Our Jaguar
I teach a course with a colleague every winter break called “Tropical Agriculture, Ecosystems, and Conservation”. This course takes students to the wonderful country of Belize in Central America. We are based at the BFREE site (for Belize Foundation for Research and Environmental Education) near the Bladen Nature Reserve in Southern Belize. In addition to lectures, field outings, and hands-on demonstrations, the students all participate in research projects. I discuss one of those projects–our traps for dung beetles–in the science diaries.
Another student project involved using camera traps to determine what kind of animal activity was in certain locations around the reserve. These cameras use motion and heat detectors to trigger the shutter. You set them up in a likely spot, set the trigger, wait for a day or so, and Voila! photos of animals you would not normally be able to see. Except, it was not quite that easy. Our biggest problem with these digital cameras was figuring out the instructions, which had to have been written by folks from Mars. That took four people about four solid hours of aggravation. Also, because there was no way to download the pictures (the camera trap had no screen), we had to wait until we were back in the states to see what was in the pictures. We had several hundred shots of nothing but “blanks” – that is, camera shots with no animal pictured, often triggered by insects or rain. Then, to our surprise, there was the shot of our male jaguar! A cat clearly on a mission! Camera traps, so called because you “catch” an image of the animal, are used for mammal surveys, especially with animals that can be individually identified from markings, like our jaguar. Once set up, they can be used to count the number of “recaptures” (those animals that appear more than once in photos), and the population size can be estimated from a ratio of the number of “recaptures” to “total captures”.
The other animal that we “captured” on camera was a low flying bat! The camera was only about three feet off the ground, and most cameras take several seconds to trigger the shutter once the infrared beam is broken. Our camera, on the other hand, triggers almost immediately, so even a fast flying object can be captured. It was still a very lucky shot!
For more about jaguars, visit: http://savethejaguar.com/jag-index
For more about bats: http://www.batcon.org/home/default.asp
October 31st, 2007 at 4:54 pm
Are dung beetles “poo specific”? Any ideas how they came to select the monkeys you are studying for their foraging?
February 28th, 2008 at 2:57 am
In answer to Linda: some of them certainly are. There is one species in Florida that lives on gopher tortoise dung in the tortoises’ deep burrows. On the flip side, there are species that will eat almost any dung, plus carrion, plus rotten fruit and maybe fungi. In between, there are species with a range of likes and dislikes. Most of the species of dung beetles in the Amazon are generalists; however, there are a few extreme specialists (one lives in the fur of sloths and waits for the sloth’s once a week trip to the ground to defecate!). It seems that the beetles we collect (somewhere around 50 species) are attracted to primate dung, human dung, and also pig dung. It makes a certain amount of sense that the dung of these species is the most attractive to dung beetles as the biomass of monkeys and peccaries is higher than most other mammals in this part of the Amazon. So, more to eat!