Galapagos tortoises’ shells are not solid: Although their huge shells look like a vast weight for the animals to carry, the shells are actually made up of honeycomb-like structures with air filled holes.

This means that the shells are not as heavy as they look, and allow the tortoises to move about without much difficulty.

The top part of the shell is called the carapace; the belly of the shell is known as the plastron.