OXT and Anxiety: Given the well-known role of OXT in facilitating pro-social behaviors (Williams et al., 1992; Feldman et al., 2007; Kojima and Alberts, 2011; Feldman, 2012) and reducing anxiety-like behaviors (Windle et al., 1997; Ring et al., 2006; Blume et al., 2008), we expected to find a facilitating effect of OXT on social play, especially in the novel cage.