@article {333531,
	title = {Lethal conflict after group fission in wild chimpanzees},
	journal = {Science},
	volume = {392},
	year = {2026},
	month = {2026/04/09},
	pages = {216-220},
	abstract = {<p>Territorial conflicts in animals can inform aspects of human warfare, but civil war, with its shifting group identities, has not been previously observed. We report a rare, permanent fission in the largest-known group of wild chimpanzees (<i>Pan troglodytes</i>). Using 30 years of behavioral observations and network analyses, we describe a transition from cohesion to polarization in 2015 and the emergence of two distinct groups by 2018. Over the next 7 years, members of one group made 24 attacks, killing at least seven mature males and 17 infants in the other group. These findings indicate that group identities can shift and escalate into lethal hostility in one of our closest living relatives in the absence of the cultural markers often thought necessary for human warfare.</p>
},
	isbn = {0036-80751095-9203},
	doi = {https://doi.org/10.1126/science.adz4944},
	url = {https://www.science.org/doi/10.1126/science.adz4944},
	author = {Sandel, Aaron A. and He, Yixuan and Ren, Junpeng and Kei, Yik Lun and Lee, Kevin C. and Clark, Isabelle R. and Reddy, Rachna B. and Negrey, Jacob D. and Birungi, Charles and Apamaku, Blessing A. and Kanweri, Diana and Kalunga, Davis and Aliganyira, Christopher and Ram{\'\i}rez-Amaya, Sebasti{\'a}n and Nakayima, Phionah and Katumba, Raymond and Kamugyisha, Brian and Acosta-Florez, Daniela and van Boekholt, Bas and Mbabazi, Godfrey and Akamumpa, Erone and Namaganda, Sharifah and Tumusiime, Alfred and Angedakin, Samuel and Reinert, Gesine and Madrid-Padilla, Oscar and Cucuringu, Mihai and Wipf, David and Langergraber, Kevin E. and Watts, David P. and Mitani, John C.}
}
