An order of placental mammals, including bats and flying foxes, with the forelimbs modified for flight or gliding: Female cheiropters have placentas which are temporary organs that join the mothers and their fetuses, or unborn babies, and which transfer oxygen and nutrients from the mother and even to provide for the release of carbon dioxide and waste products from the fetuses.

It is said that cheiropters are the only mammals that, with their large membranous wings, were able to achieve active or powered flight, thus making the atmosphere an additional habitat for them.