Asian elephants gang up in a bid to survive an increasingly human world

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  • Young male elephants, which are typically solitary, are now forming unusually large, and more long-term, all-male herds, according to a study published in Scientific Reports last week.
  • To elephants, human-dominated areas near forests, such as agricultural fields that often replace natural forests and connect one fragmented forest with another, are much like supermarkets: there is always abundant food to choose from.
  • But the risks an elephant has to run if it ventures into human-dominated areas are many: stress and physical injuries caused when people chase elephants away from crops, capture of “problem elephants,” as well as deaths due to retaliation, electrocution, train accidents and poaching.
  • According to the authors of the study, it’s “imperative that future attention is focused on the management and conservation of [these] young dispersing males” to mitigate the potential for increased human-elephant conflicts in agricultural landscapes.

Matriarch grandmas, aunts, uncles, nieces and nephews: elephants, much like us, have complex social lives. But Asian elephants in southern India could be changing their social lives just to adapt to human-use landscapes that are fast replacing their natural habitats.

Young male elephants, which are typically solitary, are now forming unusually large, and more long-term, all-male herds, according to a study published in Scientific Reports last week. This adaptation could be an effort to learn the ropes from older, more knowledgeable males on how to avoid getting killed in these areas that pose unnaturally high risks to elephants.

To elephants, human-dominated areas near forests, such as agricultural fields that often replace natural forests and connect one fragmented forest with another, are much like supermarkets: there is always abundant food to choose from. And if you’re a hungry, fast-growing, young male elephant, there’s nothing like feasting on cultivated crops (cereals like paddy and millets are far higher in nutrients such as protein, calcium and sodium than forest fare such as wild grasses) to boost growth and health, both of which are important requisites to attain mates.

Social interaction between younger and older male elephants. Image courtesy of Nishant Srinivasaiah/FEP.

Big risks, big gains

But the risks an elephant has to run if it ventures into human-dominated areas are many: stress and physical injuries caused when people chase elephants away from crops, capture of “problem elephants,” as well as deaths due to retaliation, electrocution, train accidents and poaching. But though the risks are high, so are the gains. A study in northern Karnataka state, for instance, found that crop-based diets are so rich that they even lower the stress levels of crop-foraging elephants.

Wildlife biologist Nishant Srinivasaiah would often spot such elephant herds moving across human-use areas, including farmland, near his long-term study site in Karnataka’s Bannerghatta National Park. His interest in elephant behavior even got him analyzing YouTube videos of human-elephant interactions from the region. That’s when he noticed something unusual: some of the elephant groups were comprised only or mostly of males.

“Why were male elephants moving across human-use areas?” Srinivasaiah wondered. “Where were they going? But there were other individual males who stayed largely within the forest.

“This got me interested in digging deeper into the individual idiosyncrasies and decision-making in male elephants in the landscape in general and their sociality,” he said.

To find out if environmental factors such as habitat contiguity and human presence influenced the sociality of male Asian elephants (whether an individual preferred to be alone or in a group), Srinivasaiah and his colleagues first identified an approximately 10,000-square-kilometre (3,900-square-mile) landscape that included protected areas (Bannerghatta National Park, Cauvery and Cauvery North wildlife sanctuaries), reserve forests, human settlements and agricultural land across southern Karnataka and northern Tamil Nadu.

Field surveys and information from forest guards helped the team short-list areas that both people and elephants used, to install camera traps. Of the 20,124 photographs of elephants they obtained between February 2016 and December 2017 from these camera traps, the team identified individual elephants from 1,430 photos and categorized them into three groups: mixed-sex groups (containing male and female elephants), all-male groups, and solitary males. The team then categorized each of the 248 male elephants they identified from these groups into age classes. Age correlates with sexual maturity, so the team could also classify every male as either a juvenile (less than 10 years old and sexually immature), adolescent or sexually mature but socially immature (10 to 20 years), or mature (both sexually and socially mature, more than 20 years of age).

Recent long-term associations

As expected, the photographs revealed that juvenile males were spotted mostly in mixed-sex groups; male elephants continue to stay in the herd they are born into until they hit adolescence. The results also revealed that in forest habitats, male elephants tended to become increasingly solitary with age. Male bulls were, therefore, mostly solitary. But adolescents were either solitary or in all-male groups, in equal proportions. These males were most likely to be part of all-male groups and grouped with other males in large herds of up to 12 elephants, almost exclusively in croplands also containing isolated forest patches — a sign that these recent all-male groups could be there in response to environmental factors.

These all-male groups also stuck together for an unusually long time. While it’s common for some males to team up with others for a single season or a few weeks, these new all-male groups lasted for “a few years,” according to the authors. Interestingly, studies conducted in the same region more than two decades earlier don’t mention such large and stable all-male groups at all, the authors add.

These male elephants forming long-term associations is more than just co-occurrence or grouping by chance, says Srinivasaiah. One possibility is “social buffering,” where the social support system derived from being part of a group can help “buffer” or reduce stress. While social buffering is a known phenomenon among elephants, there could be another reason these adolescent male elephants are grouping together, Srinivasaiah said.

“These elephants need to learn to utilize the novel landscape efficiently and to avoid getting killed,” he said. “Hence, associating with older, more knowledgeable and experienced males is a strategy used by some of the younger males to survive and persist in high-risk landscapes. Otherwise, they would have had to do the same through trial and error, which could be costly.”

The establishment of these all-male groups in response to anthropogenic factors, thereby modifying their own sociality, is an important finding that suggests not just how adaptable elephants are, but also how human influence is changing the natural life around us, Srinivasaiah said.

Anthropocene woes

Widespread habitat loss is one of the hallmarks of the Anthropocene, the geological age defined by pervasive human influence on the natural world. If elephant home ranges within forests continue to be taken over for non-forest activities, the animals will have to adapt to the change or perish, Srinivasaiah said.

“Elephants are survivors, hence most often they will choose alternative ways to persist; and feeding from crop fields even if it’s risky cannot be discounted,” he said.

Elephants are arguably one of the most adaptive of mammalian species, and their social behavior may vary depending on environmental conditions, says Prithiviraj Fernando, trustee of the Centre for Conservation and Research in Sri Lanka, who studies Asian elephants in the island nation and was not involved in the recent study in India.

“For example in Sri Lanka, large all-male groups are observed primarily in areas with high resource availability,” he said.

This study is one of the first to focus on male Asian elephant sociality and how it varies in relation to habitat conditions, he wrote in an email to Mongabay. “Conducting studies similar in other parts of the range would help determine whether the patterns observed by Srinivasaiah and his colleagues are unique to their study area or characteristic of Asian elephants everywhere,” Fernando said.

A solitary adolescent male elephant caught on camera trap at night within forested habitat. Image courtesy of Nishant Srinivasaiah/FEP.

Mitigating conflict

According to the authors of the study, it’s “imperative that future attention is focused on the management and conservation of [these] young dispersing males” to mitigate the potential for increased human-elephant conflicts in agricultural landscapes.

“Young dispersing males are very impressionable and if associated with non-crop foraging older bulls, will not learn crop-foraging behavior or can even unlearn it,” Srinivasaiah said. Mitigation measures such as capturing key individuals within a bull group may therefore backfire, he said, as these older and experienced bulls are essential in a male elephant society to help guide the younger bulls and also discipline them when moving across villages, thus keeping conflict to a minimum.

“The key to living with elephants may lie in understanding their social complexity and harnessing this new found knowledge to learn how to modify our own lifestyle practices to make them more compatible with the elephants’ use of an area, and be more flexible in our own approaches and behavior towards elephants,” Srinivasaiah said.

 

Citations:

Srinivasaiah, N., Kumar, V., Vaidyanathan, S., Sukumar, R., & Sinha, A. (2019). All-male groups in Asian elephants: A novel, adaptive social strategy in increasingly anthropogenic landscapes of southern India. Scientific Reports9(1). doi:10.1038/s41598-019-45130-1

Sukumar, R. (1990). Ecology of the Asian elephant in southern India. II. Feeding habits and crop raiding patterns. Journal of Tropical Ecology6(1), 33-53. doi:10.1017/s0266467400004004

Pokharel, S. S., Singh, B., Seshagiri, P. B., & Sukumar, R. (2018). Lower levels of glucocorticoids in crop‐raiders: Diet quality as a potential ‘pacifier’ against stress in free‐ranging Asian elephants in a human‐production habitat. Animal Conservation22(2), 177-188. doi:10.1111/acv.12450

 

Banner image of an all-male elephant group moving toward a banana plantation on the outskirts of Bengaluru, India, courtesy of Nishant Srinivasaiah/FEP.

This story first appeared on Mongabay

South Africa Today – Environment



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