The Screaming Hairy Armadillo Chaetophractus vellerosus is primarily found in xeric environments, in lowland and upland areas as well as high altitude grasslands with loose sandy soils and sand dunes. It also has been recorded from rangeland pasture and agricultural areas. In Buenos Aires province this armadillo lives on sandy-calcareous soils and prefers grasslands with low vegetation and high vegetation cover (Abba et al. 2011). This omnivorous animal constructs burrows and therefore is absent from rocky areas where burrows cannot be excavated (Greegor 1985, Abba et al. 2007, 2011, 2023, Abba and Cassini 2008, Pérez Zubieta 2008, 2011). 

In Bolivia, Screaming Hairy Armadillos in the high Andeans use crop areas (potatoes) while searching for food, while sand dunes are vital for their survival because they use them for burrow construction and foraging (Pérez Zubieta 2011).

The estimated home range size is 3.4 ha in Catamarca, Argentina (Greegor 1980) and 1 to 5.3 ha in Buenos Aires province, Argentina (Glaz and Carlini 1999). Pagnutti et al. (2014) described seasonal differences in home range size in a closed population in Buenos Aires province, Argentina: in fall-winter, home range size was 0.23 ha and 0.27 ha in males and females, respectively, while it was 0.75 and 0.13 ha, respectively, during spring-summer. In this population, the spatial distribution of C. vellerosus was aggregated and possibly influenced by land use (Pagnutti et al. 2014).

Densities of 0.58 animals/km² have been observed in Kaa-Iya National Park, Bolivia (Cuéllar 2008). Peredo (1999) estimated a total population of 13,000 individuals in an area of 340 km² in Bolivia and A. M. Abba (pers. comm. 2024) found around 0.6 individuals/ha in some parts of the east of Buenos Aires Province, Argentina.

During the cold season, Screaming Hairy Armadillos are mainly active at noon and the early afternoon, while in warm seasons their activity period shifts to the afternoon and night (Greegor 1980, Abba et al. 2011). However, their activity seems to be diurnal throughout the year at high altitudes (Zúñiga and Araya 2014). 

The diet of C. vellerosus is mainly composed of beetles (larvae and adults), butterfly larvae, plant matter and small vertebrates (Greegor 1980, Soibelzon et al. 2007, Abba et al. 2011, 2019).

C. vellerosus is a seasonal breeder. Its reproductive season lasts from September to January in Buenos Aires province (Abba et al. 2011, Abba 2020) and November to January in Bolivia (Cuéllar 2008). One to two offspring per litter are born inside the burrow after a gestation period of 60 days. Offspring remain inside the burrow during the entire lactation and start emerging in January-February. Generation length of the subpopulation in eastern Buenos Aires Province has been estimated at 3.2 years (Abba 2020).

Chaetophractus vellerosus is generally known from the Chaco region of Bolivia (Cuéllar and Noss 2003, Noss et al. 2010), Paraguay and Argentina (Gardner 2005, Abba et al. 2012, Superina and Abba 2018). A disjunct population occurs in eastern Buenos Aires Province, Argentina (Crespo 1974, Carlini and Vizcaíno 1987, Abba et al. 2007, 2011, 2023; Abba and Cassini 2008). Recent studies have confirmed that C. nationi is an invalid species and a synonym of C. vellerosus (Abba et al. 2015, Gibb et al. 2016). Hence, the distribution of C. vellerosus now also includes the high altitudes of Chile (Arica y Parinacota, Antofagasta, Tarapacá), Bolivia (sand dunes in Oruro and Potosi) and Argentina. Its presence in Peru is uncertain. Pacheco et al. (2021) do not include it in their most recent list of the mammals of Peru, while Cossios (2013) reports that interviews with locals suggest that the species is present in southern Puno department. The species occurs at altitudes from sea level to 4,600 m asl.

Chaetophractus vellerosus is present in a number of protected areas, including the Kaa-Iya National Park in Santa Cruz,  Bolivia, in 13 protected areas of Argentina (https://sib.gob.ar/especies/chaetophractus-vellerosus), and in several protected areas in the Paraguayan Chaco (Smith and Ríos 2018). The high-altitude animals are present in the Sajama National Park, Bolivia, and in Lauca National Park, Las Vicuñas National Reserve and Volcán Isluga National Park in Chile (Pasutti 2017).

The species is listed as Least Concern at the national level in Argentina (Abba et al. 2019) and Paraguay (Saldivar et al. 2017), and as Endangered in Bolivia for the Andean population (Perez-Zubieta et al. 2009). In Chile, where only the high-altitude armadillos occur, it is listed as Vulnerable under criterion B2ab(iii) (Pasutti and Superina 2019).

The high-altitude armadillos, formerly known as C. nationi, were previously listed as globally Vulnerable (VU A2acd; IUCN 2014). They are still listed as C. nationi in Bolivia and Peru, where they are considered Endangered (Pérez-Zubieta et al. 2009, Cossios 2018), although its presence in Peru is uncertain.

The subpopulation in eastern Buenos Aires province, Argentina, is categorized as Endangered at the national level (Abba et al. 2019).

In spite of the taxonomic change, the species is still listed as C. nationi in CITES Appendix II (CITES 2023), which establishes a zero annual exportation quota for this species due to its traditional use (Peredo 1999).

These animals are considered emblematic of the Bolivian highlands, particularly from the Oruro department (Cáceres 2004) where they are closely linked to the cultural heritage. In 2015, the Bolivian government made it illegal to sell or possess a new matraca. Therefore, old matracas were registered for all dancers in 2019 (Aliaga Rossel et al. 2021). The agreement seeks to prevent, catalogue, regulate, replace, and eliminate the use of wildlife specimens (Aliaga-Rossel et al. 2021). In April 2022, a national law (1424) declared the Andean Hairy Armadillo C. nationi as a Natural Heritage of the country, prioritizing the protection, conservation and defence of the species and its habitat.