David Attenborough's Natural Curiosities (2013)

S03E03 Expandable Bodies

Certain animals possess the remarkable ability to alter their size dramatically. The anaconda can consume prey that is twice its length and then survive for over a year without eating again. Meanwhile, a camel's unique hump can nearly double in mass, providing it with the stamina needed to traverse vast desert landscapes. What lies behind the mystery of these adaptable physiques?