Starting Points
Female fertility and infant survivorship increase following lethal intergroup aggression and territorial expansion in wild chimpanzees
Brian Wood et al.
Proceedings of the National Academy of Sciences, 25 November 2025
Abstract:
Lethal coalitionary intergroup aggression is a conspicuous aspect of wild chimpanzee behavior. Evidence indicates that such violence can lead to territorial expansion, but whether this results in fitness benefits is unknown. Here, we show that female fertility and infant survivorship increased after males in the Ngogo chimpanzee community killed members of neighboring groups and expanded their territory. These findings demonstrate the fitness benefits of intergroup killing in one of our two closest living relatives and contribute to the debate regarding its adaptive significance.
Hormonal Mechanisms of Grandmothering: The Coevolution of Physiology, Life History and Behavior
Natalie Dinsdale, Aiden Bushell & Bernard Crespi
Human Nature, September 2025, Pages 360-381
Abstract:
The evolution of menopause, grandmothering and long lifespan represent key events in the evolution of human life history. Demographic studies have amply demonstrated inclusive fitness benefits from grandmaternal care, but the hormonal bases of such care, and how it evolved in relation to other reproductive and demographic traits, have yet to be addressed in detail. We propose and evaluate a novel hypothesis for the coevolution and adaptive covariation of life history, physiology, and behavior among women in this context. The hypothesis centers on relatively low testosterone, which promotes: (1) earlier, higher fertility and fecundity, (2) earlier cessation of ovarian activity (leading to earlier grandmothering), and (3) enhanced alloparental care. The hypothesis can help to explain among-female variation in grandmaternal care, and potential trajectories for the concerted evolution of grandmothering, prolonged human lifespan, and associated life history traits. A suite of convergent evidence supports the hypothesis, and it makes new predictions that are straightforward to test.
The dispersal of domestic cats from North Africa to Europe around 2000 years ago
Marco De Martino et al.
Science, 27 November 2025
Abstract:
The domestic cat (Felis catus) descends from the African wildcat Felis lybica lybica. Its global distribution alongside humans testifies to its successful adaptation to anthropogenic environments. Uncertainty remains regarding whether domestic cats originated in the Levant, Egypt, or elsewhere in the natural range of African wildcats. The timing and circumstances of their dispersal into Europe are also unknown. In this study, the analysis of 87 ancient and modern cat genomes suggests that domestic cats did not spread to Europe with Neolithic farmers. Conversely, they were introduced to Europe around 2000 years ago, probably from North Africa. In addition, a separate earlier introduction (first millennium before the common era) of wildcats from Northwest Africa may have been responsible for the present-day wild population in Sardinia.
Megalithic statue (moai) production on Rapa Nui (Easter Island, Chile)
Carl Philipp Lipo et al.
PLoS ONE, November 2025
Abstract:
Ethnohistoric and recent archaeological evidence suggest that Rapa Nui (Easter Island, Chile) was a politically decentralized society organized into small, relatively autonomous kin-based communities across the island. The more than 1,000 monumental statues (moai) of Rapa Nui thus raise a critical question: was production at Rano Raraku — the primary moai quarry — centrally controlled or did it mirror the decentralized pattern found elsewhere on the island? Using Structure-from-Motion (SfM) photogrammetry with over 11,000 UAV images, we created the first comprehensive three-dimensional model of the quarry to test these competing hypotheses. Our analysis reveals 30 distinct quarrying foci distributed across the crater, each containing redundant production features and employing varied carving techniques. This spatial organization, combined with evidence for multiple simultaneous workshops constrained by natural boundaries, indicates that moai production followed the same decentralized, clan-based pattern documented for other aspects of Rapa Nui society. These findings challenge assumptions that monumentality requires hierarchical control, instead supporting emerging frameworks that recognize how complex cooperative behaviors can emerge through horizontal social networks. The high-resolution 3D model also establishes a crucial baseline for the cultural heritage management of this UNESCO World Heritage site, while advancing methodological approaches for testing sociopolitical hypotheses through the spatial analysis of archaeological landscapes.
A 12,000-year-old clay figurine of a woman and a goose marks symbolic innovations in Southwest Asia
Laurent Davin, Natalie Munro & Leore Grosman
Proceedings of the National Academy of Sciences, 25 November 2025
Abstract:
Paleolithic representations of human-animal interaction are rare, with only a few painted or engraved examples recorded in Upper Paleolithic contexts, mostly from Europe. Such scenes, depicting real or imagined interactions, are of major importance for understanding a wide range of past human perspectives, starting with how people conceived of their ontological relationship with the environment and nonhuman beings. In the Early Neolithic in Southwest Asia, shifts in perspective led human communities to manipulate and transform their environment while simultaneously depicting new forms of art featuring human-animal interactions. Here, we describe the recent discovery of the earliest figurine depicting a human-animal interaction — a woman and a goose — from the Late Epipaleolithic (c. 12,000 years cal. BP) village of Nahal Ein Gev II in northern Israel. The artistic techniques and raw materials that were used and the mythological scene that was depicted appear earlier than previous examples, foreshadowing the more monumental changes in symbolic expression that occur in the following Neolithic periods. Through technological, archaeometric, and dermatoglyphic analyses, we demonstrate that this unique figurine was meticulously modeled from clay using innovative techniques that created perspective using form and light. Importantly, the figurine captures a mythological scene between the woman and the goose that is consistent with an animistic belief system. Through our combined multidisciplinary approach, this study provides important original data regarding the antiquity and development of symbolic expression using clay at the end of the Epipaleolithic at a crossroads between early sedentary and fully Neolithic societies in Southwest Asia.
New finds shed light on diet and locomotion in Australopithecus deyiremeda
Yohannes Haile-Selassie et al.
Nature, forthcoming
Abstract:
The naming of Australopithecus deyiremeda from Woranso-Mille (less than 3.59 to more than 3.33 million years) indicated the presence of a species contemporaneous with Australopithecus afarensis in the Ethiopian Afar Rift. A partial foot (BRT-VP-2/73) and several isolated teeth from two Burtele (BRT) localities, however, were not identified to the species level. Recently recovered dentognathic specimens clarify not only the taxonomic affinity of the BRT hominin specimens but also shed light on the diet and locomotion of A. deyiremeda. Here we present a comparative description of these specimens and show that they are attributable to A. deyiremeda. We also find it parsimonious to attribute the BRT foot to this species based on the absence of other hominin species at BRT. The new material demonstrates that overall, A. deyiremeda was dentally and postcranially more primitive than A. afarensis, particularly in aspects of canine and premolar morphology, and in its retention of pedal grasping traits. Furthermore, the low and less variable distributions of its dental enamel δ13C values are similar to those from Ardipithecus ramidus and Australopithecus anamensis, indicating a reliance on C3 foods. This suggests that A. deyiremeda had a dietary strategy similar to the earlier A. ramidus and A. anamensis. The BRT foot and its assignment to A. deyiremeda provides conclusive evidence that arboreality was a significant component of the positional behaviour of this australopith, further corroborating that some degree of arboreality persisted among Pliocene hominins.