Degus recognize but do not prefer familiar peers.

•During a 3-h partner preference test, degus were equally likely to spend time with a stranger as with a cagemate partner.•Female degus, unlike other rodents tested in the same protocol, often huddled with same-sex strangers for extended periods.•Stranger degus were more physically interactive than cagemate partners, and showed more agonistic behaviors.•Patterns of preference behavior were highly variable, with some individuals alternating frequently and others rarely.