Biology Reference
In-Depth Information
developing back at the lab allowed them to measure health from hormones extracted from
the dung. If Carly and Mason could find enough scats of this grassland wolf, this charismatic
species might be the most revealing one to study.
Biologists use the terms “source” and “sink” to define the dynamic at work here in the
Cerrado. Source sites are places where recruitment, or population increase, exceeds mortal-
ity. The expectation is that maned wolves have greater breeding success inside Emas than
in Ag land, but because the park is too small to hold all the individuals born in the reserve,
breeding individuals must spill out into the surrounding landscape. Sinks present the opposite
situation, in which maned wolves (or members of another species) emigrate from the source
to a location where they die in higher numbers than are recruited into the local population.
With not enough large, preferably linked sources, and too many sinks, the species eventually
will die off.
Some biologists avoid following their species into farmland or altered habitats. But in or-
der to answer her questions, Carly randomly selected sampling routes that wound through the
park as well as an additional 4,000 square kilometers of soybean fields, cattle ranches, and
forest fragments on adjacent private lands. Curious about this woman and her dog, the local
ranchers agreed to allow her to roam freely.
Within weeks after arriving in Emas, Mason had made the Cerrado his home, adapting
well from a stint in the bitter cold of the Canadian Rockies, where he had worked on wolf,
caribou, and moose scats. Now he was in the dry oven of the Cerrado and was mastering
Cerrado mammal spoor: puma, jaguar, giant anteater, giant armadillo, and maned wolf. To
train Mason on tropical mammals, Carly had obtained sample scats from zoos in the United
States and from Leandro Silveira, the dean of Brazilian carnivore biologists, and his biologist
spouse, Anah Tereza de Almeida Jácomo, whose home base was Emas.
When Carly told her friends about her project, they all expressed admiration for the maned
wolf. The maned wolf, though, it should be said, is not actually a wolf at all, bearing no rela-
tion to the gray wolf. The vivid red fur, trimmed in black and white, and the lovely mane of
this Cerrado carnivore make it one of the most striking of mammals. The showstopper is to
watch a maned wolf 's aristocratic gait—a smooth trot on its strikingly long legs that matches
the elegance of its coat. Nothing else on nature's runway compares to this handsome wild
canid.
If the maned wolf is not a wolf, and the giant anteater an evolutionary oddity, no mammal
is as strange as a giant armadillo. Its armorlike plating and bullet-train shape make it the per-
fect inspiration for a futuristic subterranean vehicle. Its huge claws, designed for digging its
way through the underworld, are also impressive. Few biologists had ever studied this species
before, and those who did mostly focused on its burrowing behavior and diet. Few had even
found one alive, with or without the help of scent dogs. George Powell, our jaguar tracker
from Peru (chapter 3), told me that once his research staff had heard loud snoring sounds
