·Crocodiles evolved about 200 million years ago from the Archosaurs. They lived at the same time as the dinosaurs and probably even ate them! They have survived for all that time as the top predator.
·Crocodiles are reptiles that live both on land and in water. Like other reptiles, they breathe air.
·Scientists can tell the age of a crocodile by looking at the bones in their scales. Just like a tree, crocodile bones have growth rings. By counting these rings, they know that male crocodiles can live up to 70-100 years old.
·Crocodiles are "cold-blooded". To get warm they lie in the sun. To cool down, they lie in the shade with their mouths wide open or laze in the water. To control their body temperature, crocodiles control the blood flow inside their bodies. They can 'shut down' blood flow or speed it up.
·A 3.5m crocodile has brain the same size as a walnut. Despite this they are intelligent and have very good senses for finding prey and learning quickly.
·The crocodiles jaw can open and shut but not move from side to side. Very powerful muscles snap the jaw closed when it grabs prey. The muscles that open the jaw are not as strong.
·To swim, the crocodile swings its powerful tail from side to side. Its legs are held against the body. Both feet have claws but the back feet are webbed. They can be used to swim backwards.
·Crocodiles can swim long distances and stay underwater for up to 5 hours. On land, crocodiles can move quickly (up to 80 kilometres per hour) although this is only over short distances as they tire quickly.
·Saltwater crocodiles live in both salt water and fresh water.
·Female crocodiles reach sexual maturity at around 8 feet and 8 years of age and a male at about 10 feet and ten years.
·Female crocodiles rarely grow larger than 10 feet.
·Male crocodiles can weigh over a ton and measure over 16 feet in length.
·Crocodiles have very good vision, they can see almost 180 degrees but can't see anything below their nose.
·Crocodiles have three eyelids: two leathery protective eyelids and one clear or translucent one.
·Saltwater crocodiles will fight each other in preference to sharing food.
·A female crocodile will come up to the surface of the water and do a very deep, throaty growl to alert the males that she is ready to mate, little scent glands under her throat will exude a sexual fragrance.
·Crocodiles will mate for a period of months, and seem to enjoy it.
·A female crocodile instinctively knows whether it will be a wet season or a dry season.
·A female crocodile will build a big compost nest, which can be quite large, a metre or two high.
·Female crocodiles wait until they feel the monsoon coming, as soon as it does, they deposit their eggs. The female will use her back feet to make a perfect hollow, and then they go into a trance-like state to lay 60-80 eggs.
·A baby crocodile gender is determined by how deeply the eggs are buried in the nest and the temperature.
·A female crocodile will defend its nest to the death from any and all animals.
·When the mother crocodile hears the babies calling, she runs over to dig them out of the nest. She then carries her babies safely to the water in her mouth.
·Crocodile eggs and baby crocs are eaten by water pythons, long-necked turtles, birds and other crocodiles. From 500 eggs layed in the wild, only about 2 or 3 will become adult crocodiles.
·Crocodiles can live for months without eating because they do not use much energy.
·Crocodiles communicate with sounds and body language. To growl, the croc snorts air through the throat or nostrils. The sound is like an idling outboard motor throwing a spray of water into the air from the crocodiles back. Baby crocs 'chirp' when they are ready to hatch. Crocodiles also communicate through their behaviour. Males fight to set up their territories.