IT'S DRAMA IN THE GRASSLAND. The mating season is always an exciting time in a prairie dog colony. Males run themselves ragged securing mates and enforcing territorial boundaries, often fighting violently with each other; and females must capitalize on a single day of estrus (sexual receptivity) for the entire year. As many as 65% of females may mate with multiple males in any given year (MATING SYSTEM). Called polyandry, this mating strategy has been correlated with higher fecundity (reproduction), genetically diverse offspring, and healthier juveniles.
This year so far we have had more females than expected who have mated with only one male, while others have predictably taken advantage of the males available. One of our females even copulated with four males on her day of estrus. As you can probably imagine, the mating season is full of dramatic courtships, disputes, fights, mating calls, and mostly underground copulations.
Coyotes, badgers, golden eagles, and other predators (THE PREY ANIMAL) have been sighted since the start of spring emergences (coming out of hibernation), and their appearances demonstrate the risk these prairie dogs take when they become distracted by mating activities.
As for John and the Prairie Dog Squad, the mating season means long, busy hours taking data on multiple copulations in a single day. Yesterday we had 11 females go into estrus at our study colony! Estrous females and dominant males stay up late into the night on the day they copulate, taking advantage of the absolute last glow of dusk to forage and find mating partners. This further puts the prairie dogs in danger, as dusk is a favorite hunting time for coyotes and badgers, and prairie dogs have poor eyesight in dim lighting.
We still have up to two weeks remaining of the mating season, and so far more than 30 of our marked females have gone into estrus. While an occasional female is still waking up late from hibernation, we are expecting close to 20 more to go into estrus over the next several days. That’s a lot of action, a lot of data, a lot of ultrasounds in April/May, and a lot of juveniles to expect come June!