The Swedes, geniuses that they are, have long led the world in conquering the moose test. But here's one thing they don't seem prepared for: the kangaroo test.

Volvo began looking into how autonomous vehicles would react when encountering animals over a year ago, and they noticed these marsupials are a lot harder for computers to figure out than expected.

It turns out the hopping of a kangaroo throws off the car's detection system. The cameras and sensors aboard a self-driving car typically use the ground as a reference point. Volvo found that the system has a tough time predicting the random jumping movements of a kangaroo.

"We've noticed with the kangaroo being in mid-flight ... when it's in the air it actually looks like it's further away, then it lands and it looks closer," David Picket, Volvo Australia's technical manager, told the ABC. "If you look at a 'roo sitting at the side of a road, standing at the side of a road, in motion, all these shapes are actually different."