NIGEL MARSH/SEAPICS.COM

FEELING BLUE: A bobtail squid in the Indian Ocean turns blue.

Octopus, squid, and cuttlefish have special skin that allows them to change color to blend in, stand out, and even communicate. But scientists say these cephalopods may not have developed this ability alone. Recently, scientists studied the origins of a protein—a large biological molecule—called reflectin that’s responsible for the animals’ color-changing ability. They think bacteria living in ancient cephalopods transferred their reflectin-making genes, units of hereditary information, to their hosts. “Such gene transfers can change species’ characteristics over long periods of evolution,” says biologist Can Xie, who worked on the study at Peking University in China.