Australia: The Land Where Time Began |
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Giant Flightless Birds After the mass extinction at the end of the Cretaceous when the last of the dinosaurs, other than those that had crossed the line into birds, died out they weren't replaced immediately by the mammals that had been held in check by the dominance of the dinosaurs. There was, in fact, a period of time, from the start of the Palaeocene to some time in the Eocene, when the dinosaurs were replaced by giant flightless birds. It is believed, based on biomechanical studies, that at least some of them were carnivores, so it would seem the dinosaurs had never really left the scene, only now they were covered in feathers and had crossed the line from reptile to bird. The remains of these birds, more then 2 m tall, such as the Diatryma (Gastornis), have been found in North America and Europe, New Zealand, Madagascar, and Australia. At this time Australia had its own variety of giant flightless birds, the Dromornithids. A study published in the journal Systematic Biology has found that all the living, and recently extinct, flightless birds, probably descended from ground feeding flighted birds. When the level of predation dropped with the extinction of the dinosaurs they increased in size and weight to the point where they could no longer fly.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |