Template:POTD/2012-09-24
The skull of a black rhinoceros (Diceros bicornis), a critically endangered species of rhinoceros native to eastern and central Africa. The two horns on the skull are made of keratin, with the larger front horn typically 50 cm (20 in) long. Sometimes, a third, smaller horn may develop.Photo: Jebulon
 | This picture of the day has been featured on Portal:Mammals. |