Water conservation in fasting northern elephant seals (<i>Mirounga angustirostris</i>)

Lester, Christopher W.; Costa, Daniel P.

doi:10.1242/jeb.02503

Cited by 36 publications

(28 citation statements)

References 71 publications

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“…) (Lester and Costa, 2006). Oxygen consumption was calculated using eqn4B from Withers (Withers, 1977) and a respiratory quotient of 0.83 for herbivores (Schmidt-Nielsen, 1997).…”

Section: Heat Production and Respiratory Evaporative Water Lossmentioning

confidence: 99%

Climate influences thermal balance and water use in African and Asian elephants: physiology can predict drivers of elephant distribution

Dunkin

Wilson²,

Way³

et al. 2013

Journal of Experimental Biology

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SUMMARYElephant movement patterns in relation to surface water demonstrate that they are a water-dependent species. Thus, there has been interest in using surface water management to mitigate problems associated with localized elephant overabundance. However, the physiological mechanisms underlying the elephant's water dependence remain unclear. Although thermoregulation is likely an important driver, the relationship between thermoregulation, water use and climate has not been quantified. We measured skin surface temperature of and cutaneous water loss from 13 elephants (seven African, 3768±642kg; six Asian, 3834±498kg) and determined the contribution of evaporative cooling to their thermal and water budgets across a range of air temperatures (8-33°C). We also measured respiratory evaporative water loss and resting metabolic heat production on a subset of elephants (N=7). The rate of cutaneous evaporative water loss ranged between 0.31 and 8.9gmin m −2 for African elephants. Simulated thermal and water budgets using climate data from Port Elizabeth, South Africa, and Okaukuejo, Namibia, suggested that the 24-h evaporative cooling water debt incurred in warm climates can be more than 4.5 times that incurred in mesic climates. This study confirms elephants are obligate evaporative coolers but suggests that classification of elephants as water dependent is insufficient given the importance of climate in determining the magnitude of this dependence. These data highlight the potential for a physiological modeling approach to predicting the utility of surface water management for specific populations. Supplementary material available online at

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“…) (Lester and Costa, 2006). Oxygen consumption was calculated using eqn4B from Withers (Withers, 1977) and a respiratory quotient of 0.83 for herbivores (Schmidt-Nielsen, 1997).…”

Section: Heat Production and Respiratory Evaporative Water Lossmentioning

confidence: 99%

Climate influences thermal balance and water use in African and Asian elephants: physiology can predict drivers of elephant distribution

Dunkin

Wilson²,

Way³

et al. 2013

Journal of Experimental Biology

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“…During these fasts, they minimize respiratory evaporative water loss by using periods of apnea as well as through the action of their extensive respiratory turbinates. With 90% of their turbinate surface area devoted to respiration, elephant seals retain as much as 92% of the water added to each breath (Lester & Costa, 2006). This suggests that water conservation may be equally or more important than heat conservation in driving turbinate evolution in the elephant seal and other pinnipeds, with the interesting exception of the extinct tropical monk seal.…”

Section: Linearmentioning

confidence: 99%

“…We have assumed that the greater complexity and surface areas of the respiratory turbinates of aquatic species results in a more efficient transfer of water and heat, and there is some experimental evidence to suggest that is the case for the elephant seal (Lester & Costa, 2006). Similarly, we have assumed that the more extensive olfactory surface area of terrestrial species translates into improved detection of odorants.…”

Section: Linearmentioning

confidence: 99%

“…In addition, to conserve water they evolved complex, efficient kidneys and likely modified their maxilloturbinates to better retain both heat and water during lung ventilation. A dramatic expansion of the maxilloturbinates has been documented in a few studies of individual seals and sea lions based on the sectioning of fresh heads (Huntley et al 1984;Folkow et al 1988;Lester & Costa, 2006) but similar studies have not been done for other semi-aquatic arctoids, nor has the overall scaling of maxilloturbinate surface area with body size been quantified in any group of mammals. Without this, it is difficult to assess the functional and evolutionary significance of the spectacular maxilloturbinates of the few pinnipeds that have been studied.…”

Section: Introductionmentioning

confidence: 99%

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Aquatic adaptations in the nose of carnivorans: evidence from the turbinates

Valkenburgh¹,

Curtis²,

Samuels³

et al. 2011

Journal of Anatomy

111

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Inside the mammalian nose lies a labyrinth of bony plates covered in epithelium collectively known as turbinates. Respiratory turbinates lie anteriorly and aid in heat and water conservation, while more posterior olfactory turbinates function in olfaction. Previous observations on a few carnivorans revealed that aquatic species have relatively large, complex respiratory turbinates and greatly reduced olfactory turbinates compared with terrestrial species. Body heat is lost more quickly in water than air and increased respiratory surface area likely evolved to minimize heat loss. At the same time, olfactory surface area probably diminished due to a decreased reliance on olfaction when foraging under water. To explore how widespread these adaptations are, we documented scaling of respiratory and olfactory turbinate surface area with body size in a variety of terrestrial, freshwater, and marine carnivorans, including pinnipeds, mustelids, ursids, and procyonids. Surface areas were estimated from high-resolution CT scans of dry skulls, a novel approach that enabled a greater sampling of taxa than is practical with fresh heads. Total turbinate, respiratory, and olfactory surface areas correlate well with body size (r 2 ‡ 0.7), and are relatively smaller in larger species. Relative to body mass or skull length, aquatic species have significantly less olfactory surface area than terrestrial species. Furthermore, the ratio of olfactory to respiratory surface area is associated with habitat. Using phylogenetic comparative methods, we found strong support for convergence on 1 : 3 proportions in aquatic taxa and near the inverse in terrestrial taxa, indicating that aquatic mustelids and pinnipeds independently acquired similar proportions of olfactory to respiratory turbinates. Constraints on turbinate surface area in the nasal chamber may result in a trade-off between respiratory and olfactory function in aquatic mammals.

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“…Van Valkenburgh et al (2011) hypothesized that larger respiratory conchae have evolved to increase water and heat retention in response to the limited fresh water in marine environments and greater potential for heat loss underwater. The large respiratory conchae of elephant seals (Mirounga angustirostris) contribute to this species' ability to retain up to 92.5% of the water contained in each breath (Lester and Costa 2006). Although larger conchae putatively improve water conservation, they may also recapture more body heat, potentially posing a challenge for animals that inhabit hot climates, such as the dune-endemic M. m. atlantica; however, the potential of respiratory conchae to conserve heat seems to be greatest at lower ambient temperatures.…”

Section: Subspecies Comparisonsmentioning

confidence: 99%

Morphological and Histochemical Study of the Nasal Cavity and Fused Olfactory Bulb of the Brown-Eared Bulbul,Hysipetes amaurotis

et al. 2009

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Water conservation in fasting northern elephant seals (Mirounga angustirostris)

Abstract: . (1993). Water conservation and protein metabolism in northern elephant seal pups during the postweaning fast.

Cited by 36 publications

References 71 publications

Climate influences thermal balance and water use in African and Asian elephants: physiology can predict drivers of elephant distribution

Climate influences thermal balance and water use in African and Asian elephants: physiology can predict drivers of elephant distribution

Aquatic adaptations in the nose of carnivorans: evidence from the turbinates

Morphological and Histochemical Study of the Nasal Cavity and Fused Olfactory Bulb of the Brown-Eared Bulbul,Hysipetes amaurotis

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