After 28-31 days, their wings develop and they are able to leave the nest.

Their wings developed into two powerful arms which end in sharp, rock-hard claws.

Some random neotenous development may have occurred far in the past, so that the bird's wings never developed.

Issidae are small insects generally with a stocky body, as the wings mainly develop in width.

Like those of all penguins, the little penguin's wings have developed into flippers used for swimming.

The wings also develop a brown tinge with age.

At this stage of development, the flapping wings do not develop enough forward thrust for a takeoff roll.

For this reason it is hard to discriminate between the two species during the early stages of their life cycle before the wings have fully developed.

Growth continues, with a whole succession of juvenile stages, at which wings and gonads develop.

He could not fly as a child, and the power only manifested when the wings developed in adolescence.