Native to China's Yangtze River, these fish grew 23 feet in length, but haven't been spotted since 2003. From a report: The Chinese paddlefish and its close relatives have been around for at least 200 million years. The species, reaching up to 23 feet in length, survived unimaginable changes and upheavals, such as the mass extinction that killed the dinosaurs and marine reptiles like plesiosaurs that it swam alongside. In its time, flowering plants evolved, and came to populate the shores of its ancestral home, the Yangtze River, in modern-day China. Much later, bamboo came on the scene, and well after that, giant pandas. In the last few thousand years, a blink in evolutionary time, the land filled with people, and China became the most populous country on Earth. In the muddy waters of the Yangtze, the paddlefish lived as it had for eons, using its special sword-like snout to sense electrical activity to find prey, such as crustaceans and fish. But there's one phenomenon this ancient species, sometimes called the "panda of the Yangtze," could not survive -- humans. A new paper published in the Science of the Total Environment concludes that the species has gone extinct, mainly due to overfishing and dam construction. It's "a reprehensible and an irreparable loss," says study leader Qiwei Wei of the Chinese Academy of Fishery Sciences, who's been looking for the animal for decades.

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