Physiological correlates of burrowing in rodents

Abstract

Abstract-1. Blood properties of valley pocket gophers, Thomomys bottae, and laboratory rats, Ratfus norvegicus, were examined to determine blood buffering capabilities.2. Hematocrit, plasma proteins and inorganic phosphate levels were not significantly different between these species.3. Oxygen capacity of the pocket gophers, 23.1 vol%, was greater than that of the rats, 20.8 ~0 1 % . 4. Bicarbonate concentration of pocket gopher blood, 28.1 mM/l., was significantly greater than that of the rats, 19.8 mM/1.5. The non-carbonic buffering strength as determined from CO, titration curves of whole blood of pocket gophers, -2.67 logpCO,/pH unit, was greater than that of the rats, -1.39 logpCO,/pH,unit. 6.The greater buffering capacity of pocket gopher blood may account for the reduced sensltlvlty of ventilation rate in response to elevated burrow CO, concentrations.

The hypoxia tolerance of eight related African mole‐rat species rivals that of naked mole‐rats, despite divergent ventilatory and metabolic strategies in severe hypoxia

“…In social species where numerous animals live within the confined space of the nest, and there is poor gas diffusion through the surrounding soils, the conditions faced (intermittent acute (or chronic) hypoxic and hypercarbic conditions) can be severe. However, reports of the composition of gases, and thus the severity of hypoxia and hypercarbia, in burrows of fossorial species vary greatly, from 20 to 6 kPa O 2 and 1 to 9.5 kPa CO 2 . The timing and location of burrow measurements presumably contribute to this variability, as well as other factors, such as burrow structure, soil type, number of occupants and degree of fossoriality …”

“…However, reports of the composition of gases, and thus the severity of hypoxia and hypercarbia, in burrows of fossorial species vary greatly, from 20 to 6 kPa O 2 and 1 to 9.5 kPa CO 2 . 1,[4][5][6][7][8][9] The timing and location of burrow measurements presumably contribute to this variability, as well as other factors, such as burrow structure, soil type, number of occupants and degree of fossoriality. 1,10 The response to hypoxia in mammals may consist of increases in ventilation (to match O 2 supply to metabolic demand; the hypoxia ventilatory response), decreases in metabolic rate (to match metabolic demand to O 2 supply; the hypoxic metabolic response) or a combination of the two.…”

Haematological and serum biochemistry profile of the juvenile wild African giant rat (Cricetomys gambianus, Waterhouse – 1840) in Nsukka, South-Eastern Nigeria – a preliminary investigation

“…Principally, the African giant rat lives in burrows of low oxygen concentration of 6% and high carbon dioxide of 3.8% and comes out at night in search for food (Ibe et al 2011). The condition of the burrows may have an impact on the structural components of the cardiovascular and respiratory systems, haematology and blood chemistry parameters (Chapman & Bennet 1975). These rats are also found in forests, thickets, pits and bushes, although many thrive in urban and suburban settings (Cooper & Erlwanger 2007).…”

Effects of temperature and light on the locomotory activity of captive pocket gophers

“…Vaughan & Hansen (1961) found that natural light had little effect on the locomotory activity of captive Geomys bursarius, and suggested that the major effect of temperature is likely the effect temperature has on seasonal rates of metabolism (seasonal metabolic changes were noted by Geomys pinetis in Florida by Ross, 1980), and that diel activity may be considered directly dependent on metabolic demands. In addition to temperature, metabolism may also be influenced by the level of various gases in the confined space of burrows, despite, for example, specific physiological adaptation to high levels of CO2 (Darden, 1972;Chapman & Bennett, 1975), which in turn would be influenced by permeability of the soil under both wet and dry conditions (Arieli, 1979). Bandoli (1981) noted that the burrowing activity of Thomomys bottae in Arizona was not directly influenced by precipitation, but rather by the availability of preferred foods and the seeking of mates, while Hickman (1975) noted that Pappogeomys may spend little time outside of the nest when carying for young.…”