They seem so different, but birds actually ARE dinosaurs. We know this partially because there are dinosaurs whose skeletons look almost exactly like birds (hollow bones, similar hips, similar hands (modified as wings in birds, but same skeletal structure) and feet (same 3 toes with a fourth shrunken and moved up the back of the leg). In fact, we have fossils of small dinosaurs that actually had feathers (Archaeopteryx)!

We don't know if dinos that are closely related to birds were warm-blooded, but lots of people think they were, especially since we know they had feathers.

So, it actually isn't correct when people say that dinosaurs are extinct, because birds are living dinosaurs just like humans are living primates.

Birds are dinosaurs. Dinosaurs have an open hole through their hips where the upper leg bone attaches to the pelvic girdle. They also have ankle morphology that stabilizes their feet and gives them a spring-like nature, enabling them to run very quickly (but not turn easily while on the ground). Since dinosaurs are reptiles, they have all of the other characteristics that reptiles generally do (e.g. four-color vision).

Actually, birds are dinosaurs. Birds are living representatives of the dinosaur group Saurischians meaning those birds and more typical dinosaurs like T. Rex share a common ancestor. Birds are more closely related to T. Rex than they are to bats (a mammal)! Because of this, they share a lot of characteristics with T. Rex and other dinosaurs. Some similar characteristics are: skull structure, hip bone structure, and the fact that they walk on two legs.