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Controlling blood flow to their toes may help the amphibians stick to, and unstick from, their surroundings

Animals come with all kinds of things at the ends of their toes: nails, claws, talons. But the Aneides genus of salamander has them beat with translucent toes that inflate with blood.

The amphibians might be adjusting their toe shape, the researchers propose. Higher blood flow could inflate the toe, like a soccer ball, reducing its contact with the ground and making it easier to unstick. (The video above shows an engorging toe’s surface expand by 5%.) Lower blood flow could do the opposite, flattening the sticky toe against surfaces when hanging on for dear life. The team also showed the salamanders may fill and drain each side of their toes independently, providing fine-tuned toe shape adjustments.

It costs energy, and skin, to repeatedly peel an adhesive toe off of tree trunks and branches. But slipping is even worse. Salamanders’ inflatable digits may solve both problems.