Pinniped High levels of organic chemicals accumulate in these animals since they are near the top of food chains and have large reserves of blubber. Lactating mothers can pass the toxins on to their young. These pollutants can cause gastrointestinal cancers, decreased reproductivity and greater vulnerability to infectious diseases. Other man-made threats include habitat destruction by oil and gas exploitation, encroachment by boats, and underwater noise. Pinniped Pinnipeds, commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic marine mammals. They comprise the extant families Odobenidae (whose only living member is the walrus), Otariidae (the eared
Pinniped Nunavut, Canada. Like a modern otter, "Puijila" had a long tail, short limbs and webbed feet instead of flippers. However, its limbs and shoulders were more robust and "Puijila" likely had been a quadrupedal swimmer—retaining a form of aquatic locomotion that give rise to the major swimming types employed by modern pinnipeds. The researchers who found "Puijila" placed it in a clade with "Potamotherium" (traditionally considered a mustelid) and "Enaliarctos". Of the three, "Puijila" was the least specialized for aquatic life. The discovery of "Puijila" in a lake deposit suggests that pinniped evolution went through a freshwater transitional phase. "Enaliarctos",