Significant differences separate Antarctic animals and Arctic animals because of vast differences between the Arctic and Antarctic. From photographs, the locations seem similar--eternally frozen wastelands. The main difference is that the Antarctic is a continent, and the Arctic is not. The Antarctic is a land mass with mountains. The Arctic is an empty ocean that often has ice floating on it. The Antarctic is the coldest place on Earth.
The Antarctic has several species of whales and a few species of seals, but Antarctic land animals can be summed up in one word: penguins. This species of seabird spends half its life on land and half in the water. It hunts and eats--fish, krill and squid--in the water and breeds on land. Only a minority of the penguins species live in Antarctica, but they do only live in the southern hemispheres. Some of them, like the Galapagos penguins live near the equator, although this is largely because the Galapagos Islands are cooled by the Humboldt current. The majority of penguins live in Australia, New Zealand, South America, South Africa and the islands of the southern hemisphere.
Arctic Predatory Mammals
The top predatory mammal of the far north is the polar bear. They feed almost exclusively on seals. They wait patiently for the seals to come up for air. Polar bears also eat carrion of whales, walrus and seabirds. They also have even been observed eating vegetable matter like kelp. Like other bears, polar bears will eat anything but usually seals are the only prey they can catch. The other Arctic predatory mammal is the Arctic fox, which lives further south and feeds mostly on small mammals. Unlike Antarctica, the Arctic circle is not over water. It is over land where some vegetation--mostly tundra moss--grows. This difference affects the fauna in the Arctic.
Arctic Herbivorous Quadrupeds
The existence of tundra around the Arctic makes possible herds of caribou and reindeer. Most of the Antarctic Circle is over water, hence no tundra, no vegetation and no herds of large herbivorous quadrupeds exist. These Arctic herds are nomadic. They eat lichens and moss that grows on tundra. These herds are relatively safe from predators in this latitude as the Arctic fox is too small and the polar bear too slow to pose serious threats.
Arctic Sea Mammals
Arctic sea mammals feed on the abundant sea life in the northern polar region. This abundance is nonexistent in the Antarctic, so no large indigenous aquatic mammals live in Antarctica. Arctic sea mammals include seals, walruses and a variety of whales large and small. One of the strangest of these whales is the narwhal. It is a small-toothed whale that lives in the Arctic year-round. It feeds on bottom-dwelling fish deep under the ice. Its primary characteristic is a long, straight helical tusk that is almost the length of the rest of its body, extending from its upper jaw. The narwhal uses this tusk to uncover its bottom-feeding prey.