Abstract
Filesnakes (Acrochordus arafurae) are large (to 2 m), heavy-bodied snakes of tropical Australia. Sexual dimorphism is evident in adult body sizes, weight/length ratios, and body proportions (relative head and tail lengths). Dimorphism is present even in neonates. Two hypotheses for the evolution of such dimorphism are (1) sexual selection or (2) adaptation of the sexes to different ecological niches. The hypothesis of sexual selection is consistent with general trends of sexually dimorphic body sizes in snakes, and accurately predicts, for A. arafurae, that the larger sex (female) is the one in which reproductive success increases most strongly with increasing body size. However, the sexual dimorphism in relative head sizes is not explicable by sexual selection.
The hypothesis of adaptation to sex-specific niches predicts differences in habitats and/or prey. I observed major differences between male and female A. arafurae in prey types, prey sizes and habitat utilization (shallow versus deep water). Hence, the sexual dimorphism in relative head sizes is attributed to ecological causes rather than sexual selection. Nonetheless, competition between the sexes need not be invoked as the selective advantage of this character divergence. It is more parsimonious to interpret these differences as independent adaptations of each sex to increase foraging success, given pre-existing sexually-selected differences in size, habitat or behavior. Data for three other aquatic snake species, from phylogenetically distant taxa, suggest that sexual dimorphism in food habits, foraging sites and feeding morphology, is widespread in snakes.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Aleksiuk M, Gregory PT (1974) Regulation of seasonal mating behavior in Thamnophis sirtalis parietalis. Copeia 1974:681–688
Alexander RD, Hoogland JL, Howard RD, Noonan M, Sherman PW (1979) Sexual dimorphism and breeding systems in pinnipeds, ungulates, primates and humans. In: Chagnon NA, Irons W (eds) Evolutionary biology and human social behavior: An anthropological perpective. Duxbury Press, Mass, USA, pp 402–405
Andren C, Nilson G (1981) Reproductive success and risk of predation in normal and melanistic colour morphs of the adder, Vipera berus. Biol J Linn Soc 15:235–246
Andrews RM, Asato T (1977) Energy utilization of a tropical lizard. Comp Biochem Physiol 58A:57–62
Baird RC (1965) Ecological implications of the behaviour of the sexually dimorphic goby Microgobius gulosus (Girard). Publ Inst Mar Sci Univ Texas 10:1–8
Bell HL (1982) Sexual differences in the foraging behaviour of the frill-necked flycatcher Arses telescopthalmus in New Guinea. Aust J Ecol 7:137–147
Berry JF, Shine R (1980) Sexual size dimorphism and sexual selection in turtles (Order Testudines). Oecologia (Berlin) 44:185–191
Bishop KA, Harland WG (1966) Further ecological studies on the freshwater fishes of the Alligator Rivers Region. OSS Research Reports (in press)
Blanchard FN, Blanchard FC (1941) Mating of the garter snake Thamnophis sirtalis sirtalis (Linnaeus). Pap Michigan Acad Sci Arts Lett 27:215–234
Bowen SH (1984) Differential habitat utilisation by sexes of Sarotherodon mossambicus in Lake Valencia, Venezuela: significance for fitness. J Fish Biol 24:115–121
Brown JL (1975) The evolution of behavior. Norton: New York
Carothers JH (1984) Sexual selection and sexual dimorphism in some herbivorous lizards. Am Nat 124:244–254
Catling PM, Freedman B (1980) Food and feeding behavior of sympatric snakes at Amherstburg, Ontario. Can Field-Nat 94:28–33
Clutton-Brock TH, Harvey PH, Rudder B (1977) Sexual dimorphism, socionomic sex ratio and body weight in primates. Nature 269:797–799
Clutton-Brock TH, Guiness FE, Albon SD (1982) Red deer: behavior and ecology of two sexes. University of Chicago Press, Chicago
Crook JH (1972) Sexual selection, dimorphism, and social organisation in the primates. In: Campbell BG (ed) Sexual selection and the descent of Man. Aldine: Chicago, pp 231–281
Crook JH (1973) Darwinism and the sexual politics of primates. Accad Naz Lincei 182:199–217
Darwin C (1974) The descent of man and selection in relation to sex. Murray: London
Davies NB, Halliday TR (1977) Optimal mate selection in the toad Bufo bufo. Nature 269:56–58
Dugan B (1982) The mating behavior of the green iguana, Iguana iguana In: Burghardt GM, Rand AS (eds) Iguanas of the world. Noyes Publ, New Jersey, USA, pp 320–341
Feduccia A, Slaughter BH (1974) Sexual dimorphism in skates (Rajidae) and its possible role in differential niche utilization. Evolution 28:164–168
Finneran LC (1949) A sexual aggregation of the garter snake Thamnophis butleri (Cope). Copeia 1949:141–144
Fitch HS (1956) An ecological study of the collared lizard (Crotaphytus collaris). Univ Kansas Publ Mus Nat Hist 8:213–274
Fitch HS (1976) Sexual size differences in the mainland anoles. Occas Papers Mus Nat Hist Univ Kansas 50:1–21
Fitch HS (1978) Sexual size differences in the genus Sceloporus. univ Kansas Sci Bull 51:441–461
Fitch HS (1981) Sexual size differences in reptiles. Misc Publ Mus Nat Hist Univ Kansas 70:1–72
Gautier-Hion A (1975) Dimorphisme sexuel et organisation sociale chez les cercopithecines forestiers africains. Mammalia 39:365–374
Ghiselin MT (1974) The economy of nature and the evolution of sex. University of California Press, Berkeley
Gill E (1871) The eared seals. Amer Natur 4:675–684
Greene HW (1984) Feeding behavior and diet of the eastern coral snake Micrurus fulvius. In: Contributions to vertebrate ecology and systematics: a tribute to Henry S Fitch. Special Publ Univ Kansas Mus Nat Hist, pp 147–162
Harris VA (1964) The life of the rainbow lizard. Hutchinson, London
Hart BT, McGregor RJ (1980) Limnological survey of eight billabongs in the Magela Creek catchment, Northern Territory. Aust J Mar Freshwater Res 31:611–626
Harvey PH, Kavanagh MJ, Clutton-Brock TH (1978) Sexual dimorphism in primate teeth. J Zool 186:475–486
Harvey RD (1979) Estimating reproductive success in natural populations. Am Nat 114:217–227
Keenlyne KD (1972) Sexual differences in feeding habits of Crotalus horridus horridus. J Herpetol 7:234–237
Keenlyne KD, Beer JR (1974) Food habits of Sistrurus catenatus catenatus. J Herpetol 7:382–384
Kelleway LG (1982) Competition for mates and food items in Vipera berus. Brit J Herpetol 5:225–230
Klauber LM (1943) Tail-length differences in snakes with notes on sexual dimorphism and the coefficient of divergence. Bull Zool Soc San Diego 18:1–60
Lamb T (1984) The influence of sex and breeding condition on microhabitat selection and diet in the pig frog Rana grylio. Am Midl Nat 111:311–318
Legler JM (1960) A simple and inexpensive device for trapping aquatic turtles. Utah Acad Sci Arts Lett 37:63–66
Leutenegger W, Kelly JT (1977) Relationship of sexual dimorphism in canine size and body size to social behavioral and ecological correlates in anthropoid primates. Primates 18:117–136
Mason LG (1977) Prey preferences and ecological sexual dimorphism in Phymata americana Melin. Am Midl Nat 97:293–299
McDowell SB (1975) A catalogue of the snakes of New Guinea and the Solomons, with special reference to those in the Bernice P Bishop Museum. Part II. Anilioidea and Pythoninae. J Herpeteol 9:1–80
McDowell SB (1979) A catalogue of the snakes of New Guinea and the Solomons, with special reference to those in the Bernice P Bishop Museum. Part III Boinae and Acrochordoidea (Reptilia, Serpentes). J Herpetol 13:1–92
McEachran JD (1977) Reply to “sexual dimorphism in skates (Rajidae)”. Evolution 31:218–220
Mushinsky HR, Hebrard JJ, Vodopich DS (1982) Ontogeny of water snake foraging ecology. Ecology 63:1624–1629
Pernetta JC (1977) Observations on the habits and morphology of the sea snake Laticauda colubrina (Schneider) in Fiji. Canad J Zool 55:1612–1619
Pough FH, Groves JD (1983) Specializations of the body form and food habits of snakes. Amer Zool 23:443–454
Reinert HK (1984) Habitat variation within sympatric snake populations. Ecology 65:1673–1682
Reynolds RP, Scott NJ Jr (1982) Use of a mammalian resource by a Chihuahuan desert snake community. In: Scott NJ Jr (ed) Herpetological communities. US Dept of Interior, Fish and Wildlife Service, Wildlife Research Report 13, pp 99–118
Rieppel O (1980) The perilymphatic system of the skull of Typhlops and Acrochordus, with comments on the origin of snakes. J Herpetol 14:105–108
Ruby DE (1981) Phenotypic correlates of male reproductive success in the lizard Sceloporus jarrovi. In: Alexander RD, Tinkle DW (eds) Natural selection and social behavior. Chiron Press, New York, pp 430–438
Schmidt RJ, Holbrook SJ (1984) Gape-limitation, foraging tactics and prey size selectivity of two microcarnivorous species of fish. Oecologia (Berlin) 63:6–12
Schoener TW (1967) The ecological significance of sexual dimorphism in size in the lizard Anolis conspersus. Science 155:474–476
Schoener TW (1969) Models of optimum size for solitary predators. Amer Natur 103:227–313
Schoener TW (1977) Competition and the niche. In: Gans C, Tinkle DW (eds) Biology of the reptilia, vol 7. Academic Press, London, pp 35–136
Schoener TW, Slade JB, Stinson CH (1982) Diet and sexual dimorphism in the very catholic lizard genus, Leiocephalus of the Bahamas. Oecologia (Berlin) 53:160–169
Selander RK (1966) Sexual dimorphism and differential niche utilization in birds. Condor 68:113–151
Selander RK (1972) Sexual selection and dimorphism in birds. In: Campbell BG (ed) Sexual selection and the descent of man. Aldine: Chicago, pp 180–230
Semlitsch RD, Gibbons JW (1982) Body size dimorphism and sexual selection in two species of water snakes. Copeia 1982:974–976
Seymour RS, Dobson GP, Baldwin P (1981) Respiratory and cardiovascular physiology of the aquatic snake, Acrochordus arafurae. J Comp Physiol 144:215–227
Shine R (1977) Habitats, diet and sympatry in snakes: a study from Australia. Can J Zool 55:1118–1128
Shine R (1978) Sexual size dimorphism and male combat in snakes. Oecologia (Berlin) 33:269–277
Shine R (1979) Sexual selection and sexual dimorphism in the Amphibia. Copeia 1979:297–306
Shine R (1980) “Costs” of reproduction in reptiles. Oecologia (Berlin) 46:92–100
Shine R (1986) Ecology of a low energy specialist: food habits and reproductive biology of the Arafura filesnake (Acrochordidae). Copeia 1986:424–437
Shine R, Lambeck R (1985) A radiotelemetric study of movements, thermoregulation and habitat utilization of Arfura filesnakes (Serpentes, Acrochordidae). Herpetologica 41:351–361
Sieb RL (1981) Size and shape in a neotropical burrowing colubrid snake, Geophis nasalis, and its prey. Amer Zool 21:933
Slatkin M (1984) Ecological causes of sexual dimorphism. Evolution 38:622–630
Smith GC (1976) Ecological energetics of three species of ectothermic vertebrates. Ecology 57:252–264
Spassov NB (1979) Sexual selection and evolution of intraspecific display means in baboons (Primates, Cercopithecidae). CR Acad Bulgare Sci 32:225–228
Stamps JA (1977) The relationship between resource competition, risk and aggression in a tropical territorial lizard. Ecology 58:349–358
Stamps JA (1983) Sexual selection, sexual dimorphism, and territoriality. In: Huey RB, Pianka ER, Schoener TW (eds) Lizard ecology. Harvard University Press, Mass, pp 169–204
Trivers RL (1976) Sexual selection and resource-accruing abilities in Anolis garmani. Evolution 30:253–269
Vitt LJ (1983) Reproduction and sexual dimorphism in the tropical teiid lizard Cnemidophorus ocellifer. Copeia 1983:359–366
Voris HK, Voris HH (1983) Feeding strategies in marine snakes: an analysis of evolutionary, morphological, behavioral, and ecological relationships. Amer Zool 23:411–426
Werner DI (1982) Social organization and ecology of land iguanas, Conolophus subcristatus on Fernandina Island, Galapagos. In: Burghardt GM, Rand AS (eds) Iguanas of the World, Noyes Publ, New Jersey, USA, pp 342–365
Wiley RH (1974) Evolution of social organization and life-history patterns among grouse. Quart Rev Biol 49:201–227
Zar JH (1974) Biostatistical analysis. Prentice-Hall, New Jersey
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Shine, R. Sexual differences in morphology and niche utilization in an aquatic snake, Acrochordus arafurae . Oecologia 69, 260–267 (1986). https://doi.org/10.1007/BF00377632
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00377632