The African crested rat (Lophiomys imhausi) has a broad, white-bordered strip of hairs covering an area of glandular skin on the flank.  When the animal is threatened or excited, the mane on its back erects and this flank strip parts, exposing the glandular area. The hairs in this flank area are highly specialised; at the tips they are like ordinary hairs, but are otherwise spongy, fibrous, and absorbent. The rat is known to deliberately chew the roots and bark of the Poison-arrow tree (Acokanthera schimperi), which contains ouabain.  After the rat has chewed the tree, instead of swallowing the poison it slathers the resulting masticate onto its specialised flank hairs which are adapted to absorb the poisonous mixture.  It thereby creates a defense mechanism that can sicken or even kill predators which attempt to bite it.