Young Male Vervet monkey (Chlorocebus pygerythrus) sitting on grass and chewing on cattail shoot. Studies have shown that primates can also do self-medication. Chewing on cattail stems not only provides essential nutrients such as beta carotene, niacin, riboflavin, thiamin, potassium, phosphorus, and vitamin C but cattail is also known for its medicinal properties as an anti-septic and anti-inflammatory agent, in particular against intestinal disorders. Captured at the Kiligolf estate, near Usa river, Tanzania.