Danielle Tepper had always loved dolphins. When she went on vacation to Hawai'i, she knew she had to see them firsthand. Tepper—now a senior editor at the Humane Society of the United States—wanted to do it ethically, so she avoided captive dolphin attractions. Instead, she booked an excursion to...

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...