Flightless bird that require a significant amount of overall metabolic energy, ratites decrease their basal metabolic rate and conserve energy. A study looking at the basal rates of birds found a significant correlation between low basal rate and pectoral muscle mass in kiwis. On the contrary, flightless penguins exude an intermediate basal rate. This is likely because penguins have well-developed pectoral muscles for hunting and diving in the water. For ground feeding birds, a cursorial lifestyle is more economical and allows for easier access to dietary requirements. Flying birds have different wing and feather structures that make flying easier, while flightless birds'
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