Animals see with two kinds of cells on their retina, both named according to shape. "Rods" are sensitive and work well in low light but only detect general shapes in black, white and gray. "Cones" require more light to function but distinguish details in color. Birds of prey that are active during the day have densely packed cone cells, allowing them to see details from a distance. Most nocturnal animals have few or no cone cells but lots of rods. This abundance of light-catching cells plus a reflecting layer of tissue (called the tapetum lucidum) allows owls, coyotes and bobcats to see well at night.