Disruption of pair bonding induces pregnancy failure in newly mated mongolian gerbils (Meriones unguiculatus).

The efficacy of several exteroceptive factors including exposure to a 'strange' male, were tested to induce pregnancy failure in newly mated Mongolian gerbils. Only physical separation of monogamous pairs consistently induced pregnancy failure. This phenomenon was restricted to the immediate period after mating and is believed to be due to disruption of pair bonding, with associated luteal and implantation failure. Concurrent lactation annulled this effect.