The first dinosaurs had five fingers on each hand, but over time we see a reduction in the number of fingers.

Count the number of fingers in each of these pictures.

Map where you think the reduction from five to four fingers first appeared. Simply click on the cladogram.

Good job! All Theropods show a reduction in the number of fingers.

Click on the next circle on the feature bar to learn about the wishbone.

Oops!

Count the number of fingers carefully.

Click on the place on the cladogram just before you see the first reduction in number.