Summary
The lungs of two fossorial rodents, the mole ratTachyoryctes splendens and the naked mole ratHeterocephalus glaber were investigated by transmission and scanning electron microscopy and a comparative morphometric analysis of the lungs carried out in an attempt to find out whether there are any possible structural adaptational features which may be associated with fossoriality. The data from these two ecologically disparate fossorial rodents were compared with those of surface dwelling rodents on which equivalent data are available. Morphologically, the lung ofT. splendens is essentially similar to that of terrestrial mammals while that ofH. glaber shows features of underdevelopment. InH. glaber, a cuboidal epithelium extends down the respiratory tree to line what appear to be alveolar spaces, the blood capillaries constitute a double capillary system and the type I pneumocytes have microvilli on their free surface. Morphometrically,H. glaber has notably lower values indicative of rather unspecialized lungs. While the volume density of the parenchyma is 88% inT. splendens, that inH. glaber is only 76%. The blood-gas (tissue) barrier inH. glaber is notably thicker than inT. splendens. When normalized with body weight, the surface area of the blood-gas (tissue) barrier, the pulmonary capillary blood volume, the diffusing capacities of the tissue barrier and of the whole lung are consistently appreciably lower inH. glaber. When compared withMus musculus, Rattus rattus andCavia porcellus, T. splendens has somewhat comparable values with the surface dwelling rodents but the values ofH. glaber are the lowest in the group. It is suggested thatT. splendens has not undergone full adaptation to fossoriality as is supported by its behavioural activities, particularly those of occasionally surfacing to feed and making overland excursions. The low values ofH. glaber may be commensurate with its extreme physiological adaptations for fossoriality, features which culminate in low basal metabolism and may in part explain paedomorphic traits of its respiratory system.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Alexander RD (1991) Some unanswered questions about naked mole-rats. In: Sherman PW, Jarvis JUM, Alexander RD (eds) The biology of the naked mole-rat. Princeton University Press, Princeton, NJ, pp 446–465
Ar A, Arieli R, Shkolnik A (1977) Blood gas properties and function in the fossorial mole rat under normal and hypoxic-hypercapnic atmospheric conditions. Respir Physiol 30:201–218
Arieli R (1979) The atmospheric environment of the fossorial mole rat (Spalax ehrenbergi): effect of season, soil texture, rain, temperature, and activity. Comp Biochem Physiol 63A:569–575
Arieli R, Ar A (1979) Ventilation of a fossorial mammalSpalax ehrenbergi in hypoxic and hypercapnic conditions. J Appl Physiol 47:1011–1017
Arieli R, Ar A, Shkolnik A (1977) Metabolic responses of a fossorial rodent (Spalax ehrenbergi) to simulated burrow conditions. Physiol Zool 50:61–75
Ayala FJ, Valentine JW (1979) Evolving: The theory and the processes of organic evolution. Benjamin Cummings, Menlo Park, CA
Baudinette RV (1972) Energy metabolism and evaporative water loss in the California ground squirrel: effects of burrow temperature and water vapour pressure. J Comp Physiol 81:57–72
Bhattia B, George S, Rao TL (1969) Hypoxia and poilikothermia in rats. J Appl Physiol 27:583–586
Boggs DF, Kilgore DL, Birchard GF (1984) Respiratory physiology of burrowing mammals and birds. Comp Biochem Physiol 77A:1–7
Breeze RG, Wheeldon EB (1975) The cells of the pulmonary airways. Ann Rev Respir Dis 116:705–777
Brett RA (1991) The population structure of naked mole rat colonies. In: Sherman PW, Jarvis JUM, Alexander RD (eds) The Biology of the naked mole rat. Princeton (New Jersey), Princeton University Press, 97–136
Burri PH (1974) The postnatal growth of the rat lung. III. Morphology. Anat Rec 180:77–98
Burri PH, Weibel ER (1971) Morphometric estimation of pulmonary diffusion capacity. II. Effect pO2 on the growing lung to hypoxia and hyperoxia. Respir Physiol 11:247–264
Burri PH, Weibel ER (1977) The ultrastructure and morphometry of the developing lung. In: Hodson WA (ed) Lung biology in health and disease: development of the lung. Mercel Dekker, New York, pp 215–268
Chapman RC, Bennet AF (1975) Physiological correlates of burrowing in rodents. Comp Biochem Physiol 51A:599–603
Chew R, Lindberg G, Hyden P (1965) Circadian rhythm of metabolic rate in pocket mice. J Mammal 46:477–494
Darden TR (1970) Respiratory adaptations of a fossorial mammal, the pocket gopher (Thomomys bottae). PhD dissertation, University of California (Davis)
Eloff G (1951) Adaptation in rodent moles and insectivorous moles and the theory of convergence. Nature (London) 168:1001–1002
Faleschini RJ, Whitten BK (1975) Comparative hypoxic tolerance in Sciuridae. Comp Biochem Physiol 52A:217–221
Forrest JB, Weibel ER (1975) Morphometric estimation of pulmonary diffusion capacity. IV. The normal guinea pig lung. Respir Physiol 24:191–202
Geelhaar A, Weibel ER (1971) Morphometric estimation of pulmonary diffusion capacity. III. The effect of increased oxygen consumption in Japanese waltzing mice. Respir Physiol 11:354–366
Gehr P, Mwangi DK, Amman A, Maloiy GMO, Taylor CR, Weibel ER (1981) Design of the mammalian respiratory system. IV. Scaling morphometric pulmonary diffusing capacity to body mass: wild and domestic mammals. Respir Physiol 44:61–86
Gettinger RD (1975) Metabolism and thermoregulation of a fossorial rodent, the northern pocket gopher (Thomomys talpoides). Physiol Zool 48:311–322
Hall FG (1965) Haemoglobin and oxygen affinities in seven species of Sciuridae. Science 148:1350–1351
Hayden JS (1966) Abnormal concentrations of respiratory gases in rabbit burrows. J Mammal 47:723
Hill OCW, Porter A, Bloom RT, Seago J, Southwick MD (1957) Field and laboratory studies on the naked mole ratHeterocephalus glaber. Proc Zool Soc (London) 128:455–514
Hyden P, Lindberg R (1970) Hypoxia induced torpor in pocket mice (genus Perognathus). Comp Biochem Physiol 33A:167–179
Jarvis JUM (1973) Activity patterns in the mole-ratsTachyoryctes splendens andHeliophobius argenteocinereus. Zool Afr 8:101–119
Jarvis JUM (1978) Energetics of survival inHeterocephalus glaber (Ruppell), the naked mole rat (Rodentia: Bathyergidae). In: Schlitter DA (ed) Bulletin of Carnegie Museum of Natural History (No. 6). Pittsburgh, Trustees of Carnegie Institute, pp 81–87
Jarvis JUM (1984) African mole rats. In: MacDonald D (ed) Encyclopedia of mammals, vol 2. London, Allen Unwin, pp 708–711
Jarvis JUM, Sale JB (1971) Burrowing and burrow patterns of East African mole ratsTachyoryctes, Heliophobius andHeterocephalus. J Zool (London) 163:451–475
Kilgore DL, Birchard GF (1980) Respiratory functions of blood in burrowing and nonburrowing birds. Am Zool 20:766–778
Lovegrove BG, Wissel C (1988) Sociality in mole rats: Metabolic scaling and the role of risk sensitivity. Oecologia (Berlin) 74:600–606
Maclean GS (1981) Factors influencing the composition of respiratory gases in mammal burrows. Comp Biochem Physiol 69A:373–380
Maina JN (1987) The morphology of the lung of the African lungfish (Protopterus aethiopicus): A scanning electron microscopic study. Cell Tissue Res 250:191–196
Maina JN, Maloiy GMO (1988) A scanning and transmission electron microscopic study of the lung of a caecilianBoulengerula taitanus. J Zool (London) 215:739–751
Maina JN, King AS, Settle G (1989) An allometric study of pulmonary parameters in birds, with mammalian comparisons. Phil Trans R Soc London B 326:1–57
Mayer WW (1955) The protective value of the burrow system to the hibernating Arctic ground squirrel (Spermophilus tridecemlineatus). Anat Rec 122:437–438
McNab B (1966) The metabolism of fossorial rodents: a study of convergence. Ecology 47:712–733
McNab B (1979) The influence of body size on the energetics and distribution of fossorial and burrowing mammals. Ecology 60:1010–1021
McNab B (1988) Complications inherent in scaling the basal metabolism in mammals. Quart Rev Biol 63:25–54
Meban C (1980) Thickness of the air-blood barrier in vertebrate lungs. J Anat 131:299–307
Perry SF (1983) Reptilian lungs: Functional anatomy and evolution. Adv Anat Embryol Cell Biol 79:1–81
Scherle WF (1970) A simple method for volumetry in organs in quantitative stereology. Mikroskopie 26:57–60
Schmidt-Nielsen B, Schmidt-Nielsen K (1950) Evaporative water loss in desert rodents in their natural habitat. Ecology 31:75–85
Sherman PW, Jarvis JUM, Alexander RD (1991) The biology of the naked mole-rat. Princeton (New Jersey), Princeton University Press
Studier EH, Proctor JW (1971) Respiratory gases in burrows ofSpermophilus tridecemlineatus. J Mammal 52:631–633
Thigpen LW (1940) Histology of a normally hairless rodent. J Mammal 21:449–456
Tucker CE, James WE, Berry MA, Johnstone CJ, Glover RF (1976) Depressed myocardial function in the goat at high altitude. J Appl Physiol 41:356–361
Weibel ER (1970/71) Morphometric estimation of pulmonary diffusion capacity. I. Model and method. Respir Physiol 11:54–75
Weibel ER (1979) Stereological Methods: Practical methods for biological morphometry. London, Academic Press
Weibel ER (1984) The pathway for oxygen. Harvard University Press, Cambridge, MA
Weibel ER, Claassen H, Gehr P, Sehovic S, Burri P (1980) The respiratory system of the smallest mammal. In: Schmidt-Nielsen K, Bolis L, Taylor CR (eds) Comparative physiology of primitive mammals. Cambridge University Press, Cambridge
Xu L, Mortola JP (1989) Effects of hypoxia on the lung of the chick embryo. Can J Physiol Pharmacol 67:515–519
Yanav S, Buffenstein R, Jarvis JUM, Mitchell D (1989) Thermoregulation and evaporative water loss in the naked mole-rat,Heterocephalus glaber. S Afr J Sci 85:340
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Maina, J.N., Maloiy, G.M.O. & Makanya, A.N. Morphology and morphometry of the lungs of two East African mole rats,Tachyoryctes splendens andHeterocephalus glaber (Mammalia, Rodentia). Zoomorphology 112, 167–179 (1992). https://doi.org/10.1007/BF01633107
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF01633107