This terrestrial anteater is found in tropical moist forest, dry forest, mangroves, swamp and marsh forests, savanna habitats and open grasslands. It has also been reported from the Gran Chaco (Meritt 2008, Noss et al. 2008, Aliaga Rossel et al. 2021), timber plantations (Kreutz et al. 2013), and areas in regeneration after having been used for agriculture and cattle ranching (Martinez et al. 2020). Recent camera trap data suggest that the species may be more abundant in areas of upland forest in the Brazilian Amazon than previously thought (Prestes et al. 2022).

Giant anteaters require large areas (>10 km²) for their survival (Noss et al. 2010), which should contain forested patches (Giroux et al. 2021). Genetic analyses suggest that the Pantanal and Cerrado subpopulations share similar genes (Miranda et al. 2022). The establishment of forested corridors between biomes is thus fundamental for this habitat generalist.

Animals are generally solitary. Once per year, the female gives birth to a single young. Gestation length is 171 to 184 days (Bartmann 1983, Patzl et al. 1998, Knott et al. 2013). The mother carries the offspring on its back for approximately six months. Data from captive animals in European zoos show several females reproducing for the first time at 18-22 months, and the oldest known reproductive captive dams were 20-24 years old (unpublished report provided by I. Schappert). For wild females, sexual maturity is usually indicated as being around 2 years. Population data of wild giant anteaters are limited. A giant anteater baseline population viability model built using multi-data sources estimated the age at first breeding at 2 years, maximum lifespan at 15 years, and generation length at around 7 years (Desbiez et al. 2020).

Myrmecophaga tridactyla has been recorded from northeastern Honduras in Central America, south through the lowlands of South America to the Gran Chaco region of Bolivia, Paraguay and Argentina. Within Central America, the species has disappeared from much of its range, with recent sightings generally confined to highland regions. The giant anteater is considered the most threatened mammal of Central America; it seems to be extinct in Belize, Guatemala, and possibly Costa Rica. It is not listed in Owen and Girón's (2002) checklist of mammals of El Salvador. In South America, this species seems to be extinct in Uruguay (Fallabrino and Castiñeira 2006) and in the state of Santa Catarina, Brazil (Cherem et al. 2004). Its presence in Ecuador west of the Andes needs to be confirmed.

Myrmecophaga tridactyla is listed on Appendix II of CITES. It has been recorded from many protected areas. It is listed on several national Red Data lists, and is protected as a national heritage species in some provinces in Argentina. There is a need to regulate or to improve fire management practices, especially in cattle ranching practices, and within the regions of grassland habitat occupied by this species. Population and genetic data, as well as habitat use information, are needed, especially for areas that are being subjected to land use change.

The species is listed as Regionally Extinct in the Brazilian states of Rio de Janeiro (Bergallo et al. 2000) and Espírito Santo (Chiarello et al. 2007). It is classified as Critically Endangered in Paraná (Instituto Ambiental do Paraná 2010) and in Rio Grande do Sul, Brazil (Fontana et al. 2003). It has been successfully reintroduced in Iberá, Corrientes province, Argentina (Jiménez-Pérez et al. 2016). More recently, a reintroduction program has been initiated by Instituto Tamandua in the Pantanal of Brazil.