The African openbill (Anastomus lamelligerus) is a species of stork from the family Ciconiidae. It is widely distributed in Sub-Saharan Africa and western regions of Madagascar. This species is considered common to locally abundant across its range, although it has a patchy distribution. Some experts consider there to be two sub-species, A. l. lamelligerus distributed on the continent and A. l. madagascariensis living on the island of Madagascar. Scientists distinguish between the two sub-species due to the more pronounced longitudinal ridges on the bills of adult A. l. madagascariensis. The Asian openbill (Anastomus oscitans) found in Asia is the African openbill’s closest relative. The two species share the same notably large bill of a peculiar shape that gives them their name. Description The African openbill is a stork measuring 80-94 cm and weighing 1-1.3 kg. The species does not exhibit any major sexual dimorphism, although the males are slightly larger than the females and have a longer and heavier bill. The adult bill is between 135-196 mm in length, brownish in color and has a gap between the upper and lower mandible. This gap is non-existent in juvenile birds and develops as the bird ages. It is because the two mandibles of the beak only meet at the tip and not in the middle that this stork genus received the name of “openbill”. The adult plumage is overall black with iridescent green feathers on their backs, coverts and abdomens. The juvenile plumage is usually less vibrant and browner in color with the feathers of the underparts having pale tips. The legs and feet are black. The eyes are grey with grey lores and no distinct coloration of the eye-ring. Bill shape The gap in the bill of the African Openbill stork was first hypothesized to serve as a nutcracker, crushing the shells of the snails this stork feeds on. Scientists later demonstrated that the bill does not serve this function. Rather the opening between the two mandibles facilitates grasping the shells of the snails. The convergent tips of the mandibles prevent the slipping forward of a spherical object being carried by the storks. The curve in the lower mandible allows the stork to have the perfect angle of attack to force its way under the operculum and release the molluscs from their shells. The bill of the African openbill storks closely evolved with the bird’s specialized diet, allowing for the