More than 50 million years ago, when the Earth experienced a series of extreme global warming events, early mammals responded by shrinking in size. Dwarfing appears to be a common evolutionary response of some mammals, and the extent of dwarfing seems related to the magnitude of the event.

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More than 50 million years ago, when the Earth experienced a series of extreme global warming events, early mammals responded by shrinking in size. Dwarfing appears to be a common evolutionary response of some mammals, and the extent of dwarfing seems related to the magnitude of the event.