The "Big Five" refers to five iconic African mammals (Rhinoceros, Elephant, Buffalo, Lion and Leopard), and has long been used to popularize safari destinations in Southern and East Africa. Many might be unaware of the fact that this is an old hunting term - these five animals were singled out because they are considered the most risky of all African animals to hunt. Furthermore the Rhino included in this list is the Black Rhino; a species infamous for its cantankerous nature and unwavering charge. The critically endangered Eastern Black Rhino (Diceros bicornis michaeli), the rarest of all the Black Rhino subspecies, is best viewed within the Ngorongoro Crater of Tanzania. The steep crater rim and open grassland of the floor have created an area that is relatively easy to police, resulting in one of the few remaining strongholds for this relentlessly poached animal. This exciting image taken by Cuan Rush shows two identification notches in the animal's right ear, a clear sign that this coveted animal is identified and more importantly - closely monitored!

We hope that the "Big Five" catch phrase is kept complete with the survival of this fantastic mammal long into the future, and that this East African subspecies continues to patrol its crater home. Join Fraser Gear on tour for Indri on a journey through Tanzania in May 2010, as we explore Ngorongoro and other famous game reserves during one of our finest ultimate mammal voyages!