Researchers have built a tank-like robot that can climb smooth walls with the ease of a gecko scurrying about in the middle of the night. In fact, the robot was inspired by a scientific explanation for what makes gecko feet so sticky.

The robot could find use in applications ranging from inspections of pipes, buildings, and nuclear power plants to search and rescue missions.

Its tank-like feet are inspired from the millions of tiny, hair-like toe pads on gecko feet that allow the lizards to scurry up trees, walls, and across ceilings without falling down. 

Previous research explained that tiny toe pads accomplish this thanks to what are known as van der Waals forces, very weak attractive forces between molecules.

The robot team, led by Jeff Krahn at Simon Fraser University in Burnaby, Canada, recreated these dry but sticky toe pads in the lab using the material polydimethysiloxane (PDMS). The end of each hair-like pad contains a mushroom cap shape that is 17 micrometers wide and 10 micrometers high.

"While van der Waals forces are considered to be relatively weak, the thin, flexible overhang provided by the mushroom cap ensures that the area of contact between the robot and the surface is maximized," Krahn explained in a news release. 

By using the gecko-like pads on the robot, the researchers are able to climb even smooth surfaces such as glass or plastic, materials that are a consistent challenge for robots that use magnets, suction cups, spines and claws to climb.

The tank-like robot weighs in at 240 grams and can transfer from a flat surface to a wall over inside and outside corners. It has a top speed of 3.4 centimeters per second.

The robot goes by the name Timeless Belt Climbing Platform (TBCP-II). It is outfitted with sensors that allow it to detect its surroundings and alter its course to navigate obstacles, though Krahn and his team are still improving the control strategy to make it fully autonomous.

To see the robot climb the wall, be sure to check out the video at the top of this post. Krahn and colleagues describe the robot today in the journal Smart Materials and Structures.

More on geckoes and robots:

• Gecko's sticky secrets inspire new bandages
• Geckos inspire new breed of glue
• How geckos land on their feet
• Look out, Spider Man! Gecko inspires new glue
• Robot base jumps from wall
• No obstacle too high for climbing snakebots

U.S. Fish and Wildlife Service

Black-billed magpies are among the few wild animals that have been shown to recognize humans.

Add the black-billed magpie to the list of birds that can recognize individual humans who pose a threat, scolding them when they approach, according to a new study.

The birds are part of the crow family, among the most intelligent animals. Previous studies have shown, for example, that crows can wield tools to find food and American crows have been shown to recognize humans who threaten their nest or captured them.

Until now, however, experimental evidence was lacking that magpies would do the same.

This changed in 2009 when Won Young Lee, a doctoral student at Seoul National University in Korea, was constantly taking eggs out of magpie nests for a long-term survey project and started to be followed and scolded by the nest owners.

He tried to fool the magpie by giving his cap to another person. "This did not work. When I moved away, the bird followed me rather than the fellow observer wearing my cap," he said in a news release. 

The researchers followed up on this finding with a controlled experiment. A pair of humans, a climber who went up to nests and a non-climber, wearing the same clothes, were presented to the magpies. All the magpies showed aggression to the climbers, but not the non-climbers.

The researchers suggest the birds learn to recognize the threatening humans by vision, learning over time to distinguish individual faces. If so, magpies would be most likely to recognize humans in urban settings, a theory the team plans to test.

The findings have been accepted for publication in the journal Animal Cognition.