Now, 20 years later, the area still has not fully recovered. At the time of the spill, two groups of orcas, or killer whales, were swimming in the area. One of these groups of whales appears to be headed for extinction, and the other is recovering more slowly than scientists had predicted.
The first group, called AT-1, wasn’t large to begin with: When the spill happened, the group had 22 whales. Nine of these whales died during the spill, and since then, no baby whales have been born in the group. The older males — who can live to be 60 — have been dying off. Now, only seven whales remain.
These orcas may look like and live in the same areas as other killer whales, but orcas in the AT-1 group are genetically different and communicate with a different set of sounds. They are transient orcas, which have larger home ranges than the other kind of killer whales, called resident orcas. Transient orcas eat mammals, such as harbor seals, sea lions, porpoises and other whales; resident orcas eat fish. These two types of killer whales don’t breed with each other.
20分..爽手
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更新1:
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