Table 2.
Characteristics of “in water” and “on land” periods in four walruses.
| Parameter | W1 | W2 | W3 | W4 |
|---|---|---|---|---|
| Duration of observations (days) | 9 | 7 | 12 | 6 |
| “In water” period | ||||
| Total number of periods | 5 | 6 | 4 | 4 |
| Mean duration (h) | 27.2 ± 7.7 | 17.7 ± 5.3 | 55.5 ± 18.2 | 29.8 ± 5.4 |
| Duration range (min-max, h) | 12–54 | 6–36 | 3–84 | 18–43 |
| aThe longest episode of uninterrupted swimming (h) | 23 | 8 | 17 | 9 |
| Time spent in water (% of 1 h) | 91.4 ± 1.5 | 90.1 ± 1.1 | 93.3 ± 0.6 | 95.1 ± 1.1 |
| AW in water (% of 1 h) | 80.7 ± 4.1 | 81.8 ± 4.9 | 91.9 ± 0.8 | 94.2 ± 1.1 |
| AW in water (% of time in water) | 88.2 | 90.8 | 98.4 | 99.0 |
| Behavioral sleep (% of 1 h) | 10.1 ± 2.9 | 7.2 ± 3.5 | 1.2 ± 0.9 | 0 |
| “On land” period | ||||
| Total number of periods | 6 | 5 | 5 | 3 |
| Mean duration (h) | 9.8 ± 2.0 | 8.8 ± 1.9 | 12.4 ± 2.5 | 8.3 ± 3.8 |
| Duration range (min-max, h) | 2–14 | 3–11 | 6–19 | 4–16 |
| Time on land (% of 1 h) | 96.3 ± 0.7 | 88.1 ± 3.4 | 96.0 ± 2.3 | 98.4 ± 1.0 |
| AW on land (% of 1 h) | 15.5 ± 3.4 | 21.0 ± 3.7 | 6.7 ± 1.4 | 7.4 ± 3.2 |
| Behavioral sleep (% of 1 h) | 50.0 ± 5.7 | 43.0 ± 4.4 | 71.6 ± 5.3 | 38.0 ± 6.7 |
| Behavioral sleep (% of time on land) | 51.9 ± 3.4 | 48.5 ± 3.8 | 73.8 ± 4.9 | 39.5 ± 6.6 |
The data are presented as mean ± S.E.M. AW: active wakefulness.
a
The 98% criterion was applied to determine these values (or 59 min per 1 h).