In "Predicting Reproduction in Captive Sea Otters," published in the journal Zoo Biology in 2005, gestation lengths for an otter named Mali who became pregnant four times from 1998 to 2001 are listed: 220 days, 255 days, 249 days, and 188 days.7 Explain why these lengths should not be used to estimate the mean gestation length of all captive sea otters.