Crocodiles can't fly. Birds can. Scientists have finally figured out why

TL;DR: birds have wings

Crocodiles prefer light rail and/or bus lines for short trips, and high speed rail for longer voyages. Everyone knows that.

Even if crocodiles somehow had wings, the metabolic difference in power alone would mean they could never fly.

How did birds and crocodiles become so different? The conventional assumption has been that their common ancestor was more like a crocodile than a bird—but our new research shows the opposite is most likely the truth.

Scientists thought warm-bloodedness had appeared only in the dinosaur-bird lineage.

living crocodiles have four-chambered hearts. The only other groups with such hearts are warm-blooded birds and mammals, and there is a functional connection with warm-bloodedness.

modern crocodiles have a warm-blooded-style heart but produce the low blood-flow rates and pressures we would expect for their cold-blooded nature. This suggests their hearts once evolved for warm-blooded life.

Reversion to a cold-blooded metabolism may have saved the crocodile lineage from extinction 66 million years ago, when an asteroid ended most dinosaur lineages, except, of course, the birds.

Crocks are heavy, dense lizards without wings, adapted to stalk semi-aquatic environments, whereas birds have wings and are light?