9781422279199

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A N TA R C T I C W I L D L I F E

Marinemammals—whales,seals,walruses,andothers—breathe air like other mammals.They must surface on a regular basis to take in air before oncemore diving into their watery homes. Like all mammals, they give birth to live young and keep themnearby as the young feed from the mother. And though it doesn’t look like it from their sleek skins, whales do have a small amount of hair, usually near their mouths or eyes. Some marine mammals, such as seals or walruses, have hairy pelts, or outer skins. Top of the Chain When it’swinter in theNorthernHemisphere, it’s summer around Antarctica. That’s the season when whales are most plentiful. The waters are still near freezing, but the air temperatures are not as bitterly cold as in the winter. At the top of the Antarctic food web as the apex predators are the killer whales, or orcas. Killer whales are actually part of the dolphin family, recognizable by their single dorsal fin and torpedo-shaped bodies.Typically they aremostly blackwithwhite patches.During their time in chilly southernwaters, some species also have coatings of yellowish plankton on parts of their bodies. Killer whales stay at the top of the food chain thanks to their speed, power, and intelligence.About 16–25 feet (4.8–7.6m) long, they have huge, fierce jaws lined with sharp teeth. Their prey is just about anything moving in the sea, from fish to seals to whales.They are among the fewanimals in theworld that practice cooperative hunting. For example, one whale will rise up near a