Flightless bird requirement for flightlessness. The kiwi does not exhibit gigantism, along with tinamous, even though they coexisted with the moa and rhea that both exhibit gigantism. This could be the result of different ancestral flighted birds arrival or because of competitive exclusion. The first flightless bird to arrive in each environment utilized the large flightless herbivore or omnivore niche, forcing the later arrivals to remain smaller. In environments where flightless birds are not present, it is possible that after the K/T Boundary there were no niches for them to fill. They were pushed out by other herbivorous mammals. New Zealand had
Flightless dung beetle Flightless dung beetle The flightless dung beetle ("Circellium bacchus") is a species of dung beetle endemic to a few areas of South Africa, including the Addo Elephant National Park and the Buffalo Valley Game Farm. It is the only species in the genus Circellium. The loss of flight allows the beetle to use the empty space below the elytra as a carbon dioxide storage tank, creating a unique breathing mechanism which conserves water, a valuable survival trait in the arid regions it lives in. The species was originally widespread in Southern Africa, but it only survives in the few areas