Date of Award

12-2007

Degree Type

Dissertation

Degree Name

Ph.D.

Degree Program

Conservation Biology

Department

Biological Sciences

Major Professor

Bavister, Barry D.

Second Advisor

Pinter, Aelita

Third Advisor

Aguilar, Roberto

Fourth Advisor

Anthony, Nicola

Fifth Advisor

Boily, Patrice

Abstract

The pichi Zaedyus pichiy (Xenarthra, Dasypodidae) is a poorly known, diurnal armadillo inhabiting arid and semi-arid regions of Argentina and Chile that has endured substantial population declines. My objective was to elucidate different aspects of the natural history of Z. pichiy as a first step towards establishing a conservation plan. Wild and captive pichis were studied. Body temperature of wild pichis averaged 35.2±1.2 °C and was highly variable (range 32.2 – 38.3 °C). Temperature measurements of semi-captive males showed that pichis can survive energetically challenging periods by entering hibernation or daily torpor. Stomach contents of poached animals revealed that pichis feed predominantly on insects but also ingest plant material, vertebrates and arachnids. This opportunistic, omnivorous feeding strategy allows them to thrive where food type and availability vary seasonally. The reproductive cycle of pichis was studied by means of histological and fecal hormone analyses. Pichis are seasonal breeders that produce one yearly litter of 1 to 2 offspring, and the initiator of breeding season seems to be an increase in daylength. The absence of regular estrous cycles and corpora lutea in non-pregnant females, and immediate mating attempts after pairing, all suggest that pichis are induced ovulators. Clinical examinations and hematological, serological and coproparasitological analyses of free-ranging pichis, and necropsies and histological examinations of confiscated pichis and roadkills, indicate that the populations are currently in good health. While parasites were often found, no severe pathologies were observed. Infections with potentially zoonotic diseases were rare: only a few pichis were seropositive for Trypanosoma cruzi, none had antibodies against Toxoplasma gondii, and none of the histologically examined individuals presented lesions attributable to these pathogens. Elevated ambient humidity levels often caused moist dermatitis with epidermal detachment in captive pichis. Poaching is currently considered to have a much higher negative impact on the wild populations than disease epidemics. Mortality due to heavy poaching activity may be difficult, if not impossible, to compensate by the current birth rates. This preliminary database on the natural history and reproduction of pichis will assist efforts to conserve this little-known species of armadillo.

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The University of New Orleans and its agents retain the non-exclusive license to archive and make accessible this dissertation or thesis in whole or in part in all forms of media, now or hereafter known. The author retains all other ownership rights to the copyright of the thesis or dissertation.

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