While working on her PhD in 1992, Karen Lips went to Las Tablas, Panama, to study the biology of a tree frog, Hyla calypso, an inch-long, spiny, bright-green creature. As she walked through transects in the forest, measuring and sexing frog individuals, here and there she noticed a handful of dead frogs on the forest floor. Collecting them, but not thinking much of it, she took the dead frogs to a veterinarian. The vet examined the frogs and noticed something strange on their skin, but could not explain their deaths.
When Lips returned to Las Tablas two years later, she couldn't find any frogs. Soon after, Lips found 50 dead frogs at another collection site, Fortuna, further east in Panama. "As soon as I got there I could see things weren't quite right," Lips...