They outlived the dinosaurs but these hunters are anything but elderly!
Crocodiles are often described as living fossils, but despite the fact that their body shape hasn’t changed much in the last 200 million years, they are actually some of the most sophisticated reptiles on Earth.
Like all living reptiles, they are cold blooded but that doesn’t make them sluggish. Crocodiles have a four-chambered heart and muscles that mimic our diaphragm to ensure they can quickly pump oxygen around their bodies for explosive bursts of speed.
Crocodiles are ambush predators; their preferred tactic is to lurk in the river with just their eyes and nostrils visible above the surface and burst out of the water to surprise animals that have come to the bank to drink. If their initial lunge fails, they can chase prey over land at speeds of 17km/h (10.5mph). The galloping gait of the crocodile was dismissed as a folk legend for many years, simply because hardly anyone who witnessed it lived to tell the tale.
Once a crocodile has grabbed its prey, it will drag it into the water and pull it under. Crocodiles need air to breathe but they can hold their breath for 30 minutes and drowning your prey is easier and more reliable than risking it escaping if you unclamp your jaws.
Crocodile teeth are only designed for gripping and puncturing; they have no incisors or carnassials to slice meat off a carcass. Instead they will grip a chunk of flesh with the front teeth and spin violently on their long axis to twist off a bite-sized piece. Crocodiles don’t have lips so they can’t seal their mouth shut when eating. This means they can’t swallow food underwater without drowning themselves so each torn off mouthful has to be brought to the surface and tossed into the back of the mouth.
When food is scarce, their cold-blooded metabolism allows crocodiles to go for as long as two years without eating at all. This, combined with their ability to scavenge rotting meat, was probably what allowed them to survive the event that killed the dinosaurs.
No.2 Fact – Tongue – A crocodile can’t stick its tongue out of its mouth because it is anchored to the floor of the mouth all the way along.
No.3 Fact – Salt glands – Special glands on the top of the tongue allow crocodiles to excrete salt that builds up in their blood in saltwater environments.
No.4 Fact – Jaw muscle – The massive muscle and its placement a long way forward of the hinge provides a bite pressure almost twice that of a great white shark.
No.5 Fact – Eyes – Mounted on the top of the head to allow it to watch the bank while almost submerged. A nictitating membrane protects them underwater.
No.6 Fact – Tail muscle – Saltwater crocodiles can swim at 28km/h (17mph) for short bursts. An Olympic swimmer manages 8.6km/h (5mph).
No.7 Fact – Scales – Crocodiles can’t sweat but their scales have blood capillaries within them to let them shed heat.
No.8 Fact – Ears – Crocodiles have sharp hearing, protected by flaps that can be raised or lowered.
No.9 Fact – Stomach stones – Crocodiles swallow stones as they get older to counterbalance the weight of the head and keep them level when swimming.
No.10 Fact – Webbed toes – Crocodiles swim with their legs tucked in to reduce drag, but webbed feet allow for sudden turns and a boost in shallow water.