When continental plates smashed together about 12 million years ago, they didn't just raise new mountains in central Europe—they created the largest lake the world has ever known. This vast body of water—the Paratethys Sea—came to host species found nowhere else, including the world's smallest whales. Two new studies reveal how the ancient body of water took shape and how surrounding changes helped give rise to elephants, giraffes, and other large mammals that wander the planet today.
(...) At its largest, the body of water—which some scientists consider to have been an inland sea—stretched from the eastern Alps into what is now Kazakhstan, covering more than 2.8 million square kilometers. That's an area larger than today's Mediterranean Sea (...) the lake once contained more than 1.77 million cubic kilometers of water, more than 10 times the volume found in all of today's fresh- and saltwater lakes combined.
(...) The Paratethys soon became home to a wide variety of mollusks, crustaceans, and marine mammals found nowhere else on Earth. Many of the whales, dolphins, and seals living there were miniature versions of those found in open seas (...) One species, the 3-meter-long Cetotherium riabinini—1 meter shorter than today's bottlenose dolphin—is the smallest whale ever found in the fossil record. Such dwarfism might have helped these animals adapt to a shrinking Paratethys
(...) The changes to the climate that triggered lake shrinkage also influenced the evolution of land animals (...) the newly exposed shorelines became grasslands—and hot spots for evolution (...) The fossil record shows that in areas north of the Paratethys, the ancestors of modern-day sheep and goats roamed side by side with primitive antelope. And in what is now western Iran, south of the lake, the progenitors of today's giraffes and elephants thrived.
(...) Four lengthy dry periods that occurred between 6.25 million and 8.75 million years ago likely drove those creatures to migrate southwestward into Africa (...)
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