The closest living relatives of the extinct dinosaurs might be singing right outside your window. Birds are direct descendants of the dinosaurs. In fact, birds technically ARE dinosaurs.

You can see a family tree at:
dinosaurs .

When you look at this tree (which is called a cladogram), you will see that birds are most closely related to the group that contains T. rex. This page also shows a side-by-side comparison of T. rex and Chicken skeletons. What are some things that T. rex had in common with birds? What is different?

No non-bird dinosaurs flew, but there was a vertebrate (animal with a backbone and skull) that was flying around over the non-bird dinosaurs. It was the pterosaur. It did not have feathers. It used a thin sheet of skin that stretched out from its body and attached to its arm, hand, and one very long finger. The most similar wing around today is on mammals. Bats have a normal-size thumb, but the rest of their fingers are very long and support a thin skin. Having the wing attached to 4 fingers gives bats incredible control. This site shows a comparison between bat, bird, and pterosaur wings:

site here .

The picture doesn’t show how BIG pterosaurs were. I took a vertebrate paleontology course once and we got to go to the basement of the Museum of the Rockies. (Museums only have room to display a small fraction of what they have, so their storage areas are full of treasures.) The wing of the pterosaur was so long that it took three of us to hold the bones of one. Can you imagine looking up and seeing a predator the size of an airplane flying overhead? The pterosaurs and non-bird dinosaurs were extinct 65 million years ago, though, long before humans existed.

Why are all the wing structures so different? The pterosaurs, bats, and birds all evolved their wings independently. They do not share an ancestor that had wings. On the other hand (there’s a bad pun in there), all birds apparently share one common ancestor that had wings. The birds use their wings in different ways, so they have different shapes, but they share the same general structure. All have feathers too. Feathers are what makes a bird a bird.

I hope you will get a chance to go outside and watch your local dinosaurs this weekend.

Interesting question! To answer it we must first remind ourselves that birds ARE a kind of dinosaur. The fossil record has pretty much proven that. The closest LIVING relatives of dinosaurs are crocodiles. Collectively, dinosaurs plus crocodiles are called archosaurs. There are various extinct archosaurs that are closer relatives of dinosaurs than crocodiles, including: pterosaurs, silesaurs, and Marasuchus.

Birds are the great great great [and lots more 'greats'] grandchildren of dinosaurs.

This is a cool article about the idea that birds are related to dinosaurs and how it was proved:
Dinosaurs' Living Descendants | Science | Smithsonian
dinosaurs living descendants

Here's a link from ScienceLine:
How many species related to dinosaurs are left here

The closest living relative to dinosaurs that are not dinosaurs themselves are the crocodilians (crocodiles, alligators, etc.). Pterosaurs are more closely related to dinosaurs, but are extinct. Birds of course are living dinosaurs.