Dizygotic twinning in the Hawaiian monk seal

作者：Schultz Jennifer K^*; Becker Brenda L; Johanos Thea C; Lopez Jessica U; Kashinsky Lizabeth

来源：Journal of Mammalogy, 2011, 92(2): 336-341.

DOI：10.1644/10-MAMM-A-275.1

• fecundity
• maternal investment
• microsatellite
• multiple maternity
• Monachus schauinslandi

Twinning is extremely rare in pinnipeds. Instances in which a female is observed simultaneously nursing 2 pups may represent alloparenting, or nonfilial nursing, a relatively common trait in pinnipeds. We explored the incidence of twinning in the Hawaiian monk seal (Monachus schauinslandi). We observed 7 sets of putative twins (i.e., an isolated female nursing 2 newborn pups) of 4,965 total births recorded between 1983 and 2008 (minimum twinning rate = 0.1%). Genetic specimens from the mother and both pups were available only for 5 of the 7 sets. Microsatellite genotyping revealed all of these to be dizygotic twins, with low probability of false assignment (P < 0.001). On average, Hawaiian monk seal twins were less likely to survive to weaning than singletons born in the same year and on the same island (P = 0.008). Those that weaned were smaller in size (i.e., axillary girths 1-4 SDs lower than singletons). In the critically endangered Hawaiian monk seal twinning appears to be a rare trait that results in overall lower survival rates but also offers a small opportunity for stock enhancement.

• 出版日期2011-4-15