But tiny new robots being developed at Stanford University are giving them a run for their money with the ability to pull up to 1,800 times their own weight.

When it comes to finding new ways of getting around, robotics experts turn to nature for inspiration time and time again. Many robots walk like insects, some slither like snakes, others swim like jellyfish, and quite a few can fly like birds.

By making use of what's known as the van der Waals force, the same force used by ants to pull heavy loads and by geckos to climb on vertical glass walls, Stanford researchers have developed "MicroTugs" – tiny robots that, through use of a special directional adhesive, can pull nearly 2,000 times their own weight.

The robot's design incorporates a strong adhesive deposited onto a series of 100-micrometer flexible wedges made of silicone rubber. Under normal conditions, only the very tips of the wedges make contact with the surface underneath, meaning that the robot is essentially free to move without resistance. But the microrobots are also able to push the wedges down, which makes them stick firmly to the ground when needed.