There was a recent discovery of a fossil of a dinosaur that more resembled a bird than any other dinosaur. That got me to thinking what other ways are birds like dinosaurs? Experts argue over facts like whether dinosaurs were hot-blooded or cold-blooded as reptiles would be. Much of the evidence to support this theory is based on fossils of dinosaurs.

Probably the most famous fossil ever found is a small animal with scaly legs, feathers and clawed toes names Archaeopteryx. Dating back about 150 million years, many scientists classify it as a bird while others argue that if you took away the feathers the fossil would be more like other dinosaur fossils that were recovered. On the other hand, Scientists agree that Archaeopteryx clearly couldn't fly, no doubt a very important bird trait. It had a breastbone with no muscles attached for flying unlike birds.

Most paleontologists agree that birds evolved from dinosaurs. They would call birds avian dinosaurs, although birds are actually considered reptiles. A new study has found a particular trait that supports the theory that many dinosaurs, at least the carnivorous ones, had a system of air sacs similar to today's birds. These dinosaurs had hollow sacs in their skeletons which air was pumped into much like birds.

There is other supporting evidence to prove that birds are today's dinosaurs. For one thing, a well preserved small dinosaur was found just over 10 years ago and it was covered in feathers. Other studies show that while grown dinosaurs were covered in scales, baby dinosaurs actually had feathers.

The long standing debate on whether dinosaurs were hot-blooded or cold-blooded plays and important role in their relation to birds. A warm-blooded creature would have the heart and breathing system more similar to a bird than it would say a crocodile. The evidence that supports the fact that they are cold blooded is the fact that their hearts only put out low amounts of oxygen not suitable for flying.

But almost all other evidence shows that there were very much like mammals or birds. For example, recent technology shows four-chambered hearts which more closely resemble birds than other reptiles. The whole superior breathing system and heart system would support a warm-blooded creature as opposed to cold –blooded which rely on the environmental surroundings to regulate body temperature.

All of this evidence cannot prove in complete certainty that dinosaurs were warm-blooded or cold blooded, reptile or mammal. But it does give us something to ponder.