Elephant communities fracture as losses outpace newcomers

Elephant societies in Sri Lanka

Elephants live in complex societies that hold together despite individual deaths and movements.

Study of Asian elephants

Anastasia Madsen and colleagues analyzed 12 years of observations of wild Asian elephants in Sri Lanka.

Udawalawe National Park

The park was created in the 1970s around a reservoir on one of Sri Lanka’s four major rivers.

Park transformation

The park became grassland after settlers left, attracting elephants but later facing invasive plants.

Invasive plants problem

Invasive plants like lantana create impenetrable thickets that reduce elephant forage and movement.

“In some places, they’re like an impenetrable thicket. Not even elephants really like to go there because there’s no food for them”

Elephant social structure

Females form fission-fusion societies with shifting group memberships.

Social network analysis

Researchers mapped elephant relationships to identify communities within the social network.

Early signs of fracture

Communities began to fracture as losses outpaced new members by 2012.

Population decline

By 2018, 69 percent of the original females were gone despite elephants living up to 60 years.

Fracturing process

Fracturing started with weak ties, then progressed to stronger relationships.

“The first ties to go were the weakest, the casual acquaintances”

Flickering lights

Network fluctuations before collapse could serve as early warning signs.

Current challenges

Elephant populations face human conflict and habitat loss, reducing survival rates.