Researchers say the Tuatara, a reptile from New Zealand, chews its food by slicing it like a knife. The greenish-brown reptiles can grow up to 31 inches and eat beetles, spiders, crickets, small lizards and, occasionally, sea birds. Dr. Marc Jones, from the University College London Cell and Developmental Biology department, with colleagues from the University of Hull, developed a computer model to demonstrate how the tuatara is able to slice its food. When the reptile chews, the lower jaw closes between two rows of upper teeth. Once closed, the lower jaw slides forward a few millimeters to cut food between sharp edges on the teeth, slicing food apart like a knife.