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The terror birds, which out-competed the mammals in occupying this particular ecological niche, may even have driven mammalian predators to take to the forests instead.

"Our ancestors have chosen an ecological niche where the world is slow enough to make survival possible," the authors write.

In modern ecosystems, that process has led closely related birds of paradise to develop different displays while sharing ecological niches.

"Cichlids are known for filling a huge diversity of different ecological niches and being able to adapt to changes in their environment," they said.

This allows them to inhabit various ecological niches and therefore to engage in less competition with one another.