Table 1.
Handling efficiency (amount of time required to handle and consume one prey item) of sea otters at CC that specialize on nine different prey types, contrasted with the handling efficiency of nonspecialists
| Prey type | Prey diameter, cm | Specialists, mean per-item handling time (SD), s | n | Nonspecialists, mean per-item handling time (SD), s | n | % increase in efficiency | Student's t value | P |
|---|---|---|---|---|---|---|---|---|
| Marine snails | 1–5 | 9.41 (1.578) | 5 | 18.916 (8.222) | 6 | 101.0 | 2.771 | 0.036 |
| Kelp crabs | 6–10 | 84.092 (13.829) | 5 | 108.674 (40.68) | 29 | 29.2 | 2.518 | 0.021 |
| Urchins | 1–5 | 20.575 (3.933) | 6 | 25.978 (7.615) | 18 | 26.3 | 2.243 | 0.038 |
| Clams | 6–10 | 47.785 (10.208) | 5 | 67.994 (30.083) | 15 | 42.3 | 2.243 | 0.038 |
| Worms | 11–15 | 8.32 (0.601) | 4 | 11.223 (2.649) | 8 | 34.9 | 2.952 | 0.018 |
| Average % increase in efficiency for prey types with significant differences: | 46.7 | |||||||
| Cancer crabs | 11–15 | 183.217 (75.074) | 5 | 188.323 (91.386) | 25 | 2.8 | 0.134 | 0.898 |
| Abalone | 11–15 | 166.667 (43.501) | 3 | 111.75 (24.865) | 4 | −33.0 | 1.96 | 0.145 |
| Sea stars | 11–15 | 44.606 (8.685) | 5 | 58.521 (40.432) | 18 | 31.2 | 1.352 | 0.191 |
| Mussels | 1–5 | 24.968 (4.167) | 5 | 22.493 (6.042) | 11 | −9.9 | 0.95 | 0.362 |
| Average % increase in efficiency for prey types without significant differences: | −2.2 | |||||||
| Average % increase in efficiency for all prey types: | 25.0 | |||||||
Handling time data were filtered to include only the most commonly captured size class for each prey type. Sample sizes (n) indicate the number of animals classified as specialists and nonspecialists, respectively (the mean handling time for a given prey type by one animal represents the sample unit for statistical comparison). The relative difference between specialists and nonspecialists is presented as the percent increase in handling efficiency for specialists (number of items handled per unit time), followed by the statistical significance (based on a two-tailed t test) of this difference.