Select the one animal that has all of the reptile traits listed above.
Cardinalfish have scaly skin and live near coral reefs. Cardinalfish lay eggs with no shells and have fins that help them swim underwater. American crocodiles often live where rivers flow into the ocean. In these places, the fresh water and salt water mix. This mixing creates the somewhat salty, or brackish, water that these crocodiles prefer. American crocodiles have scaly, waterproof skin and hatch from eggs with shells.
Reptiles are a group of animals with similar traits. The following traits can be used to identify reptiles:
They have scaly, waterproof skin.
They make eggs with shells. Observe the animals and read the descriptions.
Scientists sort animals with similar traits into groups. This is called classification. Classification helps scientists learn about how animals live.
How do scientists classify animals? First, they make observations about an animal. Scientists observe the animal's traits, including its body parts and behavior. Then, scientists compare the animal's traits to other animals' traits. Scientists classify animals with similar traits into a group.
To decide if an animal is part of a group, look at the traits of the group.
Reptiles have the following traits:
They have scaly, waterproof skin.
They make eggs with shells.
Compare each animal's traits to the group's traits. Select the animal with traits similar to the group's traits.
An American crocodile has the following traits:
It has scaly, waterproof skin.
It makes eggs with shells.
An American crocodile has the traits of a reptile. An American crocodile is a reptile.
A cardinalfish has the following traits:
It has fins, not limbs.
It makes eggs with no shells.
A cardinalfish does not have all of the traits of a reptile. A cardinalfish is a fish.