Noninvasive reproductive steroid hormone estimates from fecal samples of captive female sea otters (Enhydra lutris).

Noninvasive methods were validated for monitoring fecal metabolites of reproductive hormones (total estrogens and progestagens) in sea otters. Several captive female sea otters were sampled an average of two to three times per week over at least 1 year to document the reproductive hormone levels within each major reproductive event (estrus, anestrus, luteal phase, and pregnancy). We report significant differences in reproductive hormone levels consistent with most reproductive categories, as well as the minimal number of consecutive samples needed to accurately determine pregnancy using these methods.