Combat behaviour in the Fence Skink Cryptoblepharus virgatus (Garman, 1901).
By Rob Valentic.
An adult Striped Snake-eyed Skink Cryptoblepharus virgatus from Cardwell, north-eastern Queensland, Australia.
One doesn’t need to be trekking through a remote sandstone gorge in the Kimberley or crawling through a dark cavern in the Black Mountain to make herpetological observations. The following report is a perfect case in point and was taken while I was eating a hamburger with the lot outside a take-away food store in coastal Queensland.
Location: Pacific Palms Caravan Park, Bruce Highway, Cardwell (18°16’S, 146°1’E).DISCUSSION
Date: 29th March 1994.
Time: 12:45hrs (Eastern Standard Time).
Weather Conditions: 27°C, 50% cloud cover (approx.), slight onshore breeze.
Notes: Three adult Cryptoblepharus virgatus were sighted perched on a vertical wooden power pole about 1 metre above pavement level. One skink began to descend the pole with a second skink in pursuit. Combat was observed on the concrete pavement immediately adjacent the pole. The skinks aligned parallel to one another and simultaneously initiated rhythmic tail-waving movements that are conspicuous amongst skinks of the Carlia genus (pers. obs.). Both lizards appeared limp and listless, their bodies quivering spasmodically. The skink which gave chase bit the opponent twice - to the jaw and to the trunk of the body - twisting violently on both occasions. These bites resulted in a hasty ascent of the pole, the victor again giving chase. The third lizard which had remained on the pole during this interaction was then subjected to harassment by the aggressor which involved repeated attempts to bite its hindquarters whilst it tried to escape.
C. virgatus are territorial and establish home ranges as juveniles (Stammer, 1988). The sex of C. virgatus cannot be visually determined (Ehmann, 1992), ruling out speculation of male combat. I assume the combat was related to territory. Torr (1994) documents an incident of combat in Carlia rubrigularis where the aggressor chased away a third (juvenile) skink after combat. This is similar to the incident described above. The postural observations above are significant in that they differ from the other reports in the literature; Carlia rubrigularis and C. rostralis (flattening considerably and orientating dorsal surfaces towards one another) as documented by Torr (1994) and Whittier and Martin (1992); Lampropholis guichenoti (neck-arching behaviour) as documented by Done and Heatwole (1977) and Torr (1990; cited in Torr, 1994). Griffiths, (1987 p.86) shows an interesting photograph of four adult L. guichenoti engaged in combat simultaneously.
The report above gives further evidence of the high behavioural diversity within the Scincidae (Torr, 1994; Torr and Shine, 1994). Whether this observed combat display in C. virgatus is ritualistic warrants further investigation.
Done, B.S. and Heatwole, H. 1977. Social behaviour of some Australian Skinks. Copeia: 419-430.
Ehmann, H. 1992. Encyclopedia of Australian Animals - Reptiles. Angus and Robertson, Sydney. 495pp.
Griffiths, K. 1987. Reptiles of the Sydney Region. Three Sisters Productions Pty Ltd, Winmalee N.S.W. 120pp.
Stammer, D. 1988. Hatching and home range activities in juvenile Cryptoblepharus virgatus. Herpetofauna 18(2): 23-24.
Torr, G.A. and Shine, R. 1994. An ethogram for the small scincid lizard Lampropholis guichenoti. Amphibia - Reptilia 15: 21-34.
Torr, G.A. 1994. Combat behaviour in the rainforest skink Carlia rubrigularis. Herpetofauna 24(2): 40.
Whittier, J.M. and Martin, J. 1992. Aspects of social behaviour and dominance in male rainbow skinks, Carlia rostralis. Aust. J. Zool. 40: 73-79.