Forty - two cats, including this stray one, were fitted with radio collars and tracked over two years. (livescience.com)
You've got to catch them, put radio collars on them, follow them, watch them, see what they do, see what they kill, see what they eat. (scientificamerican.com)
And we used to put a little radio collar on the bait so we knew where the tiger was sitting with the bait. (scientificamerican.com)