Archosaurs, known as the “ruling reptiles,” were divided into three groups: the crocodiles, the dinosaurs, and the pterosaurs. Scientists believe that the crocodile evolved from an animal that lived in the water; into one that climbed onto the land and eventually returned to live in the water again.
Some believe that the dinosaurs also evolved from a crocodile-like reptile. Many of the dinosaurs, including Baryonyx, Spinosaurus, and Suchomimus (whose name means “crocodile mimic”), have the long, toothy jaws of the crocodiles. Several types of dinosaurs, such as Ceratosaurus, had a tail that would have propelled them through the water easily.
While most scientists don't believe that dinosaurs lived in the water, they do believe that many of them swam very well when they needed to escape predators or wanted to search for food along the shore.
In the Cretaceous period, some of the crocodiles, such as Deinosuchus and Sarcosuchus, were between 40 and 50 feet long! Some experts think that they ate dinosaurs. Do you think they could have eaten a T. rex?
Long after the crocodiles were the survivors in the swamps and rivers all over the rest of the world, the South Pole was home for a salamander the size of a horse. This area wasn't as cold then as it is today, and seemed to be a haven for animals that had disappeared from every other location in the ancient world.
You can hold your own survivor contest by challenging your family or friends to see who can set the fastest time by going through your own survivor course. What kind of obstacles can you make? How about stepping into the middle of several tires, crawling through a bunch of boxes, wading through a pool, and then untying a flag when you reach the end of the course?
Words to Know
A survivor is one who succeeds in lasting a long time. The dinosaurs survived for millions of years on an ever-changing planet.
You're Wrestling What?
The crocodiles of today are a much smaller version of the animal that you would have seen in the time of the dinosaurs. Alligators also belong to the same family as the crocodiles. Alligators have tremendous strength in their jaws, especially when they are snapping them shut, but their trainers know how to use their hands to hold the alligator's mouth closed.
Crocodiles are much larger and more vicious than the alligators. Have you ever watched a show where someone wrestles with an alligator? Can you imagine anyone training or wrestling with the crocodiles? How about their ancestors or their cousin, the dinosaur?
A Rocky Croc
What do you call a dinosaur wearing a blindfold?
If the dinosaurs were still around, someone would probably be trying to train them or at least display them in a cage. Maybe the safest kind of crocodile that you could have would be one that was made out of rock!
If you want to make one, all you need is some glue, a piece of cardboard, and several rocks. You need to pick out three oval-shaped rocks, one of them larger than the other two; six small round rocks; and three pointed ones, one medium-sized and two small. Once you've gathered your rocks, here's how to put your crocodile together:
Who am I?
The only things longer than my front legs were my long neck and tail. My name sounds like the opposite of a front-iosaurus. Who am I?
Lay the largest oval rock down on your piece of cardboard. This rock will be the crocodile's body.
Set the other two oval rocks at one end of the body to make the jaws of the crocodile. To keep the jaws slightly open, place the two small pointed rocks between the jaws, toward the back, and glue them all together.
Tape the jaws till the glue sets, then glue two of the small round rocks on top of the jaw for eyes, and the other four around the body for legs.
Now glue the last pointed rock to the end of the crocodile to make its tail.
When your crocodile is completely dry, you can paint it and add all kinds of decorations.
Can you find the pair of Triceratops skulls that match exactly?