Mexican prairie dogs are polygynous and commonly form groups of females that reside within their mother's territory resulting in large clans or colonies (i.e., matrilocal harems). Males give out a mating call that resembles an alarm call. If a female wishes to mate, it permits the approach of a sexually active male. Breeding takes place underground, and therefore little is known of copulation behavior in this species.
Mating System: polygynous
Mexican prairie dogs reproduce once per year, with litter sizes ranging from 1 to 6 pups and an average of 4. Gestation lasts 30 days, from early March to early April, after which altricial young are born pink, hairless, and blind. Skin pigmentation occurs after 12 days, and hair begins to develop after approximately 2 weeks. Young have full pelage by 3 to 4 weeks and their eyes open around 4 to 5 weeks after birth. Neonates weigh between 15 and 20 g, and the mean mass of juveniles upon emergence from their burrow varies inversely with litter size. Males are slightly heavier than females upon emergence, corresponding with the adult sexual dimorphism of the species. Juveniles reach adult weight at approximately 6 months of age. Pups are nursed for 40 to 50 days, and weaning typically occurs around 45 to 50 days after birth. Females have 8 mammae, unlike some Cynomys species, which have 10 (e.g., white-tailed prairie dog). Teats become elongate and swollen during late pregnancy and remain so until weaning is complete. Juveniles remain underground for 5 to 6 weeks, after which they emerge independent of parental care.
Both males and females may begin mating before one-year-old, however males typically wait until two years of age. Breeding season usually begins at the end of January and can extend into March, lasting about 90 days. Males begin producing sperm in December, just prior to the onset of breeding season, and discontinue sperm production in April. Males have a baculum, a penis bone found in most mammals that aids in intercourse, that averages 4.92 mm. The baculum is narrow at the base and broad at the distal end, which has 5 to 8 spines. Females become sexually active when their vulva becomes swollen and white. Estrus is very short, averaging 1 day in early March. Estrus of all females in a colony is asynchronous, which helps decrease intracolony competition for mates. Breeding season in Mexican prairie dogs is longer than in most other Cynomys species due to the climatic conditions of the Mexican Plateau where they are found. Decreased seasonality at lower latitudes allows for a longer breeding season, however, the the quality and abundance of food exhibits marginal variation between seasons.
Breeding interval: Mexican prairie dogs reproduce only once per year
Breeding season: Breeding season begins in January and ends in March
Range number of offspring: 1 to 6.
Average number of offspring: 4.
Average gestation period: 30 days.
Range weaning age: 40 to 50 days.
Range time to independence: 5 to 6 weeks.
Average age at sexual or reproductive maturity (female): 1 years.
Average age at sexual or reproductive maturity (male): 2 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Although responsibilities differ, both genders provide care to their young. Male and female Mexican prairie dogs allogroom, play with young, maintain burrows, and nest-build. Males are primarily responsible for territorial defense. Females nurse young for 40 to 50 days and weaning occurs at 45 to 50 days after birth. Juveniles remain underground for 5 to 6 weeks, after which they are fully independent and emerge from their burrows. Although infanticide is known to occur in white-tailed prairie dogs and Utah prairie dogs, there have been no known reports of infanticide occuring in Mexican prairie dogs.
Parental Investment: altricial ; male parental care ; female parental care ; pre-hatching/birth (Provisioning: Female); pre-weaning/fledging (Provisioning: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female)