Local and continental determinants of giant anteater ( Myrmecophaga tridactyla ) abundance: Biome, human and jaguar roles in population regulation

The giant anteater ( Myrmecophaga tridactyla ) is currently found in a wide variety of habitats from Honduras to Argentina. Across this wide range, researchers have postulated that anteater populations are negatively affected by several factors, including hunting, habitat loss and fragmentation, fire, vehicle collisions, and predation by jaguars. But no studies to date have evaluated the relative importance of these factors across sites, either at a regional or continental scale. We used camera traps to analyze variation in giant anteater abundance at two spatial scales. At a regional scale, we conducted camera trap surveys in the dry Chaco of Argentina and used occupancy models to explore the effect of protection status and human accessibility on giant anteaters’ relative abundance. At a continental scale, we used data from 40 camera trap studies (representing 42 different locations) and Generalized Linear Models (GLM) to assess the potential relation of biome, human disturbance and the presence of jaguars on giant anteater camera trap records. In the Argentine Chaco, protection and human disturbance do not significantly affect the proportion of area used by the species. The average anteater records/100 camera days and the proportion of sites used are very high across the study area. At a continental scale, anteaters are more frequently recorded in dry forests than in moist forests. Locations with very high human disturbance have camera trap rates that are 5–10 times lower compared to intermediate or low disturbance locations. Finally, giant anteater capture frequency increases up to 70% where jaguars are absent. Dry biomes and intermediate levels of human disturbance may favor anteaters by providing greater habitat heterogeneity coupled with a lower jaguar abundance. This may explain the relatively high abundance of giant anteaters in the Argentine Chaco. However, growing human populations, the advancing agriculture-livestock frontier, and an expanding road network may in time eliminate giant anteaters from most of this region.