Parents sometimes discriminate offspring from non-offspring while responding to vocalizations, ensuring that parental care is directed towards their progeny exclusively. This discrimination may result from differences in acoustic characteristics across individuals. However, recognition capabilities specific to individuals may not occur when parents differentiate offspring via location because litters are segregated spatially. Offspring discrimination is important during “distress calls” emitted by young-of-the-year for imminent danger because mothers that respond to non-offspring reduce the time available for protecting their litter, and failure to respond may result in offspring mortality. Columbian ground squirrel (Spermophilus columbianus) pups sometimes emit a scream-like distress call near their mothers when attacked by marauding conspecifics. With field observations of infanticide and playback experiments that manipulated the identity and location of the caller, I examined whether a location-based rule or vocal recognition per se mediate female responses to distress calls. Mothers became vigilant and approached the speaker in response to playbacks of distress calls broadcast on their territory, regardless of whether the recording was an offspring or non-offspring. However, mothers approached distress call recordings originating on their territory more often than those occurring on adjacent territories. Thus, female Columbian ground squirrels respond to distress calls based on a location-based rule (viz., on or off their territory) rather than true vocal recognition. This strategy seems appropriate, since lactating females are territorial and pups rarely mix between litters during the 1–5 day period just after emergence from their natal burrow when they are susceptible to infanticide.