Smarter Balanced
Classifying Vertebrates
What features do scientists use to classify animals into groups? Class groups examine a series of paired images of vertebrates (a bass and a trout, a toad and a newt, a crocodile and a tortoise, an owl and a robin, a tiger and a bear)...
PBS
Pbs Nova: Crocodiles!
This PBS Nova site lists a table of contents on subjects involving the Crocodile. How did they outlive the dinosaurs? What makes them tick? What are the different types of crocodiles?