Biology Reference
In-Depth Information
highly concentrated, giant anteater populations are often knocked back by killer fires racing
across the pampas.
Maned wolves, which are restricted to the grasslands of central South America, also occur
at naturally low densities, half of our two-part condition of rarity. The maned wolf is the
largest canid that does not hunt prey larger than itself. Its body mass may well be the limit
at which a canid is able to survive on small prey—primarily rodents, birds, and armadillos,
heavily supplemented with fruit. To meet their dietary demands, maned wolves traditionally
forage across large home ranges of about 70 square kilometers, thus contributing to their nat-
ural rarity.
These unique adaptations—the elongated, toothless skull of the giant anteater that accom-
modates its extra-long ant-lapping tongue; the large claws of the burrowing giant armadillo,
used for ripping open termite mounds; the fox-on-stilts appearance of the maned wolf—can
be viewed in a new light. These striking features are all the evolutionary products of highly
specialized feeding behaviors. Might they be unfavorable attributes in a changing world? An
intense specialization on a highly patchy food source, such as termite mounds, works only
if the species in question—in this case an anteater—can move effectively between patches.
Thus, if the species is to thrive here in the Cerrado, surrounding ranchers would need to keep
the termite mounds in their cattle pastures and anteaters would need corridors to reach these
patches of rich termite concentrations. The long legs of the maned wolf might allow it to
travel long distances easily and pounce effectively on its abundant prey. Being a medium-
sized predator but basically subsisting on abundant small mammals such as rats means that
you could find your principal food source in any open habitat. Natural selection may have no
foresight, but it seems to have left the maned wolf a better chance of survival than the other
members of the Cerrado trio.
Before heading out in the morning, Carly checked her data sheets and GPS unit and
strapped on her snake guards. She counted the bottles of drinking water on hand for us and
Mason, and we set out. When we reached her starting point on the transect, Carly released
Mason with the command “Let's go to work!” Nose and tail in the air—the posture of a
skilled scent dog—Mason trotted off into the grass.
The scent dog weaved back and forth across the route, off leash but always within sight of
Carly. Within minutes, he came running back to fetch us. Then he raced back into a grassy
area under some trees and sat down with his nose pointing a few inches away from a pile
of maned wolf dung. Despite being an excellent fieldworker, Carly admitted she would have
walked right past this scat had she been on her own. She immediately praised the dog and set
about collecting the scat and noting its location on her GPS unit. The Cerrado project marked
only the second time scent dogs had been called to duty outside the United States and Canada
and the first under the tropical sun. By the end of a six-week pilot study here in 2004, three
dog-handler teams had collected more than 650 scat samples from pumas, jaguars, and maned
