Getting a grip: How some frogs hold on in a torrent of water

Torrent frogs have an amazing ability to climb in wet environments near waterfalls, where ordinary tree frogs would be washed away.

Researchers compared the gripping ability of torrent frogs, a class of frogs that live in fast-flowing mountain or hill streams, to that of tree frogs, and found that torrent frogs were much better at gripping wet, steep and rough surfaces.The frogs' sticky secret, the researchers found, involves hugging wet and rough surfaces with their toes, belly and thighs.

"Torrent frogs adhere to very wet and rough surfaces by attaching not only their specialized toe pads (like many tree frogs do), but also by using their belly and ventral (inner) thigh skin," study researcher Thomas Endlein of the University of Glasgow in Scotland wrote in a statement. [40 Freaky Frog Photos]

Tree frogs can climb smooth surfaces, thanks to capillary forces between the fluid molecules between the wet surfaces and the frogs' toe pads. Yet, puzzlingly, torrent frogs can cling to surfaces even when there's enough water to destroy this adhesive boundary.

Endlein and his colleagues decided to put the amphibians' incredible sticking abilities to the test. They placed a species of torrent frogs (Staurois guttatus) and trees frogs (Rhacophorus pardalis) on a platform that could be tilted from horizontal to upside-down, and tested how long the animals could cling at different angles, levels of roughness and water flow.

On dry, smooth surfaces, both frogs hung on equally well. But on wet surfaces, at both high and low flow rates, the torrent frogs adhered at steeper angles than the tree frogs — even when their toe pads were submerged in water, results showed. 

The rotating platform was transparent, allowing the scientists to measure the areas of the frogs' bodies in contact with the surface.

In addition to their pads, both frog species appeared to use large parts of their bellies and thighs to get a grip. But whereas the tree frogs' bellies and thighs detached from the platform at steeper angles, the torrent frogs increased their use of these body parts.

For Subscribers

FOR SUBSCRIBERSAmerican passenger drafted goodbye texts to her family as Flydubai plane plummeted

FOR SUBSCRIBERSCornell rape allegation pushes embattled New York prosecutor into national spotlight

FOR SUBSCRIBERSAbdul El-Sayed tries to woo MAHA voters as Democrats seek inroads with RFK’s supporters

FOR SUBSCRIBERSKratom-like substances are popping up in a typically benign supplement

FOR SUBSCRIBERSGOP super PAC increases its spending for Sen. Jon Husted in tough Ohio race

FOR SUBSCRIBERSRecords reveal tumultuous marriage between slain New York Times executive and wife

FOR SUBSCRIBERSFrom clean energy warrior to ‘wall of shame,’ James Talarico reverses on a fossil fuel money pledge

FOR SUBSCRIBERSCongressional staff planned official trip with luxury stops in Italy and France weeks before election

FOR SUBSCRIBERSA harrowing ordeal aboard an Israel-bound plane

FOR SUBSCRIBERSOpenAI CEO Sam Altman to skip congressional hearing on rogue AI agents

FOR SUBSCRIBERSKey DOJ lawyers departed Trump ‘grand conspiracy’ probe amid pressure to produce, source says

FOR SUBSCRIBERSTrump’s new AI chatbot often links to a site launched under Clinton 26 years ago

FOR SUBSCRIBERSAt MAHA summit, industry CEOs the movement once vilified take the stage

FOR SUBSCRIBERSThis Paralympian has two goals: Win medals and give away $500,000 to her teammates

FOR SUBSCRIBERSCornell rape allegation spotlights stringent New York state laws that have long drawn criticism

For Subscribers

FOR SUBSCRIBERSAmerican passenger drafted goodbye texts to her family as Flydubai plane plummeted

FOR SUBSCRIBERSCornell rape allegation pushes embattled New York prosecutor into national spotlight

FOR SUBSCRIBERSAbdul El-Sayed tries to woo MAHA voters as Democrats seek inroads with RFK’s supporters

FOR SUBSCRIBERSKratom-like substances are popping up in a typically benign supplement

FOR SUBSCRIBERSGOP super PAC increases its spending for Sen. Jon Husted in tough Ohio race

FOR SUBSCRIBERSRecords reveal tumultuous marriage between slain New York Times executive and wife

FOR SUBSCRIBERSFrom clean energy warrior to ‘wall of shame,’ James Talarico reverses on a fossil fuel money pledge

FOR SUBSCRIBERSCongressional staff planned official trip with luxury stops in Italy and France weeks before election

FOR SUBSCRIBERSA harrowing ordeal aboard an Israel-bound plane

FOR SUBSCRIBERSOpenAI CEO Sam Altman to skip congressional hearing on rogue AI agents

FOR SUBSCRIBERSKey DOJ lawyers departed Trump ‘grand conspiracy’ probe amid pressure to produce, source says

FOR SUBSCRIBERSTrump’s new AI chatbot often links to a site launched under Clinton 26 years ago

FOR SUBSCRIBERSAt MAHA summit, industry CEOs the movement once vilified take the stage

FOR SUBSCRIBERSThis Paralympian has two goals: Win medals and give away $500,000 to her teammates

FOR SUBSCRIBERSCornell rape allegation spotlights stringent New York state laws that have long drawn criticism

Measurements from a force transducer showed the forces on different skin parts weakened in wet conditions by nearly the same amount in both types of frog, suggesting the torrent frogs' better grip was due to the greater body area in contact with the surface.

Using a scanning electron microscope, the researchers also found that the toe pads of torrent frogs are equipped with elongated cells on their edges, with straight channels in between. These channels could allow excess water to drain away, helping the frogs keep their grip.

The study was detailed Wednesday in the journal PLOS ONE.

Follow Tanya Lewis on Twitter and Google+. Follow us @livescience, Facebook and Google+. Original article on LiveScience.

• Creative Creatures: 10 Animals That Use Tools
• Beastly Academy Awards: Stars of the Animal Kingdom
• Album: Bizarre Frogs, Lizards and Salamanders