ANCHORAGE, Alaska -- Two conservation groups sued thefederal government Tuesday claiming marine mammalregulators are not doing enough to protect polar bearsand walruses against the combined threat of oil andgas exploration and global warming. The groups say the U.S. Fish and Wildlife Service didnot fully consider the effects of global warming, suchas diminished sea ice, as it wrote regulationsallowing for incidental harassment of polar bears andwalruses by the industry in the Beaufort Sea andnearby coastal areas. Polar bears depend on sea ice for their main prey,ringed seals and bearded seals. Beaufort Sea femalesuse coastal land or sea ice for digging snow caves togive birth. Female walruses follow the receding ice edge north inspring and summer, using the ice as a platform to diveto the bottom and feed while calves remain on the ice.Polar bears can suffer harm from drilling, seismicwork and transportation, said Earthjustice attorneyClayton Jernigan, who filed the lawsuit on behalf ofthe Center for Biological Diversity and PacificEnvironment, both based in California. The petroleumactivities disturb feeding, cause abandonment ofmaternity dens and disrupt polar bear life cycles,Jernigan said.