Red-Pelaged Harbor Seals of the San Francisco Bay Region
Harbor seals of San Francisco Bay, California, have a higher incidence of red pelage (range, 4-32% of the total count) than is observed along the outer eastern-Pacific coast or elsewhere in the world. Red pelage was observed among all sex and age classes, except for pups. The pattern of red coloration on the body varied; most seals had red hair extending from the head down to the shoulder. Elemental analyses of hair samples revealed that red coloration was from deposition of iron oxide precipitates on the hair shaft. We postulate that the particular conditions within San Francisco Bay, including large areas of shallow water and strong summer winds with resuspension of sediments, bring sufficient quantities of ferrous iron from the sediments into the water column where it may serve as a principal source of the ferric oxide deposited on pelage of seals.
Journal of Mammalogy
Allen, S. G.,
Risebrough, R. W.,
(1993). Red-Pelaged Harbor Seals of the San Francisco Bay Region. Journal of Mammalogy, 74(3), 588-593.
Available at: https://aquila.usm.edu/fac_pubs/6643