The diving capabilities of Nerodia erythrogaster flavigaster and Nerodia fasciata confluens were investigated and the results were compared with similar studies on Nerodia rhombifera rhombifera and Elaphe obsoleta obsoleta (Baeyens et al., 1978). In addition, morphological and hematological parameters contributing to underwater survival were examined. The duration of underwater survival for N. erythrogaster and N. fasciata was approximately one hour with no difference between the species. The lung volumes of the two species were also similar but were significantly less than lung volumes reported for E. obsoleta. There were no significant differences in hemoglobin concentration, red blood cell count or hematocrit between N. rhombifera, N. erythrogaster, N. fasciata, and E. obsoleta. Based on similarities in underwater tolerance, lung morphology and hematology, Nerodia more closely resembles the terrestrial E. obsoleta than those reptiles specifically adapted to an underwater existance

Baeyens, Dennis A.

McAllister, Chris T.

Patterson, M. W.

English

UARK (University of Arkansas )

Journal of the Arkansas Academy of Science Volume 33 Article 8 1979 Hematology as Related to Diving Characteristics of Elaphe obsoleta, Nerodia erythrogaster, Nerodia Fasciata and Nerodia rhombifera Dennis A. Baeyens University of Arkansas at Little Rock M. W. Patterson University of Arkansas at Little Rock Chris T. McAllister University of Arkansas at Little Rock Follow this and additional works at: https://scholarworks.uark.edu/jaas  Part of the Hematology Commons, and the Terrestrial and Aquatic Ecology Commons Recommended Citation Baeyens, Dennis A.; Patterson, M. W.; and McAllister, Chris T. (1979) "Hematology as Related to Diving Characteristics of Elaphe obsoleta, Nerodia erythrogaster, Nerodia Fasciata and Nerodia rhombifera," Journal of the Arkansas Academy of Science: Vol. 33 , Article 8. Available at: https://scholarworks.uark.edu/jaas/vol33/iss1/8 This article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able to read, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author. This Article is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the Arkansas Academy of Science by an authorized editor of ScholarWorks@UARK. For more information, please contact scholar@uark.edu. Arkansas Academy of Science Proceedings, Vol.XXXIII,1979 17Hematology as Related to DivingCharacteristics ofElaphe obsoleta, Nerodia erythrogaster,Nerodia fasciata and Nerodia rhombiferaDENNIS A. BAEYENS, M.W. PATTERSON and C.T. MCALLISTERDepartment of BiologyUniversity of Arkansas at Little RockLittle Rock, Arkansas 72204ABSTRACTThe diving capabilities ofNerodia erythrogaster flavigaster and Nerodia fasciata confluenswere investigated and the results were compared with similar studies on Nerodia rhombiferarhombifera and Elaphe obsoleta obsoleta (Baeyens et al., 1978). Inaddition, morphological andhematological parameters contributing to underwater survival were examined.The duration of underwater survival for N. erythrogaster and N. fasciata was approximatelyone hour with no difference between the species. The lung volumes of the two species werealso similar but were significantly less than lung volumes reported for E. obsoleta. There wereno significant differences in hemoglobin concentration, red blood cell count or hematocritbetween N. rhombifera, N. erythrogaster, N. fasciata, and E.obsoleta. Based on similarities inunderwater tolerance, lung morphology and hematology, Nerodia more closely resembles theterrestrial E. obsoleta than those reptiles specifically adapted to an underwater existance.INTRODUCTIONCertain representatives from all the vertebrate classes display pro-nounced respiratory and cardiovascular changes inresponse to sub-mergence. These animals, collectively referred to as the divingani-mals, are physiologically and morphologically suited for underwatersurvival. Most of the experimentation to date has focused on the div-ing mammals and birds, and relatively little is known of the physiolo-gy ofdivingreptiles.This study represents a continuation of work reported earlier(Baeyens et al., 1978) and has two specific purposes. First, to com-pare the divingabilities of two species of water snakes (Nerodia ery-throgaster flavigaster, and Nerodia fasciata confluens) withthe divingabilityof the terrestrial black rat snake. Second, to explore some ofthe hemotological and morphological attributes which might contri-bute tounderwater survival inN. erythrogaster, N. faciata, N. rhom-Kfera and E. obsoleta.close observation after surfacing to insure that they were not seri-ouslv impaired as a result of thedive.Lung volumes were determined for N. erythrogaster and N. fas-ciata by injecting air into the lunguntil the point of maximal lung ex-pansion was reached (Baeyens et al., 1978). The lung capacities areexpressed interms of mlper kg bodyweight.Inall four species blood samples were collected from the hepaticportal vein witha 23 gauge needle fitted to a 5 cc syringe containingEDTA as an anticoagulant. Approximately 4 mlof blood were drawnfrom each animal. Hemoglobin concentration was measured as cyan-methemoglobin using Drabkin's diluent (Davidsohn and Wells,1963). For hematocrit determinations, nonheparinized capillarytubes were filled with blood and one end was sealed with clay. Thetubes were immediately centrifuged at approximately 10,000 RPMfor ten minutes. Red blood cells were counted with a standardNeubauer counting chamber with Hayem's solution as the diluent(Davidsohn and Wells, 1963). Fivered blood cell counts were madeforeach snake and the average was recorded.MATERIALS AND METHODSSpecimens ofN. erythrogaster, N.fasciata andN. rhombifera werelected at night from various minnow farms in Lonoke County,cansas. /•'. obsoleta were collected during the day from woodedas inPulaski County, Arkansas. Weights of all the experimentalraals ranged between 450 and 800 g. Most snakes were utilizedhin one week of capture. Snakes kept in captivity over two weeksre fed leopard frogs and minnows (Nerodia) or small miceElaphe). Most experiments were carried out between March andptember, a period during which snakes are most active in Arkan-.For statistical analysis a Student-Newman-Keuls test was used toke multiple comparisons among means, and values considerednificantly different have ap value of0.05 or less (Sokal and Rohlf ,%9).iFheduration of underwater survival for N. erythrogasier and N.data was determined by subjecting the snakes to involuntary divespreviously described (Baeyens et al., 1978). The dive began the in-nt the animal voluntarily submerged its external nares at which»e the cage containing the animal was totally submerged. The»kes were kept under close observation throughout the dive. Ter-nation of the dive occurred at the first sign of stress. The outwardlications of stress varied from snake to snake but were usually as-Mated witha release of air from the lung and a sudden increase inlivityin an attempt to reach the surface. Snakes remained underRESULTSDiveTimes-Snakes were closely watched throughout the dive andat the first sign of stress the dive was terminated. When a snake wasseverely stressed as a result of a dive, it would be comatose andwould take several hours to recover. Dive times were recorded onlyfor those snakes which showed no signs of hypoxic stress upon sur-facing.Members of each species tolerated dive periods exceeding onehour (Table 1). There were no significant differences in the submer-gence times of the two species.Lung Morphology - In both N. erythrogaster and N. fasciata theleft lung has been lost, and the right lung is a simple tubular-shapedstructure. The general lung structure of both species was similar tothat described for N. rhombifera and E. obsoleta (Baeyens et al..1978). The vascular portion of the lung comprised 24% of the totallung length inN. erythrogaster and N. fasciata. and there were nosignificant differences in total lungvolume between the species. Thelung volumes of N. erythrogaster and N. fasciata were similar tovalues reported for N. rhombifera but were significantly less thanvalues reported for£. obsoleta (Table 1).Hemoiology - The results of the hematology studies are given inTable 2. Statistical analysis revealed no significant differences withinorbetween species inany of the hematological values measured.17Journal of the Arkansas Academy of Science, Vol. 33 [1979], Art. 8Published by Arkansas Academy of Science, 197918 Arkansas Academy of Science Proceedings, Vol.XXXIII,1979Table 1. Dive times and lungvolumes forNerodia and Elaphe.Dive Time (min) Lung Volume (ml/kg body wt)Mean + S E (N) Mean + S E (N)( )SpeciesH. erythrogaster 78.4 + 17.6 (10) 64.0 + 12.2 (10)N. fasciata 59.3 + 20.2 ( 5) 61.4 + 9.2 ( 5)N. rhombifera 1 68.3+ 9.2 (10) 51.7+ 11.1 (12)E. obsoleta 1 70.5 + 8.3 ( 9) 80.2 + 12.7 ( 6)*'Significant difference fromNerodia at the 5% level.¦From Baeyens et al. 1978.Table 2. Hematocrits (PCV), hemoglobin concentrations (Hb)andred blood cell counts (RBC) forNerodia andElaphe.Number , ,Species of Snakes PCV* Hb g% RBC/mm J(X10 t> )H. erythrogaster 10 28.8+4.5 10.7+1.2 0.71+0.07N. fasciata 5 29.0 + 6.9 9.7 + 1.6 0.57 + 0.03N. rhombifera 10 32.3 + 3.5 10.9 + 2.1 0.75 + 0.09E. obsoleta 7 31.6+3.5 11.5+2.2 0.69+0.04DISCUSSIONTwo areas whichmay be utilized for oxygen storage during a diveare the lungs and the blood. The lung and air sac volumes of divingmammals and birds are not significantly larger than those of their ter-restrial counterparts (Scholander and Irving, 1941). Andersen (1961)found that the lung volume of the alligator, an excellent reptiliandiver,ranges from 76 to 102 ml/kg. This is somewhat higher than thevalues reported for diving mammals, but lower than those reportedfordiving birds (Eliassen, 1960). The lung of the completely aquaticmarine snake Pelamis platuris fills the entire coelomic cavity extend-ing from the neck to the vent (Heatwole and Seymour, 1975). The im-mensity of the lungin this species is also reflected byits large volume(580 ml/kg body weight). Incontrast, the lung volumes were muchsmaller inthe two species we studied (Table 1). Since the lung volumeof Nerodia is somewhat smaller than the terrestrial Elaphe, it doesnot appear that the lung ofNerodia is particularly adapted as an im-portant oxygen storage organ for underwater activity.The role of elevated hemoglobin concentration foroxygen storagehas been shown to be of importance in diving mammals and birds(Andersen, 1966). The importance of hemoglobin concentration indiving reptiles has been difficult to ascertain because of the widevariations inreported values (Seymour and Webster, 1975; Dessauer,1970). The present study indicates a similarity in hemoglobin con-centration between Nerodia and Elaphe. These values fall within therange of hemoglobin concentrations found in sea snakes (Seymourand Webster, 1975). Red blood cell counts and hematocrits were alsosimilar in the four species studied. These similarities agree withHutton's (1958) findings of no consistent differences in either redblood cell counts or hematocrits between aquatic and terrestrialsnakes.Based on the parameters examined, Nerodia appears to be nobet-ter adapted for an aquatic existence than is the terrestrial Elaphe.(Baeyens et al., 1978). The survival time of Nerodia when forciblysubmerged isno longer than that of Elaphe, and is much shorter thanfor some turtles and sea snakes which can remain underwater forseveral hours (Pickwell, 1972; Graham, 1974). The similarities inhemoglobin concentration inNerodia and Elaphe suggest that theblood does not have a unique oxygen storage capacity to facilitateunderwater survivalinNerodia. Inthe same regard, the lung volumeof Nerodia is smaller than that of Elaphe, and a great deal smallerthan the lung volume of sea snakes. Based on the similarities in lungstructure, hematology and underwater tolerance between Nerodiaand Elaphe, it would seem that some of the physiological potentialfor an aquatic existence is already present inthe black rat snake andpresumably inother terrestrial species as well.ACKNOWLEDGEMENTSWe wish to thank Dr. Thomas Lynch and Dr.PhyllisGarnett for critically reviewing the manuscript andoffering helpful suggestions during itspreparation. Weare also indebted to Charles Calhoun and Joe Bailey fortheir helpincollecting the animals used in this study.LITERATURE CITEDANDERSEN, H. T. 1961. Physiological adjustments to prolongeddiving in the American alligator Alligatormississipiensis. Acta.physiol. scand. 53:23-45.ANDERSEN, H. T. 1966. Physiological adaptations in diving verte-brates. Physiol. Rev. 46:212-243.BAEYENS, D. A.. C. T.MCALLISTER and L.F. MORGANS.1978. Some physiological and morphological adaptations forunderwater survivalinNatrix rhombifera and Elaphe obsoleta.Ark.Acad. Sci.Proc. 32:18-21.DAVIDSOHN,I.and B.B. WELLS. 1963. Clinical diagnosis by labo-ratory methods. W. B. SaundersCo., Philadelphia. 1020 pp.DESSAUER, H.C. 1970. Biology of the reptilia. Vol.3. C. Gans andT.S.Parsons eds. Academic Press, New York. 385 pp.IELIASSEN,E. 1960. Cardiovascular responses to submersion asphy-xia inavian divers. Arbok Univ.Bergen, Mat.- Nat., Ser. no. 2.GRAHAM,J. B. 1974. Aquatic respiration in the sea snake Pelamisplaturis. Respir. Physiol. 21:1-7.HEATWOLE, H., and R. SEYMOUR. 1975. The biology of seasnakes. University Park Press, Baltimore. 530 pp.HUTTON,K.E. 1958. The blood chemistry of terrestrial and aquaticsnakes. J. Cell.Comp. Physiol. 52:319-328.PICKWELL,G. V.1972. The venomous sea snakes. Fauna 4:16-32.SCHOLANDER. P. G. and L.IRVING.1941.Respiratory and circu-latory adaptations of diving animals. J. Cell. Comp. Physiol.17:169-191.SEYMOUR,R. S. and M.E. D.WEBSTER. 1975. Gas transport andblood acid-base balance in diving sea snakes. J. Exp. Zool.169-181.SOKAL, R. R. and F. J. ROHLF. Biometry. W. H. Freeman, SanFrancisco. 776 pp.18Journal of the Arkansas Academy of Science, Vol. 33 [1979], Art. 8https://scholarworks.uark.edu/jaas/vol33/iss1/8

Hematology as Related to Diving Characteristics of Elaphe obsoleta, Nerodia erythrogaster, Nerodia Fasciata and Nerodia rhombifera

ScholarWorks@UARK

Journal of the Arkansas Academy of ScienceVolume 33 Article 81979Hematology as Related to Diving Characteristics ofElaphe obsoleta, Nerodia erythrogaster, NerodiaFasciata and Nerodia rhombiferaDennis A. BaeyensUniversity of Arkansas at Little RockM. W. PattersonUniversity of Arkansas at Little RockChris T. McAllisterUniversity of Arkansas at Little RockFollow this and additional works at: http://scholarworks.uark.edu/jaasPart of the Hematology Commons, and the Terrestrial and Aquatic Ecology CommonsThis article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able toread, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking priorpermission from the publisher or the author.This Article is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the Arkansas Academyof Science by an authorized editor of ScholarWorks@UARK. For more information, please contact scholar@uark.edu, ccmiddle@uark.edu.Recommended CitationBaeyens, Dennis A.; Patterson, M. W.; and McAllister, Chris T. (1979) "Hematology as Related to Diving Characteristics of Elapheobsoleta, Nerodia erythrogaster, Nerodia Fasciata and Nerodia rhombifera," Journal of the Arkansas Academy of Science: Vol. 33 , Article8.Available at: http://scholarworks.uark.edu/jaas/vol33/iss1/8Arkansas Academy of Science Proceedings, Vol.XXXIII,1979 17Hematology as Related to DivingCharacteristics ofElaphe obsoleta, Nerodia erythrogaster,Nerodia fasciata and Nerodia rhombiferaDENNIS A. BAEYENS, M.W. PATTERSON and C.T. MCALLISTERDepartment of BiologyUniversity of Arkansas at Little RockLittle Rock, Arkansas 72204ABSTRACTThe diving capabilities ofNerodia erythrogaster flavigaster and Nerodia fasciata confluenswere investigated and the results were compared with similar studies on Nerodia rhombiferarhombifera and Elaphe obsoleta obsoleta (Baeyens et al., 1978). Inaddition, morphological andhematological parameters contributing to underwater survival were examined.The duration of underwater survival for N. erythrogaster and N. fasciata was approximatelyone hour with no difference between the species. The lung volumes of the two species werealso similar but were significantly less than lung volumes reported for E. obsoleta. There wereno significant differences in hemoglobin concentration, red blood cell count or hematocritbetween N. rhombifera, N. erythrogaster, N. fasciata, and E.obsoleta. Based on similarities inunderwater tolerance, lung morphology and hematology, Nerodia more closely resembles theterrestrial E. obsoleta than those reptiles specifically adapted to an underwater existance.INTRODUCTIONCertain representatives from all the vertebrate classes display pro-nounced respiratory and cardiovascular changes inresponse to sub-mergence. These animals, collectively referred to as the divingani-mals, are physiologically and morphologically suited for underwatersurvival. Most of the experimentation to date has focused on the div-ing mammals and birds, and relatively little is known of the physiolo-gy ofdivingreptiles.This study represents a continuation of work reported earlier(Baeyens et al., 1978) and has two specific purposes. First, to com-pare the divingabilities of two species of water snakes (Nerodia ery-throgaster flavigaster, and Nerodia fasciata confluens) withthe divingabilityof the terrestrial black rat snake. Second, to explore some ofthe hemotological and morphological attributes which might contri-bute tounderwater survival inN. erythrogaster, N. faciata, N. rhom-Kfera and E. obsoleta.close observation after surfacing to insure that they were not seri-ouslv impaired as a result of thedive.Lung volumes were determined for N. erythrogaster and N. fas-ciata by injecting air into the lunguntil the point of maximal lung ex-pansion was reached (Baeyens et al., 1978). The lung capacities areexpressed interms of mlper kg bodyweight.Inall four species blood samples were collected from the hepaticportal vein witha 23 gauge needle fitted to a 5 cc syringe containingEDTA as an anticoagulant. Approximately 4 mlof blood were drawnfrom each animal. Hemoglobin concentration was measured as cyan-methemoglobin using Drabkin's diluent (Davidsohn and Wells,1963). For hematocrit determinations, nonheparinized capillarytubes were filled with blood and one end was sealed with clay. Thetubes were immediately centrifuged at approximately 10,000 RPMfor ten minutes. Red blood cells were counted with a standardNeubauer counting chamber with Hayem's solution as the diluent(Davidsohn and Wells, 1963). Fivered blood cell counts were madeforeach snake and the average was recorded.MATERIALS AND METHODSSpecimens ofN. erythrogaster, N.fasciata andN. rhombifera werelected at night from various minnow farms in Lonoke County,cansas. /•'. obsoleta were collected during the day from woodedas inPulaski County, Arkansas. Weights of all the experimentalraals ranged between 450 and 800 g. Most snakes were utilizedhin one week of capture. Snakes kept in captivity over two weeksre fed leopard frogs and minnows (Nerodia) or small miceElaphe). Most experiments were carried out between March andptember, a period during which snakes are most active in Arkan-.For statistical analysis a Student-Newman-Keuls test was used toke multiple comparisons among means, and values considerednificantly different have ap value of0.05 or less (Sokal and Rohlf ,%9).iFhe duration of underwater survival for N. erythrogasier and N.data was determined by subjecting the snakes to involuntary divespreviously described (Baeyens et al., 1978). The dive began the in-nt the animal voluntarily submerged its external nares at which»e the cage containing the animal was totally submerged. The»kes were kept under close observation throughout the dive. Ter-nation of the dive occurred at the first sign of stress. The outwardlications of stress varied from snake to snake but were usually as-Mated witha release of air from the lung and a sudden increase inlivityin an attempt to reach the surface. Snakes remained underRESULTSDiveTimes -Snakes were closely watched throughout the dive andat the first sign of stress the dive was terminated. When a snake wasseverely stressed as a result of a dive, it would be comatose andwould take several hours to recover. Dive times were recorded onlyfor those snakes which showed no signs of hypoxic stress upon sur-facing.Members of each species tolerated dive periods exceeding onehour (Table 1). There were no significant differences in the submer-gence times of the two species.Lung Morphology - In both N. erythrogaster and N. fasciata theleft lung has been lost, and the right lung is a simple tubular-shapedstructure. The general lung structure of both species was similar tothat described for N. rhombifera and E. obsoleta (Baeyens et al..1978). The vascular portion of the lung comprised 24% of the totallung length inN. erythrogaster and N. fasciata. and there were nosignificant differences in total lungvolume between the species. Thelung volumes of N. erythrogaster and N. fasciata were similar tovalues reported for N. rhombifera but were significantly less thanvalues reported for£. obsoleta (Table 1).Hemoiology - The results of the hematology studies are given inTable 2. Statistical analysis revealed no significant differences withinorbetween species inany of the hematological values measured.17Journal of the Arkansas Academy of Science, Vol. 33 [1979], Art. 8Published by Arkansas Academy of Science, 197918 Arkansas Academy of Science Proceedings, Vol.XXXIII,1979Table 1. Dive times and lungvolumes forNerodia and Elaphe.Dive Time (min) Lung Volume (ml/kg body wt)Mean + S E (N) Mean + S E (N)( )SpeciesH. erythrogaster 78.4 + 17.6 (10) 64.0 + 12.2 (10)N. fasciata 59.3 + 20.2 ( 5) 61.4 + 9.2 ( 5)N. rhombifera 1 68.3+ 9.2 (10) 51.7+ 11.1 (12)E. obsoleta 1 70.5 + 8.3 ( 9) 80.2 + 12.7 ( 6)*'Significant difference fromNerodia at the 5% level.¦From Baeyens et al. 1978.Table 2. Hematocrits (PCV), hemoglobin concentrations (Hb)andred blood cell counts (RBC) forNerodia andElaphe.Number , ,Species of Snakes PCV* Hb g% RBC/mm J(X10 t> )H. erythrogaster 10 28.8+4.5 10.7+1.2 0.71+0.07N. fasciata 5 29.0 + 6.9 9.7 + 1.6 0.57 + 0.03N. rhombifera 10 32.3 + 3.5 10.9 + 2.1 0.75 + 0.09E. obsoleta 7 31.6+3.5 11.5+2.2 0.69+0.04DISCUSSIONTwo areas whichmay be utilized for oxygen storage during a diveare the lungs and the blood. The lung and air sac volumes of divingmammals and birds are not significantly larger than those of their ter-restrial counterparts (Scholander and Irving, 1941). Andersen (1961)found that the lung volume of the alligator, an excellent reptiliandiver,ranges from 76 to 102 ml/kg. This is somewhat higher than thevalues reported for diving mammals, but lower than those reportedfordiving birds (Eliassen, 1960). The lung of the completely aquaticmarine snake Pelamis platuris fills the entire coelomic cavity extend-ing from the neck to the vent (Heatwole and Seymour, 1975). The im-mensity of the lungin this species is also reflected byits large volume(580 ml/kg body weight). Incontrast, the lung volumes were muchsmaller inthe two species we studied (Table 1). Since the lung volumeof Nerodia is somewhat smaller than the terrestrial Elaphe, it doesnot appear that the lung ofNerodia is particularly adapted as an im-portant oxygen storage organ for underwater activity.The role of elevated hemoglobin concentration foroxygen storagehas been shown to be of importance in diving mammals and birds(Andersen, 1966). The importance of hemoglobin concentration indiving reptiles has been difficult to ascertain because of the widevariations inreported values (Seymour and Webster, 1975; Dessauer,1970). The present study indicates a similarity in hemoglobin con-centration between Nerodia and Elaphe. These values fall within therange of hemoglobin concentrations found in sea snakes (Seymourand Webster, 1975). Red blood cell counts and hematocrits were alsosimilar in the four species studied. These similarities agree withHutton's (1958) findings of no consistent differences in either redblood cell counts or hematocrits between aquatic and terrestrialsnakes.Based on the parameters examined, Nerodia appears to be nobet-ter adapted for an aquatic existence than is the terrestrial Elaphe.(Baeyens et al., 1978). The survival time of Nerodia when forciblysubmerged isno longer than that of Elaphe, and is much shorter thanfor some turtles and sea snakes which can remain underwater forseveral hours (Pickwell, 1972; Graham, 1974). The similarities inhemoglobin concentration inNerodia and Elaphe suggest that theblood does not have a unique oxygen storage capacity to facilitateunderwater survivalinNerodia. Inthe same regard, the lung volumeof Nerodia is smaller than that of Elaphe, and a great deal smallerthan the lung volume of sea snakes. Based on the similarities in lungstructure, hematology and underwater tolerance between Nerodiaand Elaphe, it would seem that some of the physiological potentialfor an aquatic existence is already present inthe black rat snake andpresumably inother terrestrial species as well.ACKNOWLEDGEMENTSWe wish to thank Dr. Thomas Lynch and Dr.PhyllisGarnett for critically reviewing the manuscript andoffering helpful suggestions during itspreparation. Weare also indebted to Charles Calhoun and Joe Bailey fortheir helpincollecting the animals used in this study.LITERATURE CITEDANDERSEN, H. T. 1961. Physiological adjustments to prolongeddiving in the American alligator Alligatormississipiensis. Acta.physiol. scand. 53:23-45.ANDERSEN, H. T. 1966. Physiological adaptations in diving verte-brates. Physiol. Rev. 46:212-243.BAEYENS, D. A.. C. T.MCALLISTER and L.F. MORGANS.1978. Some physiological and morphological adaptations forunderwater survivalinNatrix rhombifera and Elaphe obsoleta.Ark.Acad. Sci.Proc. 32:18-21.DAVIDSOHN,I.and B.B. WELLS. 1963. Clinical diagnosis by labo-ratory methods. W. B. SaundersCo., Philadelphia. 1020 pp.DESSAUER, H.C. 1970. Biology of the reptilia. Vol.3. C. Gans andT.S.Parsons eds. Academic Press, New York. 385 pp.IELIASSEN,E. 1960. Cardiovascular responses to submersion asphy-xia inavian divers. Arbok Univ.Bergen, Mat.- Nat., Ser. no. 2.GRAHAM,J. B. 1974. Aquatic respiration in the sea snake Pelamisplaturis. Respir. Physiol. 21:1-7.HEATWOLE, H., and R. SEYMOUR. 1975. The biology of seasnakes. University Park Press, Baltimore. 530 pp.HUTTON,K.E. 1958. The blood chemistry of terrestrial and aquaticsnakes. J. Cell.Comp. Physiol. 52:319-328.PICKWELL,G. V.1972. The venomous sea snakes. Fauna 4:16-32.SCHOLANDER. P. G. and L.IRVING.1941.Respiratory and circu-latory adaptations of diving animals. J. Cell. Comp. Physiol.17:169-191.SEYMOUR,R. S. and M.E. D.WEBSTER. 1975. Gas transport andblood acid-base balance in diving sea snakes. J. Exp. Zool.169-181.SOKAL, R. R. and F. J. ROHLF. Biometry. W. H. Freeman, SanFrancisco. 776 pp.18Journal of the Arkansas Academy of Science, Vol. 33 [1979], Art. 8http://scholarworks.uark.edu/jaas/vol33/iss1/8

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Hematology as Related to Diving Characteristics of Elaphe obsoleta, Nerodia erythrogaster, Nerodia Fasciata and Nerodia rhombifera

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