According to the fossil record, cetaceans—whales, dolphins and their relatives—evolved from four-legged land mammals that returned to the oceans beginning some 50 million years ago. Today, their descendants are threatened by a different land-based mammal that has also returned to the sea: humans. According to the fossil record, cetaceans—whales, dolphins and their relatives—evolved from four-legged land mammals that returned to the oceans beginning some 50 million years ago. Today, their descendants are threatened by a different land-based mammal that has also returned to the sea: humans. Ecology Phys.org – latest science and technology news stories
Fewer than 7% of global hotspots for whale-ship collisions have protection measures in place, researchers report
