Walrus Odobenus rosmarus Odobenidae Atlantic walrus WALR ODOROS Mammal Behavior cold snow global warming pack ice floe threatened melting melt arctic Arctic Zone North Pole polar region marine sea drift landscape icescape behavior lying resting rest symbol symbolic allegorical emblematic thoughtful thought-provoking Svalbard horizon impressing solitude lonely solitary animal loner cloudy clouds sky distance habitat sunlight coast aquatic posing huge water ocean wildlife beach big tusk flippered whiskers brown walros mammal Norway April spring Spitsbergen subarctic Rhine-Westphalia Europe pale pile pole stake animals Spitzbergen