'Skydiving' salamanders can fully control blood flow in their toes

Wandering salamanders, also known as “skydiving salamanders,” have fascinated scientists for years with their ability to jump and glide effortlessly through the towering canopies of coastal redwood forests.

Despite their small size, these amphibians navigate high-altitude branches with precision, sticking their landings and taking off with ease.

Until recently, the mechanics behind their remarkable acrobatic movement remained a mystery. Now, a new study reveals a surprising answer: blood-powered toes.

Salamanders that control blood flow

Researchers at Washington State University discovered that wandering salamanders (Aneides vagrans) can rapidly control the blood flow in their toe tips.

This ability allows them to grip, detach, and move through their arboreal environment with remarkable efficiency.

The study not only sheds light on an unknown aspect of salamander physiology but also has potential implications for technological advances in adhesives, prosthetics, and robotic limbs.

The research team found that salamanders can fill, trap, and drain blood within their toe tips.

This process helps them fine-tune their attachment and detachment from surfaces, providing the grip necessary for climbing and the release required for efficient movement.

The discovery challenges previous assumptions about the function of the visible red “lakes” of blood in their translucent toes. These structures were long thought to aid in oxygenation, but no scientific evidence supported that claim.

Advantages of the control

The study suggests that controlling blood flow in the toes allows salamanders to adjust pressure asymmetrically.

This fine-tuned control helps them navigate the irregular surfaces of tree bark. Surprisingly, the blood influx before “toe-off” does not aid in attachment but rather helps the salamanders detach.

By slightly inflating their toe tips, they reduce the surface area in contact with the bark, minimizing the energy required to let go. This efficiency is crucial when gliding between branches and ensuring safe landings.

“Gecko-inspired adhesives already allow surfaces to be reused without losing stickiness,” said Christian Brown, lead author of the study, and a postdoctoral researcher in integrative physiology and neuroscience at Washington State University.

“Understanding salamander toes could lead to similar breakthroughs in attachment technologies.”

A documentary shoot

The origins of this study trace back to an unexpected moment during the filming of the documentary The Americas, which will air on February 23, 2025 on NBC and Peacock.

Brown was assisting on set as a salamander expert when he noticed something unusual through the production team’s high-powered camera lenses.

Just before a wandering salamander took a step, blood appeared to rush into its toe tips. Brown and camera assistant William Goldenberg observed this phenomenon multiple times.

The repeated occurrence caught their attention. “We looked at each other like, ‘Did you see that?’” Brown related.

Although the documentary team moved on to other subjects, Brown’s curiosity lingered. After filming wrapped, he reached out to Goldenberg and proposed an experiment.

Using high-resolution film equipment, they would investigate whether salamanders consistently displayed this blood-powered toe mechanism under controlled conditions.

Salamanders regulating their blood flow

The research team conducted detailed video trials and microscopic analysis at Washington State University’s Franceschi Microscopy & Imaging Center.

Their findings confirmed that wandering salamanders regulate blood flow to each individual toe tip, which allows them to modify grip strength as needed.

This discovery provides insight into how salamanders navigate the complex terrain of the redwood canopy. The ability to release their grip efficiently is particularly significant.

“If you’re climbing a redwood and have 18 toes gripping bark, being able to detach efficiently without damaging your toe tips makes a huge difference,” Brown said.

The research suggests that this mechanism plays a crucial role in the salamanders’ ability to thrive in the towering heights of their natural habitat.

Implications beyond one species

While this study focused on Aneides vagrans, the findings could have broader implications. Other salamander species, including aquatic ones, also have vascularized toe structures.

These structures may serve different purposes depending on the environment, from regulating grip on wet surfaces to enhancing movement across diverse landscapes.

The discovery could also inspire innovations beyond biology. Scientists studying bioinspired design are particularly interested in nature’s solutions to movement and adhesion problems.

By understanding how salamanders control their grip with blood-powered toe tips, researchers may be able to develop new adhesives and prosthetics that mimic this ability.

Brown and his colleagues plan to expand their research to investigate how similar mechanisms function in other salamander species.

“This could redefine our understanding of how salamanders move across diverse habitats,” Brown said. The findings could help explain how different species adapt to their environments and refine our knowledge of biomechanics in amphibians.

New perspective on salamander movement

The discovery of blood-powered toes in wandering salamanders challenges previous assumptions about their movement and grip strength.

As scientists continue to study these remarkable amphibians, they may uncover even more secrets hidden within their physiology.

For now, the ability of wandering salamanders to control their grip with precision remains an intriguing discovery in animal biomechanics.

The study is published in the Journal of Morphology.

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