Between 1972 and 1982, five giant armadillos (Priodontes maximus) resided for varying periods in an off-exhibit area at the Lincoln Park Zoo in Chicago, Illinois. They included three males which came from Guyana and two females from Bolivia, all received as wild-caught young adults. Together they were the subjects of observations by animal care staff and volunteer docents, who made almost daily observations on the overall activity, food consumption, and general behavior of the giant armadillos. Zoo personnel also recorded weights and body measurements at regular intervals, as well as basic physiologic values such as body temperature and respiratory rates. The presence of Priodontes in the collection stimulated a number of communications, visits and inquiries from individuals and organizations interested in its natural history and behavior. Together with field excursions to giant armadillo habitat in the Chaco of Paraguay and northern Argentina (Meritt, 1973), these captive armadillos prompted the development of a detailed life history outline—one that summarized research questions related to this species, noted information not readily available or missing from the literature, and listed life history traits which are still unknown (Meritt, unpubl. ms.).

A recent field excursion to the Chaco of Paraguay, and an increase in research projects in Argentina and Paraguay, has prompted me to update and expand this outline, which is meant to serve as a guide for those studying this, the largest of the living armadillos (Ceresoli and Fernandez-Duque, 2004; Porini, 1999, 2001). Many of the study topics posed here will only be answered through the detailed study of animals in the wild, but others may be addressed through the diligent observation of animals already held in various Argentine zoos, or those under investigation in private wildlife reserves. It is my hope that anyone intending to work with Priodontes, or those already doing so, will consider the questions raised in this outline. I encourage anyone who is able to provide answers to any of these questions to publish their results; and likewise I welcome any additions to this list, based on the life history and behavior of the giant armadillo.

A thorough search of the literature demonstrates just how little is known about this species. Burmeister ( 1867a, 1867b) provided early anatomical information on the giant armadillo, including notes on its skeleton. Benirschke and Wurster (1969) provided the first chromosome count for this species, while Carter (1983) and Carter and Encarnação (1983) conducted a census of its burrows in the Serra da Canastra, Brazil. Parera (2002) provided a brief review of the status, distribution, habitat and diet of the species in Argentina, but little else is known directly, although some inferences may be made from the related forms of Cabassous and what is known about their natural history and behavior.

One may hypothesize that Priodontes is generally solitary, except during periods of sexual receptivity. While the number of young per litter is unknown, in at least two Cabassous species there is usually only a single offspring (pers. obs.). The gestation period is unknown, but thought to be similar to Cabassous; the period of maternal care is not known, and the role, if any, of the male in the rearing and protection of the young is also unknown. At the Lincoln Park Zoo, captive female Cabassous with developing offspring were not in the company of a male (pers. obs.) so it is not possible to make any inferences about the male's role, or even his possible threat to the offspring. Strikingly, no juvenile Priodontes have been discovered in the field, nor found their way into captive management. Various species of Cabassous have been confused for immature Priodontes at one time or another (pers. obs.) and have even been offered for sale by animal dealers. Whether the evidence is physical or photographic, however, none of these supposed giant armadillos have been proven to be Priodontes. Even in habitat known to support them, where giant armadillo activity has been demonstrated and field studies have been carried out, no young have ever been witnessed.

Our understanding of the habitat preferences of giant armadillos is also imprecise. While the present distribution of Priodontes has been adequately mapped, both individuals and populations are patchy in their distribution, and may be limited to islands of preferred habitat. In the Chaco of Paraguay, for example, where Priodontes is known and occasionally captured, they are most often encountered in riparian habitat or in similar areas with loose, sandy-loam soil. It appears that Priodontes in the Paraguayan Chaco prefers soil with a loose composition and near adequate water supplies, as well as necessary food such as insects, fruit and carrion (pers. obs.). Captive individuals have consumed a variety of meat and meat-based diet formulas (Meritt, 1977). Recent dietary studies have made a significant contribution to identifying the type of insect material sought by Priodontes, and provided additional insights to its habitat requirements in a very different ecosystem, the Cerrado of Brazil (Anacleto and Marinho-Filho, 2001).

Although Priodontes is widespread in its geographic distribution, and found in a variety of tropical ecosystems throughout South America, it is nowhere as common as the range maps would imply. Often only individual animals, rather than populations, are found in what might seem to be prime habitat. For native people across the continent, Priodontes is the armadillo of choice for food whenever available; given its adult mass (as much as 40 kg), one individual makes for a significant source of protein for a subsistence hunter and his family. Thus it is hunted wherever it may be found, and in some habitats it may represent the single largest source of meat (Leeuwenberg, 1997; Meritt, in prep.).

A Checklist of Research Questions for “Tatu Carreta,” “Tatu-Canastra,” the Giant Armadillo (Priodontes maximus)