iOS 7 Programming Fundamentals

Colophon

The animal on the cover of iOS 7 Programming Fundamentals is a harp seal (Pagophilus groenlandicus), a Latin name that translates to “ice-lover from Greenland.” These animals are native to the northern Atlantic and Arctic Oceans, and spend most of their time in the water, only going onto ice packs to give birth and molt. As earless (“true”) seals, their streamlined bodies and energy-efficient swimming style make them well-equipped for aquatic life. While eared seal species like sea lions are powerful swimmers, they are considered semiaquatic because they mate and rest on land.

The harp seal has silvery-gray fur, with a large black marking on their back that resembles a harp or wishbone. They grow to be 5–6 feet long, and weigh 300–400 pounds as adults. Due to their cold habitat, they have a thick coat of blubber for insulation. A harp seal’s diet is very varied, including several species of fish and crustaceans. They can remain underwater for an average of 16 minutes to hunt for food, and are able to dive several hundred feet.

Harp seal pups are born without any protective fat, but are kept warm by their white coat, which absorbs heat from the sun. They are nursed for approximately 12 days, after which they are abandoned (though they will triple their weight in this time due to their mother’s high-fat milk) . In the subsequent weeks until they are able to swim off the ice, the pups are very vulnerable to predators and will lose nearly half of their weight. Those that survive ...