Image: Dr Matt White with the reconstructed skull of Confractosuchus sauroktonos and a modern crocodile. Australian palaeontologists have revealed that dinosaurs were once on the menu of crocodiles.
A new species of crocodile that lived about 95 million years old was discovered in Australia, and researchers discovered it ate a dinosaur as its final meal.
Crocodiles
Well, crocodiles share a heritage with dinosaurs as part of a group known as archosaurs (“ruling reptiles”), who date back to the Early Triassic period (250 million years ago). The earliest crocodilian, meanwhile, evolved around 95 million years ago, in the Late Cretaceous period.
There are two main reasons. First, crocodiles can live for a very long time without food. Second, they lived in places that were the least affected when the asteroid hit Earth.
About 250 million years ago, the archosaurs split into two groups: a bird-like group that evolved into dinosaurs, birds, and pterosaurs, and a crocodile-like group that includes the alligators and crocs alive today and a diversity of now-extinct relatives.
Australia is home to two species of crocodiles, the Estuarine Crocodile and the Freshwater Crocodile. Both belong to the reptile family Crocodylidae (the 'true crocodiles'), members of the sub-class Archosauria.
In fact, birds are commonly thought to be the only animals around today that are direct descendants of dinosaurs. So next time you visit a farm, take a moment to think about it. All those squawking chickens are actually the closest living relatives of the most incredible predator the world has ever known!
Unlike many other animals on this planet, crocodiles and alligators have no finite life span. Instead, they continue to live and grow unless affected by their environment through a lack of food, disease, accidents, or another large predator. Instead of aging biologically, alligators continue to simply grow in size.
Fossil records suggest that at one point in history, there were more than 3,000 types of sharks and their relatives. Sharks managed to survive during extinction events when the ocean lost its oxygen – including the die off during the Cretaceous period, when many other large species were wiped out.
Crocodiles have cold blood
Neither of these factors was efficient during the cold and dark conditions following the Yucatan meteor impact. Crocodiles have cold-blooded metabolisms, which means they were able to live for long periods of time in severe darkness, cold, and with very little food.
Today's birds are the last of the dinosaurs, descendents of ancestors that didn't just survive this mass extinction, but evolutionarily exploded into thousands of species distributed around the world.
Crocodiles relatives are believed to have existed either before dinosaurs or right when dinosaurs first appeared! Crocodile ancestors date back 240 million years to the Triassic period, that's the same era that dinosaurs first began to flourish.
Sixty-six-million years ago, a nearly nine-mile-wide asteroid collided with Earth, sparking a mass extinction that wiped out most dinosaurs and three-quarters of the planet's plant and animal species. Now we're learning that the Chicxulub asteroid also generated a massive “megatsunami” with waves more than a mile high.
Plant life consisted mostly of ferns, conifers and small shrubs. Animals included sharks, bony fish, arthropods, amphibians, reptiles and synapsids. The first true mammals would not appear until the next geological period, the Triassic.
Keeping crocodiles as pets
To keep your crocodile healthy you must give it the right food and water. In the wild, crocodiles eat insects, fish, small frogs, lizards, crustaceans and small mammals. In captivity, do not feed crocodiles chicken or beef only. Food needs to be chopped to a size that is easy to eat.
According to research scientists, Deinosuchus was the apex predator of its environment. It fed on dinosaurs, sea turtles, large fish, and terrestrial and aquatic animals that were large enough to be consumed. Like modern-day crocodiles, Deinosuchus performed the death roll on its prey.
“It would be a gigantic failure for humanity that would affect everything from coral reefs to food security and climate change. Once sharks are gone, there is nothing we can do to replace the critical role they play in the balance of the oceans."
Birds: Birds are the only dinosaurs to survive the mass extinction event 65 million years ago.
“It's a great mystery,” Elizabeth Sibert, a paleobiologist and oceanographer at Yale University, told Science News. “Sharks have been around for 400 million years. They've been through hell and back. And yet this event wiped out (up to) 90% of them.”
To date, there's only one species that has been called 'biologically immortal': the jellyfish Turritopsis dohrnii. These small, transparent animals hang out in oceans around the world and can turn back time by reverting to an earlier stage of their life cycle.
But how quickly can they run? Most crocodiles can achieve speeds of around 12 to 14 kph for short periods, which is somewhat slower than a fit human can run. Don't believe the hype - if you're reasonably fit, you can definitely outrun a crocodile!
SEAGOING CROCS
Unlike alligators or caimans, crocodiles have functional lingual salt glands for expelling sodium chloride and a fairly impermeable lining to their inner mouth, which makes them inherently hardier than their relatives in seawater.
Variables such as temperature, food sources, and oxygen levels are all factors that might impact dinosaur survival. Because dinosaurs lived in much warmer climates millions of years ago, many experts doubt they could even survive today.
Leptocyon was the first true canine (that is, it belonged to the caninae subfamily of the Canidae family), but a small and unobtrusive one, not much bigger than Hesperocyon itself.
Although that would be fascinating, the answer is almost definitely no. While there's only one generation between you and your grandparents – that is, your parents – there are many millions of generations between today's birds and their ancient dinosaurs ancestors.