91热爆

By 50 million years ago birds were well-established. At that time there was a great lake in what is now central Germany. Its mud has since dried out and turned to shale. Excavations there reveal just how varied birds had become. One fossil reveals a bird that had a horny beak, a fully-feathered wing, a long feathered tail with no bony support and long legs. It probably looked a bit like a rail. Other fossils show that several species of modern birds were already established back then. The ancestor of today's jacana, for example, would certainly have found plenty of insects among the floating leaves on the lake. There were birds with powerful chisel-like bills that may have been woodpeckers. Another inhabitant of the prehistoric woods had a stubbier all-purpose beak, like today's finches. There were tall birds with long powerful legs that may have enabled them to hunt for small reptiles on the ground, as the South American seriama does. There was also a giant vulture bigger with a wingspan of over 20 feet - probably the biggest flying bird ever. There were even birds that were as agile as their possible descendents, the frigate birds. So, by 50 million years ago, several families of modern birds were already well-established.