Bearded seals are promiscuous, having more than one mate during the breeding season. Males leave after mating, providing no care to pups. Due to their solitary nature, bearded seals do not establish long-term bonds with mating partners. Occasionally, males fight over a female mate. Male bearded seals also sing, which may be a courtship routine and/or a territorial warning during the breading season.
Mating System: polygynandrous (promiscuous)
Bearded seals breed once a year, though this varies with seasonal ocean productivity. They mate between March and June, and males are at peak potency during May. Due to delayed implantation and a long gestation period (11 months), female bearded seals do not give birth until the following summer. During gestation, females gain weight to build up a supply of milk. Females give birth on pack ice between mid-March and May. Unlike their close relative, ringed seals, bearded seals do not use or assemble subnivean birth lairs. Bearded seals give birth to 1 pup, which weighs approximately 34 kg at birth. Within several days, pups enter the water. Weaning occurs in 18 to 24 days, and pups weaned by late summer have ample time to create blubber before the winter. Females reach sexual maturity at 3 to 8 years of age and males at 6 to 7 years.
Breeding interval: Bearded seals breeds approximately once a year.
Breeding season: Bearded seals breeds in March through June.
Average number of offspring: 1.
Average gestation period: 11 months.
Average birth mass: 34 kg.
Range weaning age: 18 to 24 days.
Range age at sexual or reproductive maturity (female): 3 to 8 years.
Range age at sexual or reproductive maturity (male): 6 to 7 years.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous ; delayed implantation
Average birth mass: 35000 g.
Average gestation period: 259 days.
Average number of offspring: 1.
Male bearded seals leave females after mating and provide no parental care to pups. Like many arctic seals, female bearded seals give birth to their pups on ice floes. Unlike their close relative ringed seals, however, they do not use or assemble subnivean birth lairs. While weaning her pup, a mother does not leave the ice flow. She does not eat until her pup is weaned and can be left alone.
Parental Investment: female parental care ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
- Gjertz, I., K. Kovacs, C. Lydersen, Ø. Wiig. 2000. Movements and diving of bearded seal (Erignathus barbatus) mothers and pups during lactation and post-weaning. Polar Biology, 23.8: 559-566.
- Kirlin, M. 2005. "The Bearded Seal - Mating System" (On-line). Accessed May 08, 2010 at http://www.bio.davidson.edu/people/vecase/Behavior/Spring2005/Kirlin/Mating.html.
- Kovacs, K., C. Lydersen, I. Gjertz. 1996. Birth-Site Characteristics and Prenatal Molting in Bearded Seals (Erignathus barbatus)”. Journal of Mammology, 77.4: 1085-1091.
- Kovacs, K., D. Lavigne. 1986. Maternal Investment and Neonatal Growth in Phocid Seals. Journal of Animal Ecology, 55.3: 1035-1051.
- Nelson, M. 2008. "Bearded Seal" (On-line). ADF&G Wildlife Notebook Series. Accessed May 01, 2010 at http://www.adfg.alaska.gov/index.cfm?adfg=beardedseal.main.
- Reeves, R., B. Stewart, S. Leatherwood. 1992. The Sierra Club Handbook of Seals and Sirenians. San Francisco, CA: Sierra Club Books.