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Morphometrics is the quantitative study of organisms shape and size. Intrinsic (e.g. age and sex) and extrinsic (e.g. abiotic conditions) factors can be related to morphological diversity and can aid in the study of species biology and ecology. Giant armadillos have rarely been captured in the wild and very little is known about the species. Here we aimed to characterize body measurements of free-living giant armadillos (Priodontes maximus) in mid-western Brazil and evaluate how these measurements vary between sexes and age classes to gain insights on the species biology and ecology. We captured 28 armadillos in the study area, 18 adults (9 males, 9 females) and 10 subadults (6 males, 4 females) and assessed twenty-five different morphometric measurements for each captured armadillo. To evaluate if age class and sex of adult individuals can be differentiated by a concise set of morphometric measurements we used Linear Discriminant Analyses. We encountered significant morphometric differentiation between age classes and report seven parameters that best discriminate individuals between age classes which may allow the identification of individual's age class in future studies. The wide morphometric variation in subadults could indicate that individuals have a long developmental process between weaning and sexual maturity. Morphometric differentiation between sexes was possible through the association of three morphological parameters and adult males are larger and heavier than females. Although we were limited by the number of animals sampled in previous studies, females presented similar body mass across studied sites, while males presented variation of up to ten kilos across the species distribution. This indicates that the degree of sexual dimorphism can vary among localities and raises interesting ecological questions regarding the species reproductive system. This variation can be related to abiotic factors (e.g. latitude, temperature and topography), differences in productivity among biomes (i.e. resource abundance and distribution), population density, and/or genetic variation between populations and should be explored further. We propose the measurements used here be used as standard measurements for this species since it encompasses all of the most distinctive features of the species and allows a full morphological characterization, enabling the future comparison between populations of this widely distributed species. [ABSTRACT FROM AUTHOR]

The natural history of the southern naked-tailed armadillo Cabassous unicinctus squamicaudis is not well known. Here, we provide basic information about burrow systems, home ranges, activity, morphometric measures, and reproductive behaviour. We monitored 10 individuals through VHF telemetry and direct observations in the central Pantanal of Brazil for 24 months. Males (2.06 km 2 ) had significantly larger home ranges than females (0.59 km 2 ) and home ranges of males overlapped with those of several females. There was very little overlap in ranges of the same sex and very few social interactions were observed. Southern naked-tailed armadillos dug convoluted galleries to forage, and, unless they used their entrance to exit, they emerged on average 2 m away (ranging from 0.01 m to 17 m) from the burrow entrance. When leaving their burrows, they spend on average 6.5 min above ground, travelling an average of 83 m (ranging from 1 m to 781 m) before going back underground. They do not return to sleep in a particular burrow, changing burrows frequently. The studied armadillos were diurnal, and spend 99.25% of the day underground, emerging only during the hottest period of the day (mid-afternoon). The southern naked-tailed armadillos should be classified as a subterranean species, rather than fossorial since they spent most of their time underground where foraging also takes place. Minimum densities of C. u. squamicaudis were estimated at 2.21 adults/km 2 . Gestation was estimated to last for 4 months. Parental care of a single young lasted on average 4 months. Niche overlap between E. sexcinctus and C. u. squamicaudis in the study area is minimal. [ABSTRACT FROM AUTHOR]