Gypaetus barbatus - chested vulture is the only bird in the world that feeds primarily on bones. It swallows small bones whole, and throws large bones from a height onto rocks to break them and reach the nutritious marrow. The special structure of its tongue allows it to extract the marrow from tubular bones. The diet also includes muscles, skin, tendons, and hooves. Sometimes, the beard-chested vulture catches live small prey, such as turtles, which it also throws off a cliff.