The FZS (Frankfurt Zoological Society) have been running some successful projects in the Jambi region of Sumatra. One of those being the tracking of wild elephants through the use of radio collars. By attaching a radio collar to one elephant in a herd the FZS team can effectively track the entre herd and can act quickly in the event the herd might get too close to a village. This helps prevent human/elephant conflict and further deaths of the critically endangered Sumatran elephant.
Full article on Elephants of Sumatra http://elephantsofsumatra.com/radio-collar-tracking/