Red flanked Duiker is a species of duiker, also known as Diving Buck for its dexterity in diving. The Red flanked Duiker is a tiny, stocky duiker with a rounded back. They are classified in the family Bovidae and the subfamily Cephalophinae. Red-flanked duikers, called Èsúró in Yoruba, grow to almost 35 cm in height and weigh up to 12 kg. They have russet coats, with black legs and backs, and white underbellies. Shape is perfectly suited for diving for cover in the forest.
In Nigeria, it occurs as subspecies R. r. rufilatus in the Guinea Savannas and some Sudan savannas. Red-flanked duikers inhabit more open country than other forest duikers, thus are more frequently seen. Population is probably declining because of overhunting and habit modification. They browse on leaves, fruits, shoots, buds seeds, small birds, rodents, insects and carrion, mostly during the early morning and late evening. The Red-flanked Duiker lives singly or in pairs and is very sedentary. Gestation of 245 days culminates in the birth of a litter of one young, weaned after 3 months, sexually mature, if female, by 18 months and which may live for up to 15 years.