We investigated whether the food quality of tree foliage for African savanna browsers varies across the feeding height range of the guild. This was to address the question of why giraffes (Giraffa camelopardalis) generally feed at a higher level in the canopy than is accessible to all other browsers. We defined a giraffe browse unit (GBU) as the length of twig corresponding to the average “bite” taken by giraffes from two staple browse plants: Acacia nigrescens and Boscia albitrunca. We