Aquatic thermoregulation in the muskrat (<i>Ondatra zibethicus</i>): energy demands of swimming and diving

MacArthur, Robert A.

doi:10.1139/z84-040

Cited by 42 publications

(45 citation statements)

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“…As revealed in Fig. 3, net Tb decline increases with cumulative dive time in muskrats, an observation we attribute to the enhanced convective heat loss associated with wholebody submersion (MacArthur 1984).…”

Section: Discussionmentioning

confidence: 57%

“…A positive-pressure, open-circuit system similar to that described by MacArthur (1984) was used, in which inlet flow rate was maintained at 4.5 1.min -x with a Matheson rotameter calibrated against a model 1057 Brooks Vol-U-Meter. Exhaust gas from the chamber was split into two streams.…”

Section: Animalsmentioning

confidence: 99%

“…An excellent model for investigating this problem is provided by the muskrat, Ondatra zibethicus. Holarctic in distribution, these amphibious rodents are surprisingly prone to immersion hypothermia (Hart 1962;MacArthur 1979aMacArthur , 1984. Even brief episodes of swimming in cold water are sufficient to elicit pronounced abdominal cooling and a threefold rise in MR of O. zibethicus (MacArthur 1984).…”

Section: Introductionmentioning

confidence: 99%

“…Holarctic in distribution, these amphibious rodents are surprisingly prone to immersion hypothermia (Hart 1962;MacArthur 1979aMacArthur , 1984. Even brief episodes of swimming in cold water are sufficient to elicit pronounced abdominal cooling and a threefold rise in MR of O. zibethicus (MacArthur 1984). Earlier studies have underscored the value of stored body heat to aquatic endurance in muskrats, and revealed the extent to which these rodents depend upon behavioral mechanism to regulate Tb in nature (MacArthur 1979a(MacArthur , 1984.…”

Section: Introductionmentioning

confidence: 99%

“…Even brief episodes of swimming in cold water are sufficient to elicit pronounced abdominal cooling and a threefold rise in MR of O. zibethicus (MacArthur 1984). Earlier studies have underscored the value of stored body heat to aquatic endurance in muskrats, and revealed the extent to which these rodents depend upon behavioral mechanism to regulate Tb in nature (MacArthur 1979a(MacArthur , 1984. However, it is conceivable that muskrats might also utilize HIF to attenuate, if not avoid, immersion hypothermia.…”

Section: Introductionmentioning

confidence: 99%

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Heat increment of feeding and its thermoregulatory benefit in the muskrat (Ondatra zibethicus)

MacArthur

Campbell

1994

J Comp Physiol B

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Abstract. The calorigenic effect of feeding and its potential benefit in defraying thermoregulatory costs and attenuating immersion hypothermia of adult muskrats were investigated. A single session of feeding on aquatic vegetation was sufficient to raise the metabolic rate of muskrats for a period of at least 5 h. The peak postprandial rate of oxygen consumption averaged 1.42 times the level established for fasted animals, and the heat increment of feeding accounted for about 40% of the metabolizable energy intake of muskrats. There was noevidence of a postprandial rise in oxygen consumption of muskrats that entered water at 18-19 ~ after feeding. In aquatic trials, average and minimum steady-state oxygen consumption rates of fed muskrats were similar to, or even lower than values recorded from fasted animals, implying substitution of heat increment of feeding for thermoregulatory heat production. Our data did not support the hypothesis that heat increment of feeding retards body cooling in water. Net body temperature decline in water was actually higher in fed animals than in fasted controls. However, since previously fed muskrats also entered water at an elevated body temperature, the final body temperature (at 30 min immersion) was similar in all groups. These findings suggest that metabolic heat generated incidental to preimmersion feeding could provide a thermoregulatory benefit to muskrats by reducing the need for active thermogenesis in water.

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Section: Discussionmentioning

confidence: 57%

Section: Animalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Heat increment of feeding and its thermoregulatory benefit in the muskrat (Ondatra zibethicus)

MacArthur

Campbell

1994

J Comp Physiol B

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Diving behavior in a free‐living, semi‐aquatic herbivore, the Eurasian beaver Castor fiber

Graf

Wilson

Sanchez

et al. 2017

Ecology and Evolution

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Semi‐aquatic mammals have secondarily returned to the aquatic environment, although they spend a major part of their life operating in air. Moving both on land, as well as in, and under water is challenging because such species are considered to be imperfectly adapted to both environments. We deployed accelerometers combined with a depth sensor to study the diving behavior of 12 free‐living Eurasian beavers Castor fiber in southeast Norway between 2009 and 2011 to examine the extent to which beavers conformed with mass‐dependent dive capacities, expecting them to be poorer than wholly aquatic species. Dives were generally shallow (<1 m) and of short duration (<30 s), suggesting that the majority of dives were aerobic. Dive parameters such as maximum diving depth, dive duration, and bottom phase duration were related to the effort during different dive phases and the maximum depth reached. During the descent, mean vectorial dynamic body acceleration (VeDBA—a proxy for movement power) was highest near the surface, probably due to increased upthrust linked to fur‐ and lung‐associated air. Inconsistently though, mean VeDBA underwater was highest during the ascent when this air would be expected to help drive the animals back to the surface. Higher movement costs during ascents may arise from transporting materials up, the air bubbling out of the fur, and/or the animals’ exhaling during the bottom phase of the dive. In a manner similar to other homeotherms, beavers extended both dive and bottom phase durations with diving depth. Deeper dives tended to have a longer bottom phase, although its duration was shortened with increased VeDBA during the bottom phase. Water temperature did not affect diving behavior. Overall, the beavers’ dive profile (depth, duration) was similar to other semi‐aquatic freshwater divers. However, beavers dived for only 2.8% of their active time, presumably because they do not rely on diving for food acquisition.

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Aquatic Mammals in Cold

MacArthur

1989

Advances in Comparative and Environmental Physiology

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Aquatic thermoregulation in the muskrat (Ondatra zibethicus): energy demands of swimming and diving

Cited by 42 publications

References 0 publications

Heat increment of feeding and its thermoregulatory benefit in the muskrat (Ondatra zibethicus)

Heat increment of feeding and its thermoregulatory benefit in the muskrat (Ondatra zibethicus)

Diving behavior in a free‐living, semi‐aquatic herbivore, the Eurasian beaver Castor fiber

Aquatic Mammals in Cold

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