Some aphid species have unusual and complex reproductive adaptations, while others have fairly simple reproduction.

Compared with other vertebrates, birds have a body plan that shows many unusual adaptations, mostly to facilitate flight.

One fossil preserves an adult with a single large fetus inside of it, indicating that Polycotylus gave live birth, an unusual adaptation among reptiles.

This unusual adaptation is likely a response to the difficulty of finding a mate in their dark and sparsely inhabited deep-sea environment.

Although there are no unusual adaptations in the known material, the animal possesses a combination of characteristics that distinguish it from all other known oryzomyines.

Another unusual adaptation is found in some South American hylids, which brood the eggs on the back of the female.

But even so, there can be unusual adaptations.

An unusual adaptation of the BD-5, the Acapella 100, appeared in the early 1980s.

Turns out the Vulcans have done a lot of scientific studies on them lately because of their unusual reproductive adaptations.

Some species, for instance the recently-discovered E. fengshanense, show unusual adaptations to growing in deep shade in caves.