Walrus Haul-out
Odobenus rosmarus

f4 @ 1/5000s, ISO:1000, Nikon D300 w 300mm and 1.4X teleconverter

"Hauling-out," Wikipedia, the free encyclopedia. Walruses tend to occupy both terrestrial and sea ice haul-out sites, alternating between the two depending on resource availability. Walruses haul-out onto land primarily for birthing, moulting, nursing, and resting, meanwhile using sea-ice haul-out sites for foraging and predator avoidance. These physiological factors are correlated with both the duration and frequency of haul-outs among walruses. Sea ice sites are more commonly used for shorter and more frequent haul-outs compared to terrestrial sites, which are commonly used to fulfill more time-consuming requirements (i.e. breeding and birthing). Hauling-out is also used as a method of thermoregulation, therefore it is influenced by various environmental factors such as wind speed, temperature, and even time of day. Accounting for these environmental factors, walruses more frequently haul-out from late morning to early evening and avoid hauling-out during weather periods of intense cold or high winds. Haul-out frequency is at a maximum for walruses during the summer using terrestrial haul-out sites as sea ice sites are then further from foraging grounds. As female walruses haul-out for parturition, the males are territorial of the haul-out site surrounding the female herd. In these instances, hauling-out provides an opportunity for more aggressive and territorial males to mate.

Storoya, Svalbard, Norway

08/13/2010