Whale watch

Like the whales in the Antarctic ["Good Whale Hunting," by Robert L. Pitman, 12/03-1/04], orcas in the Pacific Northwest also seem to occur as distinct populations: "resident" and "transient." The former subsists on fish, primarily salmon, whereas the latter preys primarily on seals. Could these two be different species as well?

Ken Sweetman

Bend, Oregon

ROBERT L. PITMAN REPLIES: Whale scientists differ on how many species of killer whale inhabit the Pacific Northwest. The evidence is clear from genetic studies and years of systematic field observations that residents and transients do not interbreed, and haven't for a very long time, even though they often occur in the same areas. Many would thus infer that reproductive barriers are already in place, and that the two forms are best regarded as separate species. How the populations are described matters because it can influence the level of protection the animals get under the law.

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