 In the case of reptiles such as crocodiles and turtles, gluing the unit onto the animal's skin or carapace using epoxy (or similar material) is the most common method and minimises discomfort.In deployments on marine mammals such as phocids or otariids, the device would be glued to the fur and fall off during the annual moult.Units used with turtles or marine animals have to resist the corrosive effects of sea water and be waterproof to pressures of up to 200bar.