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(mean = 0.758 g). In the vivarium, the fiveneonates coexisted without any evident conflictbetween them, or between the two females and oneadult male, and willingly fed on small insects.Days after, both females and young were returnedalive to the site where the adults had beencaptured.

ACKNOWLEDGEMENTSWe are grateful to the Administración de ParquesNacionales, Argentina; Alejandro Carrizo, SanGuillermo park guard; and the UniversidadNacional de Córdoba (SeCyT-UNC) andCONICET for financial support to MRC.

REFERENCES

Blackburn, D. G. (1993). Standardized criteria forthe recognition of reproductive modes inSquamate reptiles. Herpetologica 49, 118–132.

Cei, J. M. (1986). Reptiles del centro, centro-oestey sur de la Argentina. Mus. Reg. Scienze Nat.Torino, Monogr. 4, 1–527.

Cei, J. M., Etheridge, R. & Videla, F. (1983).Especies nuevas de iguánidos del noroeste de laprovincia de San Juan (Reserva provincial SanGuillermo), Argentina. Deserta 7, 316–323.

Chébez, J. C., Rey, N. R. & Williams, J. D. (2005).Reptiles de los parques nacionales de laArgentina. Buenos Aires: L.O.L.A., 75 pp.

Fitch, H. S. (1970). Reproductive cycles in lizardsand snakes. Univ. Kansas Mus. Nat. Hist., Misc.Publ. 52, 1–247.

Pianka, E. R. & Vitt, L. J. (2003). Lizards.Windows to the evolution of diversity. Berkeley& Los Angeles: University of California Press.333 pp.

MARIO R. CABRERA1* and JULIO C.MONGUILLOT2

1 Departamento Diversidad Biológica y Ecología,Universidad Nacional de Córdoba, Velez Sarsfield299, (5000) Córdoba, Argentina.

² Delegación Regional Centro, Administración deParques Nacionales, Avenida Richieri 2298,(5000) Córdoba, Argentina.

* Corresponding author: mcabrera@efn.uncor.ed

VARANUS SALVATOR (Water monitor):INTRA-SPECIFIC AGGRESSION. Intra-specific aggression in lizards is well known,particularly in males. In monitor lizards(Varanus spp) it is believed to occur for a varietyof reasons, usually over resources - food,shelters and access to females for males (Horn etal., 1994). Here we describe a brief observationof intra-specific conflict in V. salvator atHettipola, Central Province, Sri Lanka. Theobservations were in made during July 2005 atthe locality described in a recent note (Jolley andMeek, 2006). Each morning, from around 7amlocal time, we regularly observed up to at leastsix large V. salvator foraging or basking in acanalised waterway of less than 0.5 km. Allindividuals observed were approximately 2metres in total length, indicating mature animals(e.g. Andrews, 1995; Bennett, 1998). Baskingwas common at this time of day (dry season)with daily operative temperatures usually above40°C and although we never measured watertemperature, we estimate this was around 20-25oC at the time.

At approximately 07:30 h local time, a large V.salvator swimming along the waterway was seento come into contact with another individual,almost as large, basking on the bank (Fig. 1).The lizard in the water approached the baskinglizard very slowly and at a distance of around ametre emerged and attacked the second lizard.The photograph in Fig. 2 was taken just beforethe attack. Unfortunately, the actual speed atwhich the incident occurred made it difficult fordetailed observations – we could not, forexample, ascertain whether biting was involved,but the basking lizard quickly retreated into thewater and submerged. The larger animal alsoreturned to the water but remained swimming onthe surface and appeared to be looking for theother animal, which we never saw resurface.Within 15 minutes or so of the incident anotherof our research group, John Drake, prompted byour observations, returned to the locality (lessthan 3 minutes walk from our base), andrecorded and photographed combat behaviour

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between two large V. salvator. The lizards werein the water in a typical horizontal embrace butalso reared up out of the water in a bipedalposture. Photographs of this incident can be seenon the Knuckles Expedition Internet Site, wwwhoona. co. uk. However, we cannot be certainthey were same lizards as those in the incidentwe observed.

The narrow waterway combined with highoperative temperatures may have had acontributing effect to the incidents, making itdifficult for the lizards to avoid contact. Forexample, our observations of foraging (dryseason) indicated that this was generally anaquatic activity with brief excursions onto thebank, whereas in much cooler overcast weatherduring the rainy season at Kandy Lake, it waslargely terrestrial, with entry into the waterseemingly only to cross to the opposite bank.Conflict and/or combat behaviour is known in

V. salvator but is usually a terrestrial activity,with apparently no previous reports of itsoccurrence in water (review in Bennett, 1998).Additionally, monitor lizards are notoriouslydifficult to sex, even at close inspection, and sowe cannot be sure of the sexes of the lizardsinvolved. Defence of territory between males orconflict over basking sites (Bennet, 1998) areobvious suggestions, but female defence of anesting area is a further possibility. This isknown in females from several Varanids (Horn,1999) and V. salvator is known to nest in waterbanks and can be aggressive just prior to egglaying (Bennet, 1998). Interestingly, incaptivity, combat behaviour has been observedbetween both males and females as well asbetween females, usually over basking sites ornest boxes (Wicker et al., 1999).

ACKNOWLEDGEMENTS

Permission to carry out the field studies wasgranted by the Forest Department and Departmentof Wildlife Conservation, Sri Lanka. The

Figure 2. Combat behaviour in V. salvator. Following aslow approach to the basking lizard, the animal in the wateris just about to launch its attack. Photograph © E. Jolley.

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observations form part of Project Knuckles whichwas partly operated and partly funded by theUniversity of Edinburgh, Scotland and organisedby Suraj Goonewardene and Anslem De Silva.

REFERENCES

Andrews, H. V. (1995). Sexual maturation inVaranus salvator (Laurenti, 1768), with noteson growth and reproductive effort. Herpetol.J. 5, 189–194.

Bennett, D. (1998). Monitor Lizards; NaturalHistory, Biology and Husbandry. EditionChimaira, Andreas S. Brahm: Frankfurt amMain.

Horn, H. G. (1999). Evolutionary efficiencyand success in monitors: a survey onbehaviour and behavioural strategies andsome comments. In Advances in MonitorResearch II. Horn, H. & Bohme, W (Eds.).Mertensiella 11, 167–180.

Horne, H.G., Gaulke, M. & Bohme, W. (1994).New data on ritualised combats in monitorlizards (Sauria: Varanidae) with remarks ontheir function and phylogenetic implications.Zool. Garten N.F. 64, 265–280.

Jolley, E. & Meek. R. (2006). Natural HistoryNote. Varanus bengalensis (Bengal monitor):Unusual behaviour and feeding. Herp.Bulletin 95, 31- 32.

Rese, R. (1986). Der Kommentkampf beiVaranus salvator. Sauria 8, 27–29.

Wicker, R., Gaulke, M. & Horn, H.G. (1999).Contributions to the biology, keeping andbreeding of the Mindanao Water Monitor(Varanus s. cumingi). In: Advances inMonitor Research II. Horn, H. & Bohme, W.(Eds.). Mertensiella 11, 213–223.

EDIE JOLLEY1 and ROGER MEEK2

1 16 Mountfields, Halifax, West Yorkshire, U. K.Email: ediejolley@yahoo.co.uk

2 7 Rue Georges Clemenceau, Chasnais, France.Email:Rogermeek85@aol.com

PHILODRYAS PATAGONIENSIS (Parelheira):VENOMOUS SNAKE A (CROTALID) ASPREY. Philodryas patagoniensis is found almosteverywhere in South America. In Brazil, it can befound in the states of Pernanbuco and Bahia(Northeast Region), Minas Gerais, Rio de Janeiroand São Paulo (Southeast Region) and in Paranaand Rio Grande do Sul (South Region) (Peters &Orejas-Miranda, 1986) where it occurs primarilyin open areas, but also woodland (Thomas, 1976).Philodryas patagoniensis is a medium-sizedcolubrid snake (Figure 1.) with predominantlyterrestrial, diurnal habits (Marques et al., 2001)that feeds on frogs, lizards, birds, mice, and othersnakes (Duarte & Eterovic, 2003; Perroni, 2004;Hartmann & Marques, 2005). However, availablereports limit it to the ingestion of colubrids, suchas Philodryas olfersii, Thamnodynastes strigatus,Clelia occipitolutea, Liophis poecilogyrus,Liophis jaegeri, Helicops carinicaudus, Lystrophisdorbignyi (Lema et al., 1983) and Liophispoecilogyrus and Pseudablabes agassizii(Hartmann & Marques, 2005). Perroni (2004)found dorsal and ventral scales of a non-identifiedcolubrid on his analysis. According to Shine(1991) ophiophagus snakes can possibly showcannibalism. In the genus Philodryas this has beenconfirmed by Lema (1983) and by Hartmann &Marques (2005), with one report of cannibalismeach. In captivity, a newborn P.patagoniensis wasobserved ingesting another conspecific newbornby attacking and ingesting it head-first. Philodryasolfersii, despite being a non-venomous snake, hasenlarged maxillary fangs in addition to aDuvernoy`s gland (which produces toxicsubstances), and is thus potentially bale toenvenomate its prey (Silvia Cardoso, personalobservation).

We analyzed gut contents from the digestivetract of one female Philodryas patagoniensis sentto us on April 24th 2003 from Santana de Parnaíba- SP (23° 26’S. 46° 56’W), measuring 525 mm insnout-vent length (SVL), 190 mm in tail length(TL), 14.2 mm in head length (HL) and weighing35 g. After examining the feaces of this individual,we verified the presence of a grooved fang whichbelonged to a venomous snake, probably a youngone. By comparing it with the fangs of othervenomous snakes born in captivity, in order to

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