Social Structure in South Indian Elephants

Guest post by Nandini Shetty

A group of elephants visit the grasslands surrounding the Kabini Reservoir in Southern India. Photo: Kabini Elephant Project

India includes some of the largest populations of Asian elephants in the world: an estimated ~26 000 to 28 000 elephants distributed across four regions. Of the four regions, southern India includes the single largest population of Asian elephants in the world (~14 000) and elephants are distributed across the Western and Eastern Ghats.

I studied the ecology and behaviour of Asian elephants as part of an ongoing long-term project on elephants, the Kabini Elephant Project, which was started in March 2009 to study the social life of elephants. I worked in Nagarahole and Bandipur National Parks in Karnataka, southern India. Both National Parks are separated by the River Kabini and a dam was constructed across the river in the 1970s. When the dam is opened, receding waters expose the wet ground which supports the growth of fresh grass. As ponds dry up inside the forests in summer, many herds of elephants visit and aggregate along the backwaters area.

Male elephants disperse away from their natal groups when they reach adolescence, sometimes forming temporary associations with other males. Female elephant groups are dynamic, most likely including maternal relatives: mothers, daughters, aunts, cousins, nieces and so on. The group composition and size keeps changing with time. On some occasions, large groups undergo fission and form small groups, while on other occasions, small groups join other groups and form large groups. These “fission – fusion” events are thought to be in response to competition for food. It was found in other species that when food resources are limited or scarce, groups undergo fission and when food resources are plentiful, groups fuse. African savannah elephants show a hierarchical, “multi-tiered” fission – fusion society, where the largest grouping is called a clan. A clan contains family groups and bond groups and is a community that is defined on the basis that females associate more with others within their own community than those outside it. Earlier studies on Asian elephants of Uda Walawe, Sri Lanka by UWERP show a multi-level society, but not exactly equivalent to family groups or bond groups of African savannah elephants (Moss and Poole 1983, Wittemeyer et al. 2005, de Silva et al. 2011, de Silva and Wittemyer 2012).

Asian elephants in Southern India also exhibit fission-fusion social dynamics. Photos: Kabini Elephant Project

At the level of different clans, there was no consistent effect of season on group size or associations. A reason could be that there is a constraint on group size in this population (which is why larger and smaller clans have similar average group sizes). How food resources are spaced in the forest may not be very different across seasons (but this is something that remains to be studied). We found that females maintained their associates across seasons and also associated with them to roughly the same extent across years (Nandini et al. 2017).

We also compared the Kabini population (using similar data collection methods) with the Samburu African savannah elephant population and the Uda Walawe Asian elephant population with data kindly provided by the authors of those studies. Of the three populations, the African savannah elephant was the most cohesive, with strong associations between females, followed by the Kabini, and then the Uda Walawe populations. However, the group sizes in the three populations were also different: ~5 females in Samburu per group on average, compared to ~3 in Kabini and Uda Walawe. We were able to show that there are basic underlying similarities amongst the three populations in female social structure, but the differences in group sizes prevent these similarities from being easily seen. Larger groups formed by the African elephants allow females to associate with many females, thus making them more cohesive, compared to the Kabini elephants (Nandini et al. 2018).

We think that differences in group sizes across species may result from differences in their ecology. Savannah ecosystems offer large amounts of grass biomass, supporting large groups, as opposed to the tropical forests that Asian elephants inhabit, in which food resources are patchy and limited. African elephants also face predation risk from lions and poaching pressure from humans, which may have made them more gregarious and cohesive. Among Asian elephant populations, Kabini was more cohesive than Uda Walawe. This possibly stemmed from the large scale historic disturbance that Sri Lanka went through, which resulted in killing of thousands of elephants in the 19th century. Such disturbance is likely to have affected the associations among female elephants in Sri Lanka. But more studies on other populations are required to test this idea.

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References:

  • Moss CJ, Poole JH. 1983. Relationships and social structure in African elephants. In: Hinde RA, editor. Primate social relationships: an integrated approach. Oxford: Blackwell. p. 315–325.
  • Wittemyer G, Douglas-Hamilton I, Getz WM. 2005. The socioecology of elephants: analysis of the processes creating multitiered social structures. Animal Behaviour 69: 1357–1371.
  • de Silva S, Ranjeewa AD, Kryazhimskiy S. 2011. The dynamics of social networks among female Asian elephants. BMC Ecology 11:17.
  • de Silva S, Wittemyer G. 2012. A comparison of social organization in Asian elephants and African savannah elephants. International Journal of Primatology 33:1125–1141.
  • Nandini S, Keerthipriya P, Vidya TNC. 2017. Seasonal variation in female Asian elephant social structure in Nagarahole-Bandipur, southern India. Animal Behaviour 134: 135-145.
  • Nandini S, Keerthipriya P, Vidya TNC. 2018. Group size differences may mask underlying similarities in social structure: a comparison of female elephant societies. Behavioural Ecology 29: 145-159.
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News that caught our attention

Before we start, a disclaimer: there’s a lot of bad news out there. We’re not going to amplify it by reposting here. But we thought it would be nice to highlight interesting news every now and then. Things that give us hope (#ElephantOptimism) and/or make us think.

Here are a couple.

  1.  To bee (hive-fence) or not to bee (hive-fence)

Image: Bangkok Post

We recently published the results of a study done back in 2014 with Dr. Lucy King of the Elephants and Bees Project showing that Asian elephants are not very keen on bees (read the blog post here).  But of course, plenty of people had heard about the earlier studies with African elephants and had already jumped to the final step – beehive fences as a means of deterring crop raiding. Continue reading

The Secret Life of Elephants

We have the pleasure of watching elephants in broad daylight in precious few places like Udawalawe, where they are habituated enough to be placid and tolerant of onlookers. Indeed, one can get rather spoiled in this particular Park, because even the birds are unafraid and will happily sit and pose for your clumsy photograph from inches away. At times, certain exhibitionist pachyderms even appear to put on a show for the gawking crowds:

But all is not paradise. Continue reading

The Buzz about Elephants and Bees

An elephant family rests under a tree in the hot midday heat. Situations like this were perfect for the playback experiments.

by SdS

In October 2007 Lucy King and colleagues first made a splash by reporting that African elephants seemed to be rather put off by bees.  I was still in Sri Lanka during my big “data collection year” as a graduate student, trying to figure out the social relationships among Asian elephants and recording vocalizations whenever I got a chance. Lucy’s first paper was a curiosity, but then three years later she followed it up with the even more intriguing finding that African elephants even produce alarm calls specific to bees. This got the attention of my advisor at Penn, Dorothy Cheney, who having expended considerable time thinking about such things as monkey alarm calls, dropped me a one-liner: “Have you seen this?” Continue reading

Sumedha’s Epic Musth

Sumedha shows all signs of musth as he consorts with Indika (Sandamali) in 2011, which include secretions from the temporal glands on the sides of his head and urine dribbling.

Of all the iconic tuskers that have passed through Udawalawe over the years, Sumedha is the one I’ve known longest. All tuskers are distinctive, because they’re so rare in Udawalawe, but Sumedha additionally had a nice big hole in his left ear and an awkward  tail with no hair. He wasn’t as regal as my beloved Raja, nor as old and wise as the Kalthota tusker, both of whom would have been easily dominant over him in the early years. But he was younger than either of them, and built like a tank. So if he survived, eventually his time would come. Continue reading

Evolving A More Egalitarian Elephant

coverphoto

A young female named Right Hole puts her trunk over the head and back of another female of similar age with the ID [458]. The two are from different social groups, though they know each other.

Elephants are commonly thought to live in matriarchal societies which rely on the strong leadership and wisdom of elders, with strong age-based dominance hierarchies. Our new study in the journal Behavioral Ecology overturns this view, finding that in fact Asian elephants, unlike African savannah elephants (Loxodonta africana), do not exhibit clear dominance hierarchies or matriarchal “leadership” [1]. Continue reading

Ethimali Finds Her “Forever Home” In The Wild

by DJ, USW, and SdS (Photos by DJ &UWERP)

The female orphaned elephant calf found in Ethimale, Southern Sri Lanka rescued and brought to Elephant Transit Home (ETH), Udawalawa was later named Ethimali. After several years of rehabilitation, she was released to Uda Walawe National Park in March 2004, when she was about 4 years old, with another 10 rehabilitated juveniles.

Some young females at the ETH show an array of maternal or allomothering characters from an early age, despite being orphans themselves. They seem to select calves out of new arrivals and try to be as attentive to them as possible. She frequently checks whether her orphan is alright and will be the first to respond if the orphan screams or is attacked by another calf. She keeps continuous company for the orphan and with time, it starts to follow her most of the day. When the orphan seeks comfort she allows it to suck on her – in the absence of real milk, even the tip of an ear will do!

Ethimali (wearing a belt around the neck) with Mahee, a wild adult female and her calf.

Ethimali (wearing a belt around the neck) with Mahee, a wild adult female and her calf in 2004.

Continue reading