Giraffes don’t fight much, says Jessica Granweiler, a master’s student at the University of Manchester in England who studies nature’s tallest mammals. When they do, look out.
“Fighting is extremely rare because it’s extremely violent,” Ms. Granweiler said.
When older adult males joust for territory or mating rights, their hornlike pairs of ossicones thrust with the force of their long necks and can cut into their opponents’ flesh, wounding and sometimes even killing a combatant.
But some forms of giraffe dueling serve other purposes. In a study published last month in the journal Ethology, Ms. Granweiler and her colleagues reported some discoveries about sparring behavior that help giraffes establish social hierarchies. They showed that the animals didn’t take advantage of smaller members of their herds, but rather practiced their head butts with males of similar stature in ways that to a human might even appear fair or honorable.
Such findings could aid in the conservation of the dwindling populations of the animals.
Ms. Granweiler and her colleagues observed social behavior in giraffes at the small Mogalakwena River Reserve in South Africa from November 2016 to May 2017. They began to record the details of these fights — basically a who-fought-who, and how in the giraffe world.
They were surprised to find that giraffes, like humans, can be righties or southpaws when it comes to sparring. Even the youngest animals showed a clear preference, although unlike humans it seemed they were evenly split between lefties and righties.
The researchers also noticed that the younger males sparred more with each other, and nearly always chose opponents similar in size to themselves — there wasn’t a lot of bullying going on. A bar brawl effect went on as well, where one sparring match seemed to infect the crowd and prompt more fights around them.
The youngest males sparred a little differently as well. Ms. Granweiler, an undergraduate student at the time of the work, said they were likely practicing technique. They might have been gauging their strength against their peers as they swung their heads against each other’s chests and butts.
Mature adults also sparred, but they spent more time pressing their necks together in wrestling matches. Ms. Granweiler speculated that those interactions were assessments of each other’s strength without resorting to full-blown battles.
She also found that the males nearly always respected an opponent’s preference for which side to fight from. If two southpaws faced up, for example, they would match up head to tail. If one opponent was a righty and the other a lefty, they would line up head-to-head.
“I don’t know if it’s a mutual agreement — respect my side and I’ll respect yours,” Ms. Granweiler said. “Never did I see a male try and cheat.”
While the fights might be fair, they still sometimes had a referee. Ms. Granweiler said that older, mature males occasionally broke up the sparring matches between younger males. These males might be policing their peers, or they might have been trying to stop young firebrands from getting a little too confident.
“This is a clever way to sow confusion among the lower ranking males to maintain dominance and monopolize the females,” said Monica Bond, who studies giraffe social dynamics at the University of Zurich in Switzerland, but was not involved in this study. “As with most mammals, it’s a tough world out there for the guys.”
Ms. Granweiler added that “it’s also probably his way of saying ‘Don’t forget — I’m also the strongest here.’”
Dr. Bond called the paper “well done,” although she noted that it studied a population that was relatively small with some degree of possible relatedness among the individuals. While she said its inferences were valid, it was unclear whether more free-ranging males from a more genetically diverse population might behave differently.
Ms. Granweiler said that the more that we understand about giraffe behavior, the better we could manage the animals. How and when males might fight, for example, could be important information for zoo keepers or other small wildlife reserves.
Dr. Bond added that these types of social interactions can also teach us why populations might be larger or smaller in given areas — important knowledge as giraffe populations are shrinking in many parts of Africa.
“If the dominant male monopolizes the matings, then the effective population size is much smaller than it would be if all sexually mature males were able to mate,” she said. “These behaviors determine how much genetic diversity from the males gets passed on to the next generation.”