Coat is lost through molting once per year, usually between April and December. Molting takes approximately 9-10 days. Seals remain on shore during most of the molting period. In 1998, about 1200-1300 in total population. About 56 individuals reside at Midway Atoll.
Most seals remain at their birth atoll for life and there is little permanent inter-atoll movement.
About 22 monk seals visit Midway intermittantly from Pearl and Hermes, and Kure Atoll. Monk seal population currently being studied by Hawaii Wildlife Fund, and National Marine Fisheries Service researchers. 500 m. Resting takes place on isolated and undisturbed beaches. Breeding Sexually mature at age 4-7 years. Females begin breeding at 5-6 years.