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This paper presents unique data on the reproductive behavior of the rare giant armadillo (Priodontes maximus), including gestation, inter-birth intervals, number of offspring and parental care. It also describes a potential non-parental infanticide. The study used telemetry, camera traps and track observations for over 7 years in a 300-km2 area in the central Brazilian Pantanal. Females with young were recorded 5 times. Reproductive events did not appear to be seasonal. A 5-month gestation period was estimated. Parental care is long, as the offspring is completely dependent on its mother's milk until 6–8 months of age. Weaning was estimated to occur at 11–12 months, but the offspring continued to be dependent on its mother's burrows until 18 months old. Three births were recorded over a 6-year period for one individual. The offspring from the first birth recorded was killed at 4 weeks of age in a potential infanticide, but 7 months after the first birth, a second offspring was born. A third birth was recorded 3 years after the second birth. Results from this study suggest that the population growth rate of giant armadillos is very low and the species can therefore easily be locally extirpated. [ABSTRACT FROM AUTHOR]

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]

The giant armadillo (Priodontes maximus) is the largest living armadillo and is classified as Vulnerable by the International Union for Conservation of Nature. Little is known about the species biology and especially its reproduction. However, data such as the age at sexual maturity are employed for estimation of a species generation length, which is an important parameter for extinction risk assessment. Thus, the aim of this study is to estimate the age at sexual maturity for male P. maximus in the wild and to predict generation length for this species. During a long-term in situ study, eight male P. maximus were captured for reproductive evaluation considering both morphometric characteristics (e.g. body, penis and testes dimensions), and data on sperm production (assessed by electroejaculation). Based on observations of this study, it is estimated that male P. maximus reach sexual maturity at an age of 6.5–8 years. This is at least 5.5–7 years later than previously published. Consequently, generation length for P. maximus results in 11 years when applying standard formula including age at sexual maturity in males and an estimate of age at last reproduction of 20 years. However, the generation length is probably underestimated here as sexual maturity in females and age at last reproduction could be later than estimates used. Even these conservative estimates result in noticeable change for the timeframe used in extinction risk assessments for this species as it is 33 instead of 21 years. Thus, results from this study might affect the classification status of P. maximus particularly for regional assessments. [ABSTRACT FROM AUTHOR]