On a spring day, Ithaca, New York–based photographer Melissa Groo watched a mother gray squirrel painstakingly move her kits to a new nest. “Grasping them in her mouth,” Groo said, the mother carried each baby “along a vast network of branches to a cavity in a tree on the other side of the yard. Just before she arrived at the new home, she would brace herself and make a death-defying leap across 8 feet of air… After successfully stuffing each youngster into the new home, she would collapse on a branch, often with her limbs dangling. This move to a new den was obviously very taxing!”