The atmospheric environment of the fossorial mole rat (Spalax ehrenbergi): Effects of season, soil texture, rain, temperature and activity

Arieli, Ran

doi:10.1016/0300-9629(79)90197-x

Cited by 91 publications

(54 citation statements)

References 22 publications

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“…The combination of a large number of extremely social animals living in a crowded subterranean space where ventilation is poor means that naked mole-rats are exposed to chronically low levels of O 2 (and high levels of CO 2 ). Although gas concentrations have not been measured in naked mole-rat burrows in nature, in other fossorial species O 2 levels can be as low as 6-14% and CO 2 levels can be as high as 6-10% (Arieli, 1979;van Aardt et al, 2007). Because most of these measurements are for burrows of solitary animals or small colonies, levels in large colonies of naked mole-rats may reach even more extreme values.…”

Section: Buried Alive! Arrested Development and Hypoxia Tolerance In mentioning

confidence: 99%

No oxygen? No problem! Intrinsic brain tolerance to hypoxia in vertebrates

Larson

Drew

Folkow

et al. 2014

Journal of Experimental Biology

134

102

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Many vertebrates are challenged by either chronic or acute episodes of low oxygen availability in their natural environments. Brain function is especially vulnerable to the effects of hypoxia and can be irreversibly impaired by even brief periods of low oxygen supply. This review describes recent research on physiological mechanisms that have evolved in certain vertebrate species to cope with brain hypoxia. Four model systems are considered: freshwater turtles that can survive for months trapped in frozen-over lakes, arctic ground squirrels that respire at extremely low rates during winter hibernation, seals and whales that undertake breath-hold dives lasting minutes to hours, and naked mole-rats that live in crowded burrows completely underground for their entire lives. These species exhibit remarkable specializations of brain physiology that adapt them for acute or chronic episodes of hypoxia. These specializations may be reactive in nature, involving modifications to the catastrophic sequelae of oxygen deprivation that occur in non-tolerant species, or preparatory in nature, preventing the activation of those sequelae altogether. Better understanding of the mechanisms used by these hypoxiatolerant vertebrates will increase appreciation of how nervous systems are adapted for life in specific ecological niches as well as inform advances in therapy for neurological conditions such as stroke and epilepsy.KEY WORDS: Arctic ground squirrel, Cetacean, Hypoxia, Naked mole-rat, Seal, Turtle IntroductionEnvironmental conditions vary enormously for vertebrates, both with respect to the extreme conditions tolerated by a given species at different times and with respect to average living conditions tolerated by different species. Temperature is perhaps the most obvious example: from the poles to the equator, average ambient temperatures vary widely and have been accompanied by physiological adaptations appropriate to resident species; seasonal variations in temperature and resource variability can induce dramatic changes in physiological and/or behavioral patterns including migration and hibernation. Oxygen levels also vary widely, with animals adapted to sea level, high-altitude, underground and aquatic habitats. Oxygen levels can also change dramatically on a shorter-term basis, as can occur in tidal pools or in breath-hold divers. Approximately 20% of the oxygen consumed by the human body is used by the brain. The greater part of this oxygen is used to produce the ATP required to maintain the membrane potentials necessary for electrical signaling with synaptic and action potentials (Harris et al., 2012). In many vertebrates, including adult humans, interruption of the oxygen supply to the brain for more than a few minutes leads to irreversible neurological damage, including neuronal death. Without oxidative phosphorylation, ATP-dependent neuronal processes including ion transport and neurotransmitter reuptake decline sharply. Without pumping, ion gradients fail and neurons depolarize, releasing excessive levels...

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Section: Buried Alive! Arrested Development and Hypoxia Tolerance In mentioning

confidence: 99%

No oxygen? No problem! Intrinsic brain tolerance to hypoxia in vertebrates

Larson

Drew

Folkow

et al. 2014

Journal of Experimental Biology

134

102

View full text Add to dashboard Cite

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“…Animals that have adopted subterranean lifestyles typically exhibit a low resting metabolic rate (RMR) and a high thermal conductance [32], [33] and [34]. A low RMR has been suggested to be an adaptation to the hypoxic (low oxygen levels) and hypercapnic (high carbon dioxide levels) conditions encountered within sealed burrow systems [35] and [36]. Low RMR's may also represent energy saving adaptations to lessen the large energetic costs incurred during burrowing [37], [38], [39] and [34].…”

Section: Introductionmentioning

confidence: 99%

The energetics of huddling in two species of mole-rat (Rodentia: Bathyergidae)

Kotzé

Bennett

Scantlebury

2008

Physiology & Behavior

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Small rodents with a large surface-area-to-volume ratio and a high thermal conductance are likely to experience conditions where they have to expend large amounts of energy in order to maintain a constant body temperature at low ambient temperatures. The survival of small rodents is thus dependent on their ability to reduce heat loss and increase heat production at low ambient temperatures. Two such animals are the social subterranean rodents Cryptomys damarensis (the Damaraland mole-rat) and Cryptomys hottentotus natalensis (the Natal mole-rat). This study examined the energy savings associated with huddling as a behavioural thermoregulatory mechanism to conserve energy in both these species. Individual oxygen consumption (VO 2 ) was measured in groups ranging in size from one to 15 huddling animals for both species at ambient temperatures of 14, 18, 22, 26 and 30 °C. Savings in energy (VO 2 ) were then compared between the two species. Significant differences in VO 2 (p < 0.05) were found within each species, indicating that both Damaraland mole-rats and Natal mole-rats saved more energy in larger as opposed to smaller groups. VO 2 was also different between the two species, with Damaraland mole-rats showing a higher decrease in VO 2 with increasing group size compared to Natal mole-rats. These findings suggest that huddling confers significant energy savings in both species and that the amount of energy saved is related to each species' ecology. More generally, these findings suggest that group living desert-adapted species are likely to be more prone to heat loss at low ambient temperatures than temperate-adapted species, especially at low group sizes. This is presumably offset against the advantages obtained by having a low metabolic rate and avoiding hyperthermia when temperatures are hot.

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“…Arieli, 1979;Roper et al, 2001;Shams et al, 2005) and introduced into simplified models of gas exchange by Withers (Withers, 1978) and Wilson and Kilgore (Wilson and Kilgore, 1978). Wilson and Kilgore developed a mathematical model in which they considered gas diffusion to be the sole mechanism for exchange and showed that in this case soil porosity is the most important variable affecting the rate of respiratory gas transfer in (O 2 ) and out (CO 2 ) of the burrow, more important than the depth of the burrow or the size of the animal.…”

Section: Research Articlementioning

confidence: 99%

“…Wilson and Kilgore developed a mathematical model in which they considered gas diffusion to be the sole mechanism for exchange and showed that in this case soil porosity is the most important variable affecting the rate of respiratory gas transfer in (O 2 ) and out (CO 2 ) of the burrow, more important than the depth of the burrow or the size of the animal. The permeability of the soil to gas diffusion may change because of the presence of water that completely or partially clogs the pores that permeate the soil (Arieli, 1979;Hillel, 1998). Further, a reduction in pore diameter and pore size distribution in the upper soil layer may be caused by the impact of raindrops, which create an abiotic crust (Carmi and Berliner, 2008), and/or by its colonization by bacteria and fungi (reviewed by Belnap et al, 2006), which form a biological crust.…”

Section: Research Articlementioning

confidence: 99%

“…Roper et al, 2001), differ little from atmospheric values. In other instances, the assumption is upheld; namely, high maximum F CO 2 and/or low F O 2 have been reported, for example, in burrows of Middle East blind mole rats Spalax ehrenbergi (Arieli, 1979) and for golden hamsters Mesocricetus auratus (Kuhnen, 1986). Context is important to these results.…”

Section: Introductionmentioning

confidence: 99%

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Ventilation of multi-entranced rodent burrows by boundary layer eddies

Brickner-Braun

Zucker-Milwerger

Braun

et al. 2014

Journal of Experimental Biology

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Rodent burrows are often assumed to be environments wherein the air has a high concentration of CO 2 . Although high burrow [CO 2 ] has been recorded, many studies report burrow [CO 2 ] that differs only slightly from atmospheric concentrations. Here, we advocate that one of the reasons for these differences is the penetration into burrows of air gusts (eddies), which originate in the turbulent boundary layer and prevent build-up of CO 2 . We have characterized the means by which burrows of Sundevall's jird, which are representative of the burrows of many rodent species with more than one entrance, are ventilated. Our results demonstrate that, even at low wind speeds, the random penetration of eddies into a burrow through its openings is sufficient to keep the burrow [CO 2 ] low enough to be physiologically inconsequential, even in its deep and remote parts.

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The atmospheric environment of the fossorial mole rat (Spalax ehrenbergi): Effects of season, soil texture, rain, temperature and activity

Cited by 91 publications

References 22 publications

No oxygen? No problem! Intrinsic brain tolerance to hypoxia in vertebrates

No oxygen? No problem! Intrinsic brain tolerance to hypoxia in vertebrates

The energetics of huddling in two species of mole-rat (Rodentia: Bathyergidae)

Ventilation of multi-entranced rodent burrows by boundary layer eddies

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