It is not known for certain how long a whale may live after completing its growth. At the present time, commercially important species seldom attain physical maturity before being captured. Many whales which are captured are measured for scientific study. Such measurements also keep the whalers from taking undersized juveniles. Whales apparently do not live to be very old. Fifty years appears to be the best current estimate of a life span.
Back of a gray whale showing barnacles and barnacle scars. Courtesy of Scripps Institute of Oceanography.
Whale Intelligence
Whales are apparently very intelligent animals. Whalers have remarked how difficult it is to approach whales which have previously escaped. The gray whales were observed actually avoiding the coast after shore whaling had been carried out for a few seasons. Animal trainers have found the toothed whales particularly apt pupils, and these animals are the stellar attraction of the various oceanaria.
Whale Senses
Sight
Little is known, however, about the capabilities of the various sensory organs. Certainly the eyes are very important and are effective under water. It is not likely that the eye is very effective out of water, even though whales do elevate the head out of the water for a look around. The behavior has been appropriately called “spyhopping,” and it is manifested usually in the ice floes. Killer whales are believed to search the sea’s surface and the edge of the icebergs for seals and birds.
Hearing
Whales appear to have very acute hearing. The report of a whaling gun will alarm whales which have previously tolerated the whaling vessel close aboard. Whalers have noted that in very foggy weather whales are much more difficult to approach because of the increased sensitivity to noise. The toothed cetaceans which are gregarious are capable of a great variety of vocalizations. Much of this is ultrasonic to man and it has been suggested that these emissions are used like man’s sonar for finding obstacles and food. Considering the limited range of vision possible in water which is usually hazy or turbid, such a feature would be most useful. There is a continual chatter among members of a porpoise school, or gam, as the whalers call them. The accumulated noise serves as a beacon to which straying members can home when they have gotten out of visual range, which incidentally is under 300 feet. No one yet knows exactly how these animals can produce these sounds without being able to move air across the vocal chords. They do not exhale under water, and yet they are continually noisy.