title: First evidence of gregarious denning in opossums (Didelphimorphia, Didelphidae), with notes on their social behaviour.
abstract: The Didelphidae are considered solitary opossums with few social interactions, usually limited to mating-related or mother-pouch young interactions. Anecdotal reports suggest that additional interactions occur, including den sharing by a few individuals, usually siblings. Here, we report novel observations that indicate opossums are more social than previously thought. These include nest sharing by males and females of Marmosa paraguayana, Gracilinanus microtarsus and Marmosops incanus prior to the onset of the breeding season and without signs of sexual activity; this is taken to indicate early pair-bonding matching and cooperative nest building. We also recorded den sharing among recently weaned siblings of Didelphis aurita and Caluromys philander. In addition, we observed 13 individuals of Didelphis albiventris representing three age classes resting without agonistic interactions in a communal den. These are the first reports of gregarious behaviour involving so many individuals, which are either unrelated or represent siblings from at least two litters, already weaned, sharing the same den with three adults. Sociality in opossums is probably more complex than previously established, and field experimental designs combining the use of artificial nests with camera traps or telemetry may help to gauge the frequency and extent of these phenomena.
authors.affiliation: Laboratório de Mastozoologia, Departamento de Zoologia, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego, s/n. Cidade Universitária, Recife, PE 50670-901, Brazil diegoastua@ufpe.br.
authors.forename: Diego
authors.identifier: http://orcid.org/0000-0002-9573-6437
authors.initials: D
authors.lastname: Astúa
authors.affiliation: Laboratório de Mastozoologia, Departamento de Zoologia, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego, s/n. Cidade Universitária, Recife, PE 50670-901, Brazil.
authors.forename: Rafael A
authors.initials: RA
authors.lastname: Carvalho
authors.affiliation: Laboratório de Mastozoologia, Departamento de Zoologia, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego, s/n. Cidade Universitária, Recife, PE 50670-901, Brazil.
authors.forename: Paula F
authors.initials: PF
authors.lastname: Maia
authors.affiliation: Laboratório de Mamíferos, Departamento de Ecologia e Sistemática, Universidade Federal da Paraíba, Castelo Branco s/n, João Pessoa, PB 58059-900, Brazil.
authors.forename: Arthur R
authors.initials: AR
authors.lastname: Magalhães
authors.affiliation: Laboratório de Biologia e Parasitologia de Mamíferos Silvestres Reservatórios, Pavilhão Lauro Travassos, IOC/Fundação Oswaldo Cruz, Av. Brasil 4365, Rio de Janeiro, RJ 21040-360, Brazil.
authors.forename: Diogo
authors.identifier: http://orcid.org/0000-0002-9464-6712
authors.initials: D
authors.lastname: Loretto
mesh_terms: D000818:Animals; D001938:Brazil; D005260:Female; D008297:Male; D009893:Opossums / Q000502:physiology*; D012890:Sleep; D012919:Social Behavior; D013045:Species Specificity
keywords: Didelphidae; breeding; cooperation; den sharing; opossums; sociality