If four legs are good and two are bad, are six even better? That’s the question roboticists have been trying to answer for a decade, ever since boffins at the University of Pennsylvania, as part of a large DARPA-funded consortium, invented the RHex Hexapedal Robot platform.

While the RHex is traditionally used for experiments on land, Researchers at McGill University, in partnership with Dalhousie University and York University, have also succeeded in buidling AQUA, which can swim underwater - even in the open ocean.

Which is how this happened. What you’re seeing is a robot’s-eye view:

Robot 1, mother nature 0.

It’s all part of a larger effort to use a standard robotic platform to experiment with strategies for sensing the environment and adjusting the robot’s locomotion to navigate appropriately. Robotics, like computing, is becoming standardized: platforms like RHex allow students and researchers to build on a known system rather than having to re-invent the wheel each time. It’s code re-use, but for robots.

This facilitates stepwise innovations. Here’s the AQUA switching gaits as it goes from land to sea:

Diving:

Climbing a hill:

Following a diver, reading gestures, clambering onto land like a primordial lungfish, etc.:

Hexapodal robots are simple and robust enough that Boston Dynamics, makers of the BigDog pack robot, built a version for the Army. You can tell it’s militarized because in every publicity shot, it’s covered with a Rambo-esque quantity of camouflaging muck.

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