Summarize the points made the lecture. Then, be sure to explain how they respond to the specific arguments presented in the reading passage.
Narrator: Now, listen to part of a lecture on the topic you just read about.
Professor: Despite what the reading says, it’s perfectly possible that the white orca called iceberg by Russian scientists is in fact the same individual that was spotted earlier near Alaska. For one thing, the exact color of an orca’s skin can change a bit from season to season. The reason for this is algae. Algae are small plant organisms that grow on whale skin during some parts of the year. Algae growth would make white skin look a bit darker. The Alaskan sighting occurred during a different season than the Russian sighting, so if we take into account the seasonal variation in algae growth, it could have been the same whale seen both times, only one time it was covered with more algae than the other time.
Second, about the distant problem. It’s important to know that orcas live in groups that have different lifestyles. Some groups hunt mammals, while other groups hunt fish. The mammal-eating orcas tend to stay near coastlines and not migrate far, just like the reading say. However, scientists have determined that iceberg belongs to a fish hunting group. Fish-hunting orcas follow migrating fish and can travel over 2,000 kilometers in the open ocean. So it wouldn’t have been unusual for iceberg to travel between Alaska and Russia.
Third, age estimates based on the size of the dorsal fin are not necessarily accurate. You see, after an orca reaches twenty years of age, its dorsal fin doesn’t grow anymore so when scientists see an orca with a fully grown dorsal fin, that orca could be twenty years old, but it could also be twenty-five or thirty years old. So, iceberg could easily have been older than the scientists estimated, which means it could have been the same orca as the one seen in Alaska earlier.