Coleoid cephalopods, a group encompassing octopuses, squid and cuttlefish, are the most intelligent invertebrates: Octopuses can open jars, squid communicate with their own Morse code and cuttlefish start learning to identify prey when they’re just embryos. In fact, coleoids are the only “animal lineage that has really achieved behavioral sophistication” other than vertebrates, said Joshua Rosenthal, a senior scientist at the Marine Biological Laboratory in Woods Hole, Mass. This sophistication could be related to...

Scientists reviewing video from camera traps watched dumbfounded as a 16-pound badger worked four days to bury a 50-pound calf carcass. Badgers, carnivores native to the American West, are generally nocturnal and spend most of their time in burrows. They are known to cache food to eat later — squirrels and rabbits, typically. No one has ever seen a badger put away such a large hunk of meat....

At the top, two flesh-toned siphons swish water over massive gills. At the bottom, a slimy, eyeless head resembles a mix of wet lips and diseased tonsils. In between, a glistening gunpowder blue body stretches up to four feet long. Instead of eating, bacteria in the creature’s gills helps it suck energy from sulfur. The whole thing is sheathed in a tusklike tube created from its secretions of...