Flying back and forth over Cape Cod Bay, a survey plane spotted a half dozen of the world’s rarest creatures: North Atlantic right whales. Such sightings are good news. The species hovers near extinction—by one estimate, fewer than 360 remain. Each time researchers locate a whale, they take pictures...

It was the shot heard around the world. An American trophy hunter shot and severely injured Cecil with an arrow after he was lured outside Hwange National Park in Zimbabwe with elephant carcass bait. About 10 hours later, the hunting party tracked him down. A second arrow ended Cecil’s life. The...