Gorillas (IMAGE) Harvard University Caption Grauer's gorilla specimens at the Royal Museum for Central Africa in Tervuren (Belgium), showing typical dental calculus deposits on the teeth that are stained dark likely as a result of their herbivorous diet. Credit Katerina Guschanski Usage Restrictions CC-By License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.