Fighting is dangerous – even minor fights can lead to injury, and most fights require focus, which distracts the animal from watching out for predators.
Many male animals use body language or bluff to avoid fighting. Male kangaroos use expressive gestures to show other male kangaroos how strong they are, and thus avoid fighting unnecessarily.
Kangaroo bluff display consists of these moves, usually in this order:
Exaggerated pentapedal walking
Kangaroos ‘walk’ by moving their front legs forward, then balancing on their tails for a moment to shift their back legs forward. Its called the pentapedal walk (penta = five, pedal = feet, including the tail). When displaying a male kangaroo will exaggerate this walk by pushing his shoulders and forearms forward, highlighting his muscles. He will arch his back and balance on his tail for longer than normal.
Ball handling and exaggerated grooming
Kangaroos scratch themselves a lot, just as a part of normal grooming. But a male kangaroo avoiding a fight will groom to an extreme degree – its a great way to show nonchalance, but also how pronounced and large their muscles are.
When watching others males display or fight, some male kangaroos will groom their testicles a lot by holding them in their hands and stroking them repeatedly. This doesn’t appear to be masturbation – I haven’t seen it lead to an erection.
During the pentapedal walk, male kangaroos will pause to rub their chest against the ground, by dropping one shoulder to the ground and rubbing back and forth. This spreads their scent and alerts other males to their presence.
Also during a pause in the pentapedal walk, a male kangaroo will grab a tuft of grass in his hand and pull it out and throw it away. This shows off his strength (and probably his arrogance). He will also claw at the ground and throw dust in the air.
This is the most extreme of displays and requires great strength. The kangaroo will raise his body to a normal upright position, then extend on to his tip toes. Its the same thing they do to hop, but more vertical, and held for longer. This position can give a kangaroo an extra 40cm of height.
Only very large, strong kangaroos can maintain high standing for long durations. It is the supreme demonstration of their fitness and strength. A rival male seeing this might avoid fighting if he can’t high-stand for as long.
Kangaroos in the wild are fascinating social animals. Watching male kangaroos avoid fighting is just as interesting as watching kangaroos fight.
Watch kangaroos fight and avoid fights on Echidna Walkabout’s Sunset Koalas & Kangaroos IN THE WILD tour near Melbourne.