If it were not for the hollow bones the 30-ton creature would have required inordinate amounts of energy, and thus more food, to move around.

They had very long limbs, hollow bones, and large brains and eyes.

To do this, birds use wings with light, hollow bones and feathers on them.

"He must have hollow bones or something," Robin said.

Bone marrow is a type of tissue that can be found in hollow bones.

Most birds have hollow main bones with air sacs in them.

Like most modern birds and other theropods, it had hollow bones.

The mass equation just wouldn't work, even taking hollow bones into account.

The radiation had made his bones brittle as well as hollow.

They have small black beady eyes and are quite light for their size due to their hollow bones.