while vertical transmission (parent-offspring) is a common element of song learning, horizontal transmission among animals of the same generation can also occur. male humpback whales produce various songs over their lifetime, which are learned from other males in the population. males in a population conform to produce the same mating song, consisting of a highly stereotyped vocal display involved in mate attraction. the cultural transmission of these songs has been found to occur across great geographic distances over years, with one study noting song transmission across the western and central south pacific ocean populations over an 11-year period.