Surface behavior of short-finned pilot whales
Short-finned pilot whales show a variety of movement patterns at the water surface such as traveling (...video here...), resting, socializing and foraging. During these the whales initiate a variety of behavioral units. E.g. during a behavior called spyhop, a pilot whale lifts its head and eyes above the water surface. Next to the possibility to breath, the whale gets a better surround view by elevating its eyes slightly higher above the water level than during a typical horizontal surfacing.
The combination of surface and underwater observations is important in order to explore the function of a distinctive behavior. From the surface it seems that e.g. a tailslap is a solely percussive behavior -a behavior with an acoustic signal function (...here...). From underwater an observer can get a different impression. Next to the acoustic cue, a tailslap produces a bubble cloud under water and this could also function as a temporary visual and/or acoustic curtain. Other whales are deterred from echolocating and seeing the tailslapping animal (maybe during agonistic intragroup interactions). During a further surface behavior called breaching, a pilot whale lifts most of its body above the surface and produces a noisy re-entry by hitting the surface with the lateral body surface. This could be a percussive behavior, on the other hand this might remove barnacles or cephalopod tentacles attached to its skin (...here...).
Click ...here... to see a pilot whale
duo resting at the water surface
(.mov file with 5.3 MB).