Biology Reference
In-Depth Information
coming from a burrow. They crawled in and pulled out a sleeping giant armadillo. Leandro
Silveira also had an anecdotal encounter. But that was the extent of giant armadillo natural
history—a few paragraphs.
These three rare mammals can all be described as unusual looking. So one might wonder
if odd body plan, at least to human observers, is a predictor or correlate of rarity. I asked
Carly about the link between countenance and ecology of giant armadillos, giant anteaters,
and maned wolves and what it might tell us about rarity. Her answers had as much to do with
the energetic balance of these mammals as with their appearance.
Maned wolf (
Chrysocyon brachyurus
) being followed by an aplomado falcon (
Falco femor-
alis
)
“Even though these creatures eat different things, they specialize on food items that just
don't support high densities of big mammals,” she responded. This, not appearance, is key.
Giant anteaters and giant armadillos are equipped to feed on ants and termites. While their
food resource is ubiquitous, it is also of low nutritional quality (with some exceptions, such
as fat-filled winged termites). The physiological and behavioral adaptations of these animals
to their food resources may account for both their looks and their rarity in nature.
Giant anteaters have low metabolic rates relative to their body size. One consequence of
their slo-mo lifestyle is that they produce only a single offspring at a time and only every oth-
er year. They occur at their highest-known densities in grasslands where their food resources
are concentrated. But even here, anteater populations are severely constrained by the wild-
fires that regularly burn through. So even where their favorite foods—ants and termites—are
