**7.1 Definition**

Biologging is a miniature self-recording device that attaches to an animal, records its behavior, physiological condition and nearby environmental information (Rutz and Hays, 2009). The collected data either transmits via antenna or is stored and decoded after the device is retrieved. Because it is not necessary to observe the animal directly, these devices are usually used to study animal behaviors that are difficult to track, especially those of endangered species.
