The mountain lion known as P-47 survived fires, freeways and hostile ranchers. But in March, the 3-year-old big cat—tracked by California biologists since his kitten days—succumbed to a hidden hazard: an insidious form of food poisoning. Six anticoagulant compounds—chemicals used to kill rodents...

WARNING: This page contains graphic content. When rescuers slowly creaked the rusty door open, the dilapidated building appeared to be empty. Windowless and dark, the sheet-metal structure held no noise, only air thick with spiderwebs, dust and the burning smell of ammonia. Then a head with small...

It seemed like a good idea at the time: Buy a house with a two-acre property, let our energetic herding dog have the run of the place and spend blissful summer days digging side by side in the dirt with her. And it was blissful, watching Mattie carve out her napping spots behind the ferns and tall...