Fitzgerald, LA, JM Chani, and OE Donadio

Fitzgerald, L.A., J.M. Chani, and O.E. Donadio. 1991. Tupinambis lizards in Argentina: Implementing management of a traditionally exploited resource. Pages 303-316 in Robinson, J. and K. Redford, eds. “Neotropical Wildlife: Use and Conservation”. University of Chicago Press, Chicago, USA. Current Address: Texas A&M University College of Agriculture & Life Sciences Dept. of Wildlife and Fisheries Sciences 210 Nagle Hall College Station, Texas 77843-2258 21 Tupinambis Lizards in Argentina: Implementing Management of a ~aditionally Exploited Resource LEE A. FITZGERALD, Jos~ MARIA CHANI, AND OSCAR E. DONADio 1\vo speciesof tegu lizards of the generaTupinambis, 1: teguixin, and 1: rufescens (fig. 21.1), are heavily exploited for their skins in Argentina. Each year, more than 1,250,000 skins are exportedfrom Argentina to the United States, Canada,Mexico, Hong Kong, Japan, and severalEuropean countries. Some skins are reexportedor madeinto exotic leatheraccessories, but the majority of the tegus are destinedto becomecowboy boots in Texas(Hemley 1984a).Sur- prisingly, the trade has continued at this level for at least 10 years (Hemley 1984a:Norman 1987). An internal Argentine market also exists foltegu skins, but it hasnot beenquantified. The large trade in Tupinambishas causedconcern among some government and nongovernmentorganizations because the biology of the lizards is essen- tially undescribed,and the effectson the tegu populationsand associatedbiotic communitiesof removing more than one million individuals annually are un- known. Although population declineshave not beendocumented, it seemspru- dent to study Tupinambisbiology and formulate long-term managementand conservationplans if the ecological, economic, and cultural valuesof the re- sourceare to be guaranteed. The Tupinambistrade is important to the Argentine economy.The export valueof the resourceis worth millions of dollars annually,and for rural peoples in northern Argentina with low wagesor intermittent employment,tegu hunting is a significant sourceof income. In the vicinity of Joaquinv: Gonzalez, Salta, where we concentratedfield work in 1987-88, hundredsof peoplehunt tegus, and the sale of each skin (about U.S. $4) is equivalentto a day's wages for a farm hand. Additionally, abouthalf the families eat the meat, and tegu fat is highly valuedfor medicinal purposes(Donadio and Gallardo 1984). This project was funded by the World Wildlife Fund-US (WWF-US), the Conventionon International Trade of EndangeredSpecies of Flora and Fauna (CITES), and the Camarade Industrialesde Curtidoresde Reptilesde Argen- tina (CICuR) with the aim of describingthe populationbiology and ecology of 303 304 Lee A. Fitzgerald,Jose M. Chani, and OscarE. DonadIo Figure 21.1. A juvenile (approximately 280 mm SVL) Tupinambis teguixin, the common tegu top) and an adult male (approximately 430 mm) Tupinambis rufescens, the red tegu (below). (Photo, Larry E. Naylor) Tupinambisin Argentina. The project is unusualin that the reptile skin traders, who benefit the most from exploiting the lizards, finance the majority of the project. Hopefully, the Tupinambisproject will serve as a model for funding other studiesof naturalresources in Latin America. The long-term goals of the project are to determinethe factorsnecessary to ensurethe conservationand rational use of Argentine Tupinambispopulations TupinambisLizards in Argentina 305 and develop a workable management scheme. To achieve this goal, we have begun studies of Tupinambis reproductive biology, behavior, demography, hab- itat use, activity patterns, growth rates, diet, morphology, and hunting meth- ods. In this chapter we elucidate the relationships between Tupinambis natural history and the present exploitation system and explore the implications of these relationships for Tupinambis management and conservation. We present results from the first 6 months of field work and finally we outline future research and potential management approaches. Distribution and Natural History of Tupinambis in Argentina Tupinambis systematics are unresolved, but at least three, and possibly other Tupinambis species occur throughout South America east of the Andes (Presch 1973; Gudynas 1985). In Argentina, 7: teguixin, the common tegu, occurs in the provinces of Mi- siones, Corrientes, eastern Formosa, Entre Rios, eastern Chaco, Santa Fe, southeastern C6rdoba, eastern La Pampa, and Buenos Aires (Presch 1973; Donadio 1984) (fig. 21.2). 7: rufescens, the red tegu, occurs in the northwest- ern part of the country, in the provinces of Salta, Jujuy, western Chaco, western Formosa, Santiago del Estero, eastern Thcuman, San Juan, Mendoza, and as far south as northeastern Patagonia (Cei and Scolaro 1982) (fig. 21.2). The distribution of 7: rufescens extends into the Paraguayan and Bolivian Chaco, some arid parts of eastern Paraguay, and southern and southeastern Brazil (Presch 1973; Norman 1986). Both species may occur sympatrically in eastern Para- guay (Presch 1973; Norman 1986) and in the provinces of Chaco, Formosa, and Santiago del Estero, Argentina. Tupinambis rufescens is a more arid land species than 7: teguixin. but within their ranges both species use a variety of habitats, including primary forest, disturbed and regenerating forest, fence rows, and shelter belts between plowed fields. They are capable of excavating their own burrows, but commonly take refuge in burrows made by other animals or in natural cavities. Tegus are om- nivorous, including carrion and fruit in their diets as well as snails, insects, and small vertebrates (Gudynas 1981; Dessem 1985). Tupinambis are the largest members of the Teiidae; males of both species can exceed 500 mm snout-vent length (SVL) (1300 mm total length) and weigh up to 4.7 kg (unpubl. data). Tupinambis exhibit sexual dimorphism in that adult males are longer and heavier than females on average, with wider heads and enlarged jaw musculature. Male tegus also possess two "buttons" of enlarged scales in the postanal region. With preliminary data from wild and captive populations, we have as- sembled a fairly clear picture of tegu breeding chronology in Argentina. Both species overwinter in burrows and emerge during the first hot days in Septem- ber and October. Tupinambis teguixin mates from September through early Jan- 306 Lee A. Fitzgerald,Jose M. Chani, and OscarE. Donadio Figure 21.2. Estimated distribu- tions of Tupinambis teguixin and 7: rufescens in Argentina. The provinces where commercial tegu harvests were authorized at the time of writing are num- bered: 1 = Salta; 2 = Formosa; 3 = Chaco; 4 = Santiago del Estero. uary, and in the dry chaco7: rufescensstarts breeding a few weekslater, prob- ably depending on the start of the rainy season(fig. 21.3). In captivity at GuaycolecReserve, Formosa, of thirty male and thirty female 7: teguixin that had opportunitiesto mate, only large individuals did so. Small maleswere re- jected by breeding females, and small females would not copulate. Five suc- cessfully breeding males averaged438 mm SVL, with an averageweight of Tupinambis Lizards in Argentina 307 MALES FE MALES ---~~.-.~~::~~~~ .-.~~::~ - SEPT OCT NOV DEC JAN FEB MAR APR MATING OBSERVED TERRITORIALITY AND AGGRESSIVENESS REDUCED ACTIVITY AND WEIGHT GAIN NESTING AND NEST ATTENDANCE -.'-"'-" LITTLE OR NO FORAGING - - - - HATCHLINGS IN NESTING BURROW Figure 21.3. A chronogram of reproductive and postbreeding behaviors observed in a captive population of Tupinambis teguixin at Guaycolec Reserve. Formosa. The same trends were observed in the wild at National Park El Palmar, Entre Rios. 3,759 g, whereasthe five breedingfemales averaged 382 mm SVL andweighed 2,263 g. Nesting begins in mid-Novemberand peaksin December,but occasionally gravid femalescan be found as late as February.Females of both speciescon- struct nestsout of moist grass,small sticks, and miscellaneouslitter in burrows. Tupinambis teguixin laid twenty-nine to thirty-nine (n = 5; i = 33.75) eggs at Guaycolec,and clutch sizesof twenty to fifty-four were reportedby Donadio and Gallardo (1984). Two nestsof 7: rufescensfrom the wild containedtwenty- five and twenty-four eggs, but clutch sizesgreater than thirty are known (pers. obs.). After the incubation period of 45 to 75 days, young hatch from late De- cemberthrough March (fig. 21.3). Interestingly,females remain with their neststhroughout the incubationpe- riod, possibly to provide protection. Hunters claim that femalesattend nests, and this has been the case with nests we have excavated.At the Guaycolec facility, females remained near their nesting burrows once nests were con- structed, and nesting females were noticeably aggressivetowards intruders. Hatchlings remain for at least a few weeksin the nestingburrow with the fe- 308 Lee A. Fitzgerald,Jose M. Chani, and OscarE. Donadio male. Whetherparental care is involved in this relationship,whether the mother and young overwinter together, and the effects of maternal presenceon off- spring survival are topics of current and future research. Observationsat El Palmar National Park indicate that during the courting period, tegusroam over relatively large homeranges, and much fighting ensues betweenmales. Males frequentlymark alongtrails and aroundthe burrowsthey visit by rubbing their thighs, tails, and cloacasalong the ground, presumably leaving behind secretionsfrom the femoral pores and cloaca. Femalesalso leave marks but much less frequently than males. We observedsuch marking behaviorsboth in captivity and in the wild at El PalmarNational Park.

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