The guys behind the YouTube channel, NewZulu, have managed to film the impressive power that a kangaroo can muster from its short little arms.
The team connected a camera to a drone and flew it around the Hunter Valley in New South Wales, Australia, only to stumble across a small herd of eastern grey kangaroos (Macropus giganteus) - a common species with a population of several million spread across the country. While most of the herd display little response to their new noisy visitor, what looks like a juvenile and its mother circle nervously around it, until the adult gives it a mean left hook, which knocks it right out of the sky.
According to the drone pilot, the camera was destroyed in the process, but the footage was still intact.
Eastern grey kangaroos aren't known for being aggressive - they reportedly only put about five people into hospital every year, compared to the thousands of injuries caused by family pets, and it'd be rare for one to attack without being provoked in some way. When this occurs, they will attack a human as if they were another kangaroo, grappling with them using their forearms, or sitting back on their huge hind legs and inflicting a powerful kick. You especially don't want to be on the receiving end of that second option. Here's what it looks like.
Research has shown that kangaroo forearms aren't just for batting something threatening away, they also play a very important role in courtship behaviours. Working with western grey kangaroos (Macropus fuliginosus) in Perth and Dunsborough in Western Australia last year, Natalie Warburton from Murdoch University's School of Veterinary and Life Sciences found that the males with the biggest forearms were more likely to win over and hold onto mates.
In fact, the males weren't satisfied until their arm muscles were positively bulging, Warbuton telling Garrett Mundy at ABC News, "Forelimb measurements showed that whereas female musculature growth was proportional to body size, male musculature was overwhelmingly exaggerated."
"You'll usually have a couple of really large individuals and they'll be very bulked up," Warburton's colleague Trish Fleming adds. "If you look at them from front-on, they look like they're body builders and they'll spend quite a bit of time posturing and displaying to females, but also to other males. Obviously, that's part of their competitive success."
According to their research, those males that manage to cultivate the bulkiest forearms end up paying the price - they appear to have shorter lifespans, perhaps because they have so much extra body mass to maintain. As soon as a drought sweeps the land, the lack of food will impact them far more significantly than the leaner females.