THE MATING SEASON has officially begun here at our study colony at the Valles Caldera National Preserve, New Mexico.

Every year the mating season follows close behind snowmelt. As female Gunnison's prairie dogs gradually come aboveground in the spring, attentive males will immediately begin to sniff between females' hind legs to check for estrus. They will follow the females every day, hoping to be the first to mate.

During the mating season, conflict among males can be gladiatorial. The stakes are high: with only one day of sexual receptivity the entire year, and only a few hours of that day, females in estrus are like holy grails in the meadow. Prairie dogs are polygynous (in that a single male will mate with multiple females) but are also commonly polyandrous (in that a single female will mate with multiple males). It is in the female's interest to mate with as many males as she can, but it's in the male's interest to be the exclusive inseminator. This conflict of intentions makes for high drama as the receptive female, after copulating with her first male, will attempt to slip away and find a new mate, while the first male anxiously attempts to keep constant watch over her, often driving her into her burrow to keep her in place, whilst fighting off unrelenting contenders.

Before the day ends, many prairie dog females will indeed have mated with multiple males, and so it becomes evident not only how strong the instinct for the estrous female, but how challenging the task for the possessive male. Male prairie dogs will run themselves ragged during the mating season, becoming so undernourished and taking so many blows that injuries are inevitable, and sometimes even exile or death could befall the overpowered.