Wall mount of a nandu. A very special object. The nandu (Rhea americana) is a South American ratite from the family Rheidae. A nandu looks much like an ostrich, but is significantly smaller and lighter. An adult nandu is about 90 to 150 cm (8 to 12 inches) long[2] and weighs 20 kg (20 lbs). Other differences from an ostrich are that a nandu has three toes instead of two and that the sexes are hardly distinguishable from each other