I haven't been to Paraguay, but FAUNA Paraguay (below) will provide information on the country's mammals as well as eco-tours (the website linked below has quite a lot of information on some of Paraguay's excellent mammals, which include Jaguar, Puma and several Armadillo species....) as well as trip reports and so on.
Other People's trip reports FAUNA Paraguay - " Dedicated to the study of the Paraguayan fauna, this site counts on a huge image gallery of photos and videos, as well as supporting local conservation projects. Expert-led eco-tours to the Chaco (a paradise for mammals) and Atlantic forest also on offer."
