When the wild things are: Defining mammalian diel activity and plasticity
Authors: Devarajan Kadambari , Fidino Mason , Farris Zach J. , Adalsteinsson Solny A. , Andrade-Ponce Gabriel , Angstmann Julia L. , Anthonysamy Whitney , Aquino Jesica , Asefa Addisu , Avila Belen , Bailey Larissa L. , de Sousa Barbosa Lyandra Maria , de Frias Barreto Marcela , Barton Owain , Bates Chloe E. , Beltrão Mayara Guimarães , Bird Tori , Biro Elizabeth G. , Bisi Francesco , Bohórquez Daniel , Boyce Mark , Brashares Justin S. , Bullington Grace , Burns Phoebe , Burr Jessica , Butler Andrew R. , Calhoun Kendall L. , Cao Tien Trung , Casado Natalia , Cepeda-Duque Juan Camilo , Cepek Jonathon D. , Chiarello Adriano Garcia , Collins Merri , Cordeiro-Estrela Pedro , Costa Sebastian , Cremonesi Giacomo , Cristescu Bogdan , Cruz Paula , de Albuquerque Anna Carolina Figueiredo , De Angelo Carlos , de Campos Cláudia Bueno , de Sena Liana Mara Mendes , Di Bitetti Mario , de Matos Dias Douglas , Diefenbach Duane , Doherty Tim S. , dos Santos Thais P. , Duarte Gabriela Teixeira , Eppley Timothy M. , Erb John , Esteves Carolina Franco , Evans Bryn , Falcão Maria L. M. , Fernandes-Ferreira Hugo , Fieberg John R. , de Souza Filho Luiz Carlos Firmino , Fisher Jason , Fortin Marie-Josee , Gale George A. , Gallo Travis , Ganoe Laken S. , Garcia-Anleu Rony , Gaynor Kaitlyn M. , Gelmi-Candusso Tiziana A. , Gichuru Phillys N. , Gomez Quimey , Green Austin M. , Guimarães Luiza Neves , Haight Jeffrey D. , Harris Lavendar R. , Hawn Zachary D. , Heiman Jordan , Hoang Huy Quoc , Huebner Sarah , Iannarilli Fabiola , Iezzi María Eugenia , Ivan Jacob S. , Jaspers Kodi J. , Jordan Mark J. , Kamilar Jason , Kane Mamadou , Karimi Mohammad Hosein , Kelly Marcella , Kohl Michel T. , Kuvlesky William P. , Ladle Andrew , Larson Rachel N. , Le Quy Tan , Le Duy , Le Van Son , Lehrer Elizabeth W. , Lendrum Patrick E. , Lewis Jesse , Link Andrés , Lizcano Diego J. , Lombardi Jason V. , Long Robert , López-Tello Eva , Lugarini Camile , Lugo David , MacKay Paula , Madadi Maria , Magalhães Rodolfo Assis , Magle Seth B. , Maia Ludmila Hufnagel Regis Diniz , Mandujano Salvador , Marchenkova Taisiia , Marinho Paulo Henrique , Marker Laurie , Pardo Julia Martinez , Martinoli Adriano , Massara Rodrigo Lima , Masseloux Juliana , Matiukhina Dina , Mayer Amy , Mazariegos Luis , McClung Maureen R. , McInturff Alex , McPhail Darby , Mertl Amy , Middaugh Christopher R. , Miller David , Mills David , Miquelle Dale , Miritis Vivianna , Moll Remington J. , Molnár Péter , Montgomery Robert A. , Morelli Toni Lyn , Mortelliti Alessio , Mueller Rachael I. , Mukhacheva Anna S. , Mullen Kayleigh , Murphy Asia , Nepomuceno Vance , Ngoprasert Dusit , Nguyen An , Van Nguyen Thanh , Nguyen Van Thai , Quang Hoa Anh Nguyen , Nipko Rob , Nobre Ana Clarissa Costa , Northrup Joseph , Owen Megan A. , Paglia Adriano Pereira , Palmer Meredith S. , Palomo-Munoz Gabriela , Pardo Lain E. , Parks Chrystina , de Oliveira Paschoal Ana Maria , Patterson Brent , Paviolo Agustin , Pejchar Liba , Pendergast Mary E. , Perotto-Baldivieso Humberto L. , Petrov Timofei , Poisson Mairi K. P. , Polli Daiana Jeronimo , Pourmirzai Morteza , Reebin Alexander , Remine Katie R. , Rich Lindsey , Richardson Christopher S. , Robino Facundo , Rocha Daniel G. , Rocha Fabiana Lopes , Rodrigues Flávio Henrique Guimarães , Rohnke Adam T. , Ryan Travis J. , Salsbury Carmen M. , Sander Heather A. , da Cruz Santos-Cavalcante Nadia Maria , Sekercioglu Cagan H. , Seryodkin Ivan , Setiawan Dede Hendra , Shadloo Shabnam , Shahhosseini Mahsa , Shannon Graeme , Shier Catherine J. , Smith G. Bradley , Snyder Tom , Sollmann Rahel , Sparks Kimberly L. , Sribuarod Kriangsak , St. Clair Colleen C. , Stankowich Theodore , Steinmetz Robert , Stevenson Cassondra J. , Sunarto Sunarto  , Surasinghe Thilina D. , Sutyrina Svetlana V. , Swaisgood Ronald R. , Taktehrani Atie , Thapa Kanchan , Thorton Matthew , Tilker Andrew , Tobler Mathias W. , Tran Van Bang , Tucker Jody , Van Horn Russell C. , Vargas-Soto Juan S. , Velásquez-C Karen L. , Venter Jan , Venticinque Eduardo M. , Verschueren Stijn , Wampole Erin , Watchorn Darcy J , Wearn Oliver R. , Weiss Katherine C.B. , Welschen Alejandro , Widodo Febri Anggriawan , Williamson Jacque , Wilting Andreas , Wittemyer George , Zavaleta Arturo , Zellmer Amanda J. , Gerber Brian D. 
Published: February 2025

Circadian rhythms are a mechanism by which species adapt to environmental variability and fundamental to understanding species behavior. However, we lack data and a standardized framework to accurately assess and compare temporal activity for species during rapid ecological change. Through a global network representing 38 countries, we leveraged 8.9 million mammalian observations to create a library of 14,587 standardized diel activity estimates for 445 species. We found that less than half the species’ estimates were in agreement with diel classifications from the reference literature and that species commonly used more than one diel classification. Species diel activity was highly plastic when exposed to anthropogenic change. Furthermore, body size and distributional extent were strongly associated with whether a species is diurnal or nocturnal. Our findings provide essential knowledge of species behavior in an era of rapid global change and suggest the need for a new, quantitative framework that defines diel activity logically and consistently while capturing species plasticity.