During mating season, koala males become vocal and aggressive to attract females. Unlike the rest of the year when they spend most of their time in the trees, koalas spend more time on the ground moving from tree to tree to find a mate. Males use scent to let the females know that they are in the area. Females often resist mating attempts, submitting to familiar or more dominant males.
As the outdoor temperatures start to increase, males begin their mating ritual. Their grunts and calls are loud enough to hear over a mile away. According to LiveScience, this call is to advertise the size of the koala, with larger males being preferred by females due to the greater chance of survival for their offspring.
The distinctive scent of the male comes from urine and a scent gland on its chest. The male rubs this gland on limbs as he climbs. According to ABC Science, this heady aroma, with undertones of eucalyptus, is one that is not easily forgettable.
As the male attempts to mate with the female, her resistance and screams often attract other males. Her suitor must then fight off the other male koalas, giving the female a chance to determine the dominant male.