A newly discovered graveyard of ancient whales in Peru has scientists wondering how on Earth the bus-sized mammals all ended up dying in the same place. "That's the top question," says the director of a nearby museum. Their current location—the middle of a highway under construction on a desert hill—was once a lagoon, scientists say. So maybe an earthquake sealed off dozens of whales there. Or maybe the lagoon dried up. Or perhaps the whales were flung onto shore by a giant wave.
Hard to say—it probably happened 2 million to 7 million years ago. But the find also reveals a fascinating snapshot of ancient sea life, including a dolphin carcass with two walrus-like tusks. "The fossils are exceptionally well preserved and quite complete—a rare combination in paleontology and one that will likely shed light on many facets of the ... ecology and evolution of these extinct species," one paleontologist tells the AP. (For more fossil news, check out one that could be the missing link.)