Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Dinosaurs are a group of reptiles that appeared during the Mesozoic Era, between 230 and 65 million years ago. They are characterized by their upright stance, with legs located directly beneath the body.
Related terms
Jurassic Period: This is one period within the Mesozoic Era when many well-known dinosaurs lived.
This is when an entire species or group of species dies out, ending its evolutionary lineage. The dinosaurs went extinct at the end of the Cretaceous period.