After years of scientific studies taking place across the animal kingdom, you would think that we'd have most of it covered. With the incredible advances in camera technology, we've even started to see the most obscure and strange elements of mother nature from the comforts of our own homes, thanks to the likes of David Attenborough and the crew of documentaries like Planet Earth and Life.
However, there are still a few mysteries to solve. For instance - geckos have been observed running across the surface of water, a feat unseen in any other animals their size, but it's only now that we've got a clue how they were managing it.
Geckos are known for walking on walls, and in some cases even gliding through the air, but their ability to run on water is a relatively recent discovery. This feat has been documented in other animals, such as the basilisk lizard (which runs on its back legs across water) or smaller creatures such as spiders, which rely on their surface tension to keep afloat.
This skill hadn't been observed in mid-sized creatures, who neither have the small size nor the strength to prevent falling into the water - until footage emerged of one particular gecko. Dr. Ardian Jusufi captured footage on his phone of a flat-tailed house gecko, running across a flooded area of Singapore. After seeing this footage, a former colleague of Jusufi's, Dr Jasmine Nirody, sought to find out more.
The University of Oxford biophysicist collected some of this species, which are native to south Asia, so that she and her team could investigate their abilities. Testing them in a tank of water, with high-speed video capture, the research team soon found out that they use a unique combination of evolutionary adaptations to stop themselves from falling into the water.
Their findings - which were published in the scientific journal Current Biology (where you can also see a video) - found that, as with insects, surface tension was essential to geckos, which the team found out when they added soap to the tank. This addition breaks the surface tension, and made it significantly harder for them to move across the water.
Additionally, they used a similar 'leg-slapping' technique seen in basilisk lizards, which creates air pockets to help them stay above the water. This is further helped by their water-repellent skin, and quick strokes of their tails - which pushes them along as they travel.
“Geckos have this amazing superhydrophobic skin that repels water and enhances their ability to stay above the surface,” Dr Nirody said. “So in addition to surface tension and slapping, they have their own special trick.”
“They can run at a metre per second over water. Nothing else can do that; geckos are superheroes,” said Professor Robert Full, a University of California scientist as well as senior author of the paper.
It's believed that as moving through air is easier than moving through water, these water surface sprints are an especially effective strategy to escape predators - even if they swim. And, according to the team, the findings of this study could have applications in our own technology, with robotic developments that could mimic the geckos' abilities.
