The purpose of Carly’s study was to determine how wide-ranging, low-density species such as maned wolves, jaguars, and pumas navigate the countryside and to learn how they circulate among the highly altered and fragmented habitats outside reserves. She also wanted to learn whether these wild species can shift from living in natural grasslands and adapt to feeding in soy fields and cattle ranches. Finally, using maned wolves as a test case, she wanted to learn if animals that live in the Ag are more stressed, less healthy, or less reproductively active than individuals that live inside the park. New techniques that Sam and Carly were 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 mortality. 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 order 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 Jacomo, 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 relation 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 perfect 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 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.