Instrument: Wildlife Computers TDR
Time depth recorders (TDR's) manufactured by Wildlife Computers, Redmond WA) are designed for studies of seals, penguins, fish, and marine mammals. Standard TDR's are mounted externally on the animal's body, where they record temperature and depth. See more information from the manufacturer.
A combined satellite-linked time-depth recorder (TDR) and Fastloc GPS receiver (Wildlife Computers, model MK10AF) was epoxied to each animal's pelage on the dorsal midline.