From ScienceAlert.com…
Tens of million years ago, sand tiger sharks hunted in the waters off the Antarctic Peninsula, gliding over a thriving marine ecosystem on the seafloor below.
All that remains of them today is their sharp pointed teeth, but those teeth tell a story.
They’re helping solve the mystery of why the Earth, some 50 million years ago, began shifting from a “greenhouse” climate that was warmer than today toward cooler “icehouse” conditions.
Many theories about this climate shift focus on Antarctica. There is geologic evidence that both the Drake Passage, which is the water between South America and the Antarctic Peninsula, and the Tasman Gateway, between Australia and East Antarctica, widened and deepened during this time as Earth’s tectonic plates moved.
