The giant armadillo (Priodontes maximus) shares a common ancestor with the extinct glyptodonts within the order Cingulata. The latter developed gigantism and complete armour, reaching up to 4 m in length and 1.5 tonnes in weight—dimensions that, although imposing, did not exempt them from predation by Pleistocene superpredators such as the saber-toothed cat (Smilodon populator), the giant short-faced bear (Arctotherium angustidens), and large felids similar to the jaguar. P. maximus, by contrast, maintained a considerable size (up to 1.6 m and >50 kg) but evolved into a segmented, flexible carapace, active digging habits, and a myrmecophagous diet. Today, its main natural predators are the jaguar (Panthera onca) and the puma (Puma concolor), although human pressure—through hunting and habitat loss—constitutes its greatest threat. Morphological and genetic studies confirm that glyptodonts form a clade derived from modern armadillos, placing P. maximus among their closest living relatives. Its survival beyond the Pleistocene extinction is due to its trophic flexibility, nocturnal activity, and burrow use—traits that remain key to evading predators and withstanding current anthropogenic pressures.
A Specialist with Flexibility
Specialist yet adaptable, the giant armadillo bases about 90% of its diet on ants and termites, although it occasionally incorporates small vertebrates, eggs, roots, or fallen fruits. To obtain food, it relies on exceptional adaptations: hypertrophied foreclaws—particularly the third, which can measure over 15 cm and break through termite mounds hardened like cement or rip apart rotting logs; a cylindrical, muscular, mucus-coated tongue, capable of extending up to 60 cm and projecting rapidly into narrow tunnels; and conical papillae along with viscous saliva that function like a brush, trapping hundreds of insects with each insertion. Under optimal conditions, it can capture more than 50,000 insects in a single night—an energy efficiency crucial for a large-bodied animal with a specialised diet. This combination of strength, reach, and precision allows it to feed even in adverse seasons, and its ability to include occasional foods outside its main diet has been fundamental for its persistence across thousands of years of climatic change and human pressure.
Burrows: Underground Architecture that Sustains Life
The burrows of Priodontes maximus are elliptical underground structures (30–45 cm in diameter) with tunnels ranging 3–5 m in length and up to 1.5 m deep, ending in resting chambers with stable temperature and humidity. Their orientation minimises solar exposure, optimises ventilation, and reduces the risk of flooding. Excavation, carried out with hypertrophied foreclaws, can move up to 200 kg of soil in a single night, leaving characteristic mounds at the entrance. These shelters, used for decades, are reused by more than 70 vertebrate and invertebrate species, acting as microclimates in dry zones and elevated refuges in floodplains. At the Guayabero Cocodrilo Reserve, camera traps have documented their use by rodents, opossums, tamanduas, tayras, agoutis, Tupinambis teguixin, and other small mammals, confirming the giant armadillo’s role as a key ecosystem engineer.
Slow Reproduction, High Risk
The giant armadillo exhibits one of the lowest reproductive rates among large mammals, with a single offspring per litter after a gestation of ~120 days, usually beginning at the onset of the rainy season. Its population density, below 0.4 individuals/km², combined with the need for vast continuous habitat, limits gene flow and increases the risk of local extinction. Classified as Vulnerable by the IUCN, it faces threats from habitat loss and fragmentation, illegal hunting, and low reproductive productivity. At the Guayabero Cocodrilo Reserve (La Macarena, Meta), it has been recorded in the high rocky sector, characterised by well-drained gravelly soils and low tree cover; during the rainy season, it migrates from low floodable areas to excavate burrows that remain active for weeks or months.
Why Studying It Means Protecting It
Monitoring P. maximus goes beyond research: it is a direct conservation tool. Each recorded burrow provides key information on its ecology—from sheltering patterns to critical survival areas—and enables the design of more effective management and restoration plans, the strengthening of protected areas, and community awareness about the importance of conserving this subterranean giant. In a context where large mammals are disappearing at an accelerated pace, protecting Priodontes maximus means safeguarding a unique chapter of South America’s evolutionary history and maintaining the functional balance of Amazonian ecosystems.
References
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