Federal scientists in Alaska waters have sighted a rare mammal, the endangered blue whale, shown, Thursday, July 15, 2004, approximately 100-150 nautical miles southeast of Prince William Sound. The blue whale is the largest animal known to live on Earth. The sighting by researchers on board a National Oceanic and Atmospheric Administration vessel means the blue whale population may be getting healthier and expanding back to traditional territories. (AP Photo/National Oceanic and Atmospheric Administration)