Reproductive activity in the brown bullhead begins in May and spawning occurs in late May and early June at Munro Lake, Michigan. Most oviposition occurs during a 10- to 15-day period each year. Adults care for eggs (embryos), larvae and juveniles as long as 20 days after oviposition. Males and females breed with only one mate in each season. Care-giving involves nest-building prior to oviposition, and then guarding embryos, larvae and juveniles. In addition, embryos and larvae are fanned and manipulated by the parents at the nest site. Males alone give parental care more frequently than do females alone. When both sexes attend a brood, males spend more time with the brood and more time in close proximity to the offspring than do females. For these reasons, males can be viewed as the principal care-givers. Male parental care occurs throughout the Ictaluridae and biparental care is common in the genus Ictalurus.