Males attract females with secretions from their enlarged dermal gland during the mating season.
Mating System: polygynous
Males and females of this species remain together throughout the year, including the period when young are produced. Mating occurs in early spring when the dermal gland of adult males is most functional and the testes enlarge and descend. Normally only one young is produced per pregnancy, with twins being very rare. Eumops perotis is a eutherian with a gestation period of approximately 80 to 90 days. The offspring are dull black in color at birth and are naked, except for tactile hairs on the feet and face. The period of parturition usually extends from June into July, varying more than for any other bat in the United States. A nursery colony of these bats may contain young ranging from newborn individuals to ones already several weeks old. Nursery roosts are located in tight rock crevices or holes in buildings at least 90 cm deep and 5 cm wide (Texas Tech, 1997; Ahlborn, 2000).
Breeding season: March to July
Range number of offspring: 1 to 2.
Average number of offspring: 1.
Range gestation period: 80 to 90 days.
Range weaning age: 1 to 2 months.
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); viviparous
Males remain with females during the period when young are produced but it is uncertain what degree of assistance in care they actually provide.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)