I am going to skip over the arguments against the imbeciles who believe that the world is 6000 years old. Richard Dawkins are nobly taking that task upon himself.
About 150 million years ago, the pterodactyl roamed the skies (pterodaktulos, meaning “winged finger”). There is something about that shape (and size!) that seems to still take hold of human imagination and fear; imagine the shadow crossing your path. Though they were not excellent fliers, it must have been pretty useful for a carnivore reptile.
Then, the paleobiologists got wildly excited when they found various fossils of what is seen as a transitional creature; half bird, half reptile. The gorgeous Archaeopteryx “original bird” or “first bird”). Teeth, claws, wings, reptile tail. It is pretty much more reptile than bird. A reptile with feathers.
So, as the theory go, the flying reptiles changed into birds and lost the obvious reptilian traits. But evolution is a wonderful thing. In the swamps of South America lives a bird called Hoatzin (Opisthocomus hoazin).
Though it is definitely a bird as we know them, (and the adult is one of the coolest-looking birds!) The chicks have a curious trait: they have claws on their wings like the pterodactyl and the archaeopteryx . Living above water, the chicks sometimes fall in, and to be able to get back up, it uses those extra claws. They retract as the chick grows older and are capable of flying. The taxonomic placement of this brilliant species are greatly debated, and it is odd in several aspects: it is purely herbivore, and its digestive system are close to bovine as it uses bacterial fermentation to digest plant material.
But no contest: the coolest thing about it is the chicks claws.