Jaguars eat just about anything. A study conducted nearby to Caiman Ecological Refuge in 2003-2004 compiled a list of items found in jaguar feces. This particular study included prey items from 19 taxa. This varied diet adds to the adaptability of this cat. The Leopards in Africa are considered to have the broadest diets of any cat with a prey list of close to 100. The current list of species eaten by Jaguar sits not far behind at 85!
Jaguars do however show a preference for large mammalian prey. Much of the Pantanal is used for cattle ranching, and thus cattle make up a large component of a Jaguars diet. Cattle Ranching has been practiced here for about 200 years and so one can truly say that the presence of cattle is entrenched in the day-to-day life of a Jaguar. The cow is as much a part of this landscape as the Acacia tree is to an African savanna.
Prey larger then 15 kg makes up about 60% of a Jaguars diet. In the study the most common ‘wild’ or ‘native’ species killed was capybara (31%) followed by Caiman (20%). Another species, which constitutes a large percentage of a Jaguars diet, is the Marsh Deer with 11%. Livestock represented 28% of kills found.
The study also set out to prove if the presence of the cattle was having an impact on Jaguar population levels. They found that even though the abundance of livestock, on that particular ranch, was 18 times higher than wild prey in the area, livestock represented 28% of the kills, resulting in less than 20% of the biomass consumed. This consumption rate was much less pronounced then one might assume in an area so rich in cattle. The results provided some evidence to support the fact that the wild prey base is indeed sufficient to sustain the population of jaguars and that the Jaguars do not require a subsidy of livestock to survive.
It stands to reason that the chances of finding the carcass of a cow are higher than that of a capybara. Also, cowboys managing their herds, find a lot of the Jaguar kills for us. Again, it makes sense that the cowboys are more vigilant to finding and reporting cattle deaths than of other wild/native species.
So whilst a lot of the Jaguar kills that we manage to find at Caiman Ecological Refuge are of cattle, we need to realize that this is only a fraction of what they are really killing.
Written by Adam Bannister
Inspired by the research of:
Cascelli de Azevedo, F. C. and Murray, D. L. (2007). Spatial organization and food habits of jaguars (Panthera onca) in a floodplain forest. Biol. Conserv. 137: 391-402.