Jaguars can also provide ranchers with an additional source of income. For example, several ranches in the Pantanal, San Francisco among them, run ecotourism operations that have turned a liability into a valuable asset.
Conservationists say that the next decade will be pivotal for jaguars, in the Pantanal and throughout its range, which runs from northern Argentina to the borderlands shared by Mexico and the US.
No one knows the precise rate at which the number of jaguars is declining or just how many jaguars there are. But the World Conservation Union pegs the total free-ranging population at fewer than 50,000 adults and classifies the animal as near threatened.
Jaguars may not yet be in such desperate shape as Asian tigers, whose noncaptive breeding population has plummeted below 2,500, or African lions, of which there are perhaps only 20,000 to 30,000 left in the wild. But if conflicts with people and their livestock are not soon resolved, conservationists warn, jaguars could quickly trace a similar trajectory.
At first pass, the conflict between jaguars and ranchers would seem to be intractable. "The cats are where the cows are, and the cows belong to people," said Almira Hoogesteijn, a research veterinarian at the Center for Research and Advanced Studies of the National Polytechnic Institute in Mexico.
But even though jaguars kill and eat cattle, they do so less often than one might imagine.
A quantitative picture of the dietary habits of jaguars emerged from a study conducted by Azevedo at San Francisco in 2003 and 2004.
Over the course of nearly two years, Azevedo and his field assistants collared 11 adult jaguars and tracked their movements. They also methodically collected their scats and examined the carcasses of their prey.
The contents of the scats revealed that the giant rodents known as capybaras were the jaguars' most common prey, followed by caimans and marsh deer. Of 113 carcasses confirmed as jaguar kills, capybaras made up 35; caimans, 23; and cattle, 32.
Azevedo, a postdoctoral fellow at the University of Sao Paulo, then measured the cattle that were killed against a larger background.
In all, 169 cattle deaths occurred at San Francisco during the study period, he and his former thesis adviser, Dennis Murray of Trent University in Canada, reported in the September issue of The Journal of Wildlife Management. Nineteen percent were lost to jaguars. Out of a 5,000-head cattle herd, the jaguar's take faded even more in significance: It amounted to less than 1 percent.
Jaguars in the Pantanal seem to be on a teeter-totter that could tilt strongly in one direction or the other. Given the stakes, Sandra Cavalcanti, a jaguar expert who will soon receive her PhD from Utah State University, said researchers no longer have the luxury to just study these elegantly patterned beasts. To save them, she said, "we have to act."
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