For tracking devices, the genre falls into LBS, or Location-Based-Services. LBS devices generally have some type of transceiver (I've developed many; from GPS to WAN-cellular, to RFID and even ZigBee protocols), and then the big kicker: a significant battery for the transceiver. All this adds up to a relatively larger volume than what is depicted in this device shown, which I liken more to a collection of sensory collectors.
It doesn't look like it. I've use the 'Loc8tor' for keeping track of my cats and dogs. It provides directional (arrows) as well as distance (sound) information up to about 600'. The same company has other products that work from further distances, but not as precise.
@pete.cross: That's a very interesting master's thesis ("Control, communication and monitoring of intravaginal drug delivery in dairy cows"). I'd imagine that getting a cat to wear a collar is very simple in comparison.
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