Gray Whale Calf Killed by Orcas
Antarctic minke whale image by: docentjoyce
Estero Bay, Morro Strand State Beach, Morro Bay, Calif.
Western Gulls feeding on carcass.
Killer whales are dolphins, which are toothed whales. All killer whales have teeth on both their top and bottom jaws – 48-52 teeth in total. These teeth can be up to 4 inches long. Although toothed whales have teeth, they don’t chew their food – they use their teeth for capturing and tearing food. Young killers whales get their first teeth at 2-4 months of age. Orcas may work in pods to hunt their prey.
Killer whales are ravenous feeders, eating up to 136 kg (300 lbs) of food a day. They feed on fish (including sharks and rays), squid, and marine birds, as well as more than 35 different species of marine mammals, including sea otters, seals, sperm whales, minke whales, humpback whales, gray whales, and blue whales. A killer whale’s diet varies depending on its location. In the Antarctic, for instance, the animal’s diet consists of about 67 percent fish, 27 percent marine mammals, and 6 percent squid. In the Bering Sea near Alaska, the diet is about 65 percent fish, 20 percent squid, and 15 percent marine mammals. Scientists have observed that resident and transient killer whales in the same area have a different diet. In the Pacific Northwest of the United States and Canada, for example, resident populations feed mainly on salmon and other near-shore fishes, while transient populations feed primarily on harbor seals and porpoises.
Killer whales often hunt in packs, working together to encircle and herd prey into a small area before attacking. While hunting, killer whales rely on echolocation to gather information about their surroundings. A killer whale emits high-frequency clicks that bounce off objects. The animal analyzes the reflected sound waves to locate prey and avoid obstacles.