In the Presence of Older Bulls, Male Elephants Are Less Aggressive

African bull elephant.

Source: Esin Üstün, via Flickr. Distributed under a CC BY 2.0 license.

Decades of research have emphasized the importance of matriarchs in leading elephant herds. A herd, made up of related female elephants and their offspring, depends on the matriarch for guidance and leadership as they travel to find food and water, avoid danger, and bring up babies.

But much less research has investigated the relationships and connections that occur between unrelated male elephants in so-called “bull areas.”

According to a new study, the presence of older male elephants within a bull area decreases the likelihood of aggression by other males. The finding could have implications for elephant conservation efforts and human-elephant conflicts.

Male Bonding

Male African elephants leave the herd they were born into sometime in their teens and spend most of their lives apart from females. Much of their time is spent in association with other males in bull areas.

With no females around, and thus, no mating opportunities over which to fight, relationships between males in bull areas are generally positive, says the study’s first author, Connie Allen, a Ph.D. student at the University of Exeter.

She says that by associating with other males, young elephants can develop their competitive skills and assess their relative dominance to one another; learn from one another about ecological resources and social information; and improve their safety against risks from humans and predators.

Allen was inspired to take a closer look at bull society in part by reports of “delinquent” young male elephants in Pilanesberg National Park, South Africa. Young male elephants were translocated to the park as part of a reintroduction effort. But without any mature bulls in the environment, these young males prematurely entered musth — a sexually active state in male elephants characterized by high rates of aggression.

Source: Lawrence OP, via Flickr. Distributed under a CC BY-NC-ND 2.0 license.

“These hyper-aggressive males were killing rhinos and toppling vehicles and were a real danger in the park,” says Allen. “However, when older males were later reintroduced to the park, the younger males dropped out of musth and their disruptive behaviors stopped.”

For the new study, Allen conducted focal sampling of male elephants in a bull area along the Boteti River in Makgadikgadi Pans National Park, Botswana. At this site, there were no female elephants present, so bulls in musth were not an issue.

“We wanted to see if even the short-term absence of older males in a male elephant’s immediate environment affected his expression of aggressive or fearful behaviors, and to whom such aggressive behaviors are directed — other male elephants, or non-elephant targets such as other animals or vehicles,” says Allen.

The Value of Older Bulls

First, Allen and her colleagues found that adolescent elephants (aged 10-20 years) were more aggressive and fearful to non-elephant targets when they were alone compared with when they were with other males. However, rates of these behaviors in males older than 21 did not differ depending on whether they were alone or in the company of other males.

To Allen, these results suggest that adolescent elephants may feel less anxious and perceive lower levels of risk when grouped with other males. She says that buffering of predator risks may be a key benefit afforded to younger males in hanging out in groups. Adult male elephants, meanwhile, have little to fear from predators, and appear equally relaxed when alone and when with other males.

Allen and her colleagues also found that with fewer older bull elephants around (those aged 26+ years), male elephants were more likely to be aggressive towards non-elephant targets such as vehicles, livestock, and other wildlife.

Source: U.S. Fish and Wildlife Service, via Flickr. Public domain.

According to the researchers, there may be a couple explanations.

“It appears the presence of more knowledgeable, older elephants in groups may play a key role in keeping the younger, less experienced males calm and lowering their perception of their current threat level, which means there is less risk of aggression towards humans and other species,” says Allen.

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“Alternatively, older bulls may police other males’ aggression directed toward non-elephant targets.”

Living With Elephants

The findings indicate that socially isolated adolescents, and male elephants of all ages that are unable to associate with older males, may pose an increased threat to people.

“We show that the short-term absence of older males, and the lack of older males in another male’s immediate environment, are enough to influence behaviors that are potentially highly damaging to people,” says Allen.

The researchers say that wildlife managers should consider the benefits of ensuring mature bulls are present in elephant populations.

Source: Ray in Manila, via Flickr. Distributed under a CC BY 2.0 license.

In addition, these findings add to increasing concerns about the social disruptions that may occur if trophy hunting of older male elephants continues to be permitted.

“Our research suggests that the removal of older male elephants from populations through trophy hunting and poaching may lead to increases in aggression that could impact humans or their property, further driving conflict between wildlife and humans,” says Allen.

A better understanding of the complexities of elephant social relationships — among males as well as females — will be necessary for a future in which people and elephants live side by side.