Table 1.
Comparison of diving characteristics in muskrats and rats.
| Parameter | Muskrat | Rat |
|---|---|---|
| WEIGHT | ||
| Adult male (g) | 1217 ± 124 (Doyle et al., 1988) | 300–400 (Baker et al., 2006) |
| Adult female (g) | 1008 ± 121 (Doyle et al., 1988) | 250–300 (Baker et al., 2006) |
| HEART RATE | ||
| Resting (BPM) | 241 ± 16 (McCulloch and Jones, 1990) | 405 ± 4 (McCulloch et al., 2010) |
| Disturbed (BPM) | 259 ± 13 (McCulloch and Jones, 1990) | 453 ± 5 (McCulloch et al., 2010) |
| Diving, voluntary | ||
| Pre-dive (BPM) | 297 ± 13 (McCulloch and Jones, 1990) | 453 ± 12 (McCulloch et al., 2010) |
| Dive (BPM) | 130 ± 9 (McCulloch and Jones, 1990) | 101 ± 8 (McCulloch et al., 2010) |
| SWIMMING SPEED (in lab) | ||
| Surface (m/s) | 0.2–0.75† (Fish, 1984) | 0.22 ± 0.01 (McCulloch, unpublished) |
| Underwater (m/s) | 0.45 ± 0.04 (MacArthur, 1992) | 0.36 ± 0.01 (McCulloch, unpublished) |
| LUNG | ||
| Oxygen storage capacity (ml O2/kg) | 6.4* (MacArthur, 1990) | |
| BLOOD | ||
| Hematocrit (%) | 40.5 ± 1.7 (Snyder, 1983) | 40.8 ± 1.1 (Snyder, 1983) |
| Hemoglobin (g/100 ml blood) | 13.0 ± 0.4 (Snyder, 1983) | 14.4 ± 0.4 (Snyder, 1983) |
| P50 (40 mmHg) | 27.7 ± 1.1 (MacArthur, 1984c) | 35.5 ± 0.9 (MacArthur, 1984c) |
| Volume (ml/100 g) | 9.7 ± 0.3* (MacArthur et al., 2001) | 6.4 (Baker et al., 2006) |
| Oxygen storage capacity (ml O2/kg) | 14.4* (MacArthur, 1990) | |
| MUSCLE MYOGLOBIN | ||
| Heart (mg/g tissue) | 7.4 ± 0.1 (Snyder, 1983) | 5.4 ± 0.5 (Snyder, 1983) |
| Skeletal (gastrocnemius; mg/g tissue) | 13.3 ± 0.5 (Snyder, 1983) | 1.6 ± 0.3 (Snyder, 1983) |
| Oxygen storage capacity (ml O2/kg) | 4.4* (MacArthur, 1990) | |
| DIVING | ||
| Resting oxygen consumption in air (ml O2/g/h) | 0.78 ± 0.01 (MacArthur and Krause, 1989) | 0.87 (Schmidt-Nielsen, 1983) |
| Diving oxygen consumption (ml O2/g/h) | 2.22 (MacArthur and Krause, 1989) | |
| Total body oxygen storage capacity (ml O2/kg) | 25.2* (MacArthur, 1990) | |
| Aerobic dive limit (s) | 40.9* (MacArthur, 1990) | |
| Maximum submersion duration (forced dive, min) | 12 (Irving, 1939) | 2 (Irving, 1939) |
†Against current in swim flume; *summer-acclimatized adult muskrats.