolism when food is scarce. As a result a large sized crocodile may only need to eat few times per month to survive.

they have what appears to be tears streaming down their eyes.They aren’t really tears though but a type of solution the body creates to help them cleanse around the eyes.

They have a valve that will pinch the nostrils closed so that water doesn’t enter them.

They continue to grow new teeth when others fall out. This is part of how they are able to live to be 70 to100 years of age.

Crocodiles will intentionally consume large rocks. This is to help balance out the needs of their digestive system. It will help to crush the foods that they have swallowed so it can be used by the body for nutrients.

REPRODUCTION For crocodiles the mating season usually will begin in July or August. They are ready to mate when they are about 8-10 years of age. The males tend to put on a great show of power and dominance with

each other. The mating will take place under the water. The females will dig at least 10 feet into the ground. They want to

make a burrow where they can deposit their eggs and prevent other predators from consuming them.

It takes about 80 days from conception for the young to hatch. The young will spend several months in the close proximity of their

mother. While she will do all she can to offer protection and direction her efforts are often in vain.

If the temperature inside the nest is below 31.7°C (89.1°F), or above 34.5°C (94.1°F), the offspring will be female. Males can only be born if the temperature is within that narrow range.

IMPORTANCEIMPORTANCE While in many cultures they have

been hunted for food or to make items out of leather.

They are also destroyed to get rid of these strange looking reptiles.

Crocodiles are known as the species that cleans up the river as they eat carcasses of other species and balance its population in the habitat.

They are key predators at the top of the food chain and eat a wide range of prey.

Threats to Crocodiles:-

a) Habitat loss

b) Hunting & Exploitation for hide

c) Hybridisation