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Scientists discover a giant 66-pound rodent that lived 34 million years ago

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PaleontologyMammalian evolution

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Scientists have discovered fossils of Yakamys sirindhornae, a giant rodent species that lived in Thailand approximately 34 million years ago and weighed around 66 pounds. This finding pushes back the timeline for when enormous rodents evolved, as this specimen was roughly twice the size of other known rodents from the same period. The discovery provides new insights into the evolutionary history and diversification of large-bodied rodents.


This discovery revises our understanding of rodent evolution and demonstrates that gigantism in rodents appeared earlier in the fossil record than scientists previously believed. The finding contributes to knowledge about mammalian body size evolution and paleoenvironmental conditions in Southeast Asia during the Eocene-Oligocene period.


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Scientists have uncovered fossils of a giant rodent that lived in Thailand 34 million years ago, revealing that enormous rodents evolved much earlier than previously thought. Named Yakamys sirindhornae, the ancient animal may have weighed around 66 pounds, roughly twice as much as other known rodents of its time.

Source: Scientists discover a giant 66-pound rodent that lived 34 million years ago