Intrinsic and environmental drivers of pairwise cohesion in wild Canis social groups

Animals within social groups respond to costs and benefits of sociality by adjusting the proportion of time they spend in close proximity to other individuals in the group (cohesion). Variation in cohesion between individuals, in turn, shapes important group-level processes such as subgroup formation and fission-fusion dynamics. Although critical to animal sociality, a comprehensive understanding of the factors influencing cohesion remains a gap in our knowledge of cooperative behavior in animals. We tracked 574 individuals from six species within the genus Canis in 15 countries on four continents with GPS telemetry to estimate the time that pairs of individuals within social groups spent in close proximity and test hypotheses regarding drivers of cohesion. Pairs of social canids (Canis spp.) varied widely in the proportion of time they spent together (5%-100%) during seasonal monitoring periods relative to both intrinsic characteristics and environmental conditions. The majority of our data came from three species of wolves (gray wolves, eastern wolves, and red wolves) and coyotes. For these species, cohesion within social groups was greatest between breeding pairs and varied seasonally as the nature of cooperative activities changed relative to annual life history patterns. Across species, wolves were more cohesive than coyotes. For wolves, pairs were less cohesive in larger groups, and when suitable, small prey was present reflecting the constraints of food resources and intragroup competition on social associations. Pair cohesion in wolves declined with increased anthropogenic modification of the landscape and greater climatic variability, underscoring challenges for conserving social top predators in a changing world. We show that pairwise cohesion in social groups varies strongly both within and across Canis species, as individuals respond to changing ecological context defined by resources, competition, and anthropogenic disturbance. Our work highlights that cohesion is a highly plastic component of animal sociality that holds significant promise for elucidating ecological and evolutionary mechanisms underlying cooperative behavior.

This research was funded/supported by the School of Natural Resources at the University of Nebraska-Lincoln (John F. Benson); NSF grant DEB-1652420 (Laura R. Prugh); NSF grant DEB-1748625 (Joseph K. Bump); Pittman-Robertson Federal Aid in Wildlife Restoration Program, Safari Club International Foundation, Safari Club International Michigan Involvement Committee (Jerrold L. Belant); US DOE Office of Environmental Management under Award Number DE-EM0005228 to the University of Georgia Research Foundation, The National Geographic Society (James C. Beasley); United States Geological Survey (USGS; Shannon M. Barber-Meyer); Wildlife Conservation Society, Abruzzo Lazio and Molise National Park Authority (Paolo Ciucci), Empreendimentos Eólicos do Vale do Minho S.A. and Associação para a Conservação do Habitat do Lobo Ibérico (Francisco Álvares), Ministry of Forests, Lands, Natural Resource Operations, and Rural Development, Habitat Conservation Trust Fund, Forest Enhancement Society of British Columbia, John Prince Research Forest (Morgan L. Anderson); Government of Nunavut, Utah State University, British Broadcasting Corporation, Gulo Film Productions Ltd., John Downer Productions Ltd., Plimsoll Productions Ltd., Silverback Films Ltd., Iviq Hunters and Trappers Association, National Geographic Society, Polar Continental Shelf Program (Morgan L. Anderson and Daniel R. MacNulty), Pittman-Robertson Federal Aid in Wildlife Restoration Program (W-147-R) and the Michigan Department of Natural Resources (Dean E. Beyer); Denali National Park and Preserve, Central Alaska Inventory and Monitoring Program (Bridget L. Borg); California Department of Transportation-District 8, USGS (Erin E. Boydston and Robert N. Fisher); Parks Canada Agency (Seth G. Cherry); Ministry of Education, Science and Technological Development of Republic Serbia, Contract 451-03-68/2022-14/200178 (Duško Ćirović), Yukon-Charley Rivers National Preserve, Central Alaska Inventory and Monitoring Program (H. Dean Cluff); Rolling Plains Quail Research Ranch (Susan M. Cooper); Natural Sciences and Engineering Research Council of Canada, Ministère des Forêts, de la Faune et des Parcs du Québec (Daniel Fortin); Minnesota Environment and Natural Resources Trust Fund (Thomas D. Gable); Nature and Parks Authority of Israel (Emilio García); Max McGraw Wildlife Foundation, Cook County Animal Rabies Control (Stanley D. Gehrt); USFWS Red Wolf Recovery Program, GA Department of Natural Resources, AL Department of Conservation and Natural Resources, SC Department of Natural Resources (Joseph W. Hinton); Nevada Department of Wildlife $3 Predator Fee Program, USFWS PR Grant (Pat J. Jackson); Alberta Environment and Parks, NSERC, NSF LTREB grants #1556248 and #2038704 (Mark Hebblewhite and Evelyn H. Merrill); Natural Resources and Northern Development Manitoba, Manitoba Hydro, Manitoba Fish and Wildlife Fund, Natural Sciences and Engineering Research Council of Canada (Katrien A. Kingdon, Julie W. Turner, Eric Vander Wal, Christina M. Prokopenko, and Sana Zabihi-Seissan); Croatian Agency for Nature and Environment, Croatian Environment Fund, Bernd Thies Foundation, UK Wolf Conservation Trust, EURONATUR, Northern Velebit National Park, Velebit Nature Park, Plitvice Lakes National Park (Josip Kusak); Xunta de Galicia, Consorcio Parque Nacional Picos de Europa (Luis Llaneza); Spanish Ministry of Economy, Industry and Competitiveness (RYC-2015-18932; CGL2017-87528-R AEI/FEDER EU), GRUPIN research grant from the Regional Government of Asturias (IDI/2021/000075; José Vicente López-Bao); Natural Sciences and Engineering Research Council of Canada (Philip D. McLoughlin); Rhode Island Department of Environmental Management (Grant number: F17AF01143), US Fish and Wildlife Pittman Robertson Funds, Prince Charitable Trusts, Rhode Island Foundation (Mónia Nakamura); BC Ministry of Forests, Lands, Natural Resource Operations, and Rural Development, BC Oil and Gas Commission, BC Oil and Gas Research and Innovation Society (Matthew A. Mumma); Natural Sciences and Engineering Research Council of Canada (NSERC), Alberta Ecotrust, Canadian Wildlife Federation (Maureen H. Murray); Parks Canada, Natural Sciences and Engineering Research Council of Canada (NSERC), European Union—NextGenerationEU, under the National Recovery and Resilience Plan (NRRP), Project title “National Biodiversity Future Center-NBFC” (project code CN_00000033; Marco Musiani); Portuguese Foundation for Science and Technology, Fundação para a Ciência e a Tecnologia (SFRH/BD/144087/2019; Mónia Nakamura); Pittman-Robertson Federal Aid in Wildlife Restoration Program (Project 14.30), State of Alaska General Funds (Gretchen H. Roffler); Yukon-Charley Rivers National Preserve, Central Alaska Inventory and Monitoring Program (Mathew S. Sorum); funding was provided by the Peace/Williston Fish and Wildlife Compensation Program, Forest Investment Account, the BC Ministry of Environment, and the University of Northern British Columbia (Robin Steenweg); ISRO-IISc Space Technology Cell Grant (Maria Thaker); Wellcome Trust/DBT India Alliance Fellowship, Grant number: IA/CPHI/15/1/502028 (Abi T. Vanak); United States National Park Service, Voyaguers National Park (Steve K. Windels); Utah Divistion of Wildlife Resources (Julie K. Young). We also thank S. L. Desa, S. L. Gamesa, R. Hefner, and M. Ucko.

Peer reviewed