How Pandas Survive Solely on Bamboo - Evolutionary History

An ancient fossil reveals the earliest panda to survive solely on bamboo and the evolutionary history of panda’s false thumbs.

When is a thumb not a thumb? When it is an elongated wrist bone of the giant panda used to grasp bamboo. Through its long evolutionary history, the panda’s hand has never developed a truly opposable thumb and instead evolved a thumb like digit from a wrist bone, the radial sesamoid. This unique adaptation helps these bears subsist entirely on bamboo despite being bears (members of the order carnivora, or meat-eaters). In a new paper published in Scientific Reports, the Natural History Museum of Los Angeles County’s Curator of Vertebrate Paleontology Xiaoming Wang and colleagues report on the discovery of the earliest bamboo-eating ancestral panda to have this ‘thumb.’ Surprisingly, it is longer than its modern descendants.