Martens are fuzzy and cute-faced—they’re probably the most adorable members of the weasel family—but you sure wouldn’t want to run into one in a dark alley. At least, not if you’re a mouse. Martens are fierce predators, with sharp, semi-retractable claws and lightning reflexes.
The claws aren’t just for slicing and dicing: bushy-tailed, cat-sized martens are excellent climbers. They can silently scale tree trunks to sneak up on squirrels or to steal eggs from birds’ nests, though they prefer to catch most of their meals—including voles, ruffed grouse, birds, and hares—on the ground.
Martens are solitary, except during the summer breeding season. But even though a female mates in July, her fertilized eggs won’t start developing, and she won’t become pregnant, until the winter. This delayed implantation (“embryonic diapause”) also happens in marsupials, rodents, and other weasels.