National Geographic : 1984 Dec
Six lolling sperm whales (above) chat in their mysterious clicking language. Codas-unique patternsof clicks-may permitindividuals to identify each other. Other clicks may act as sonar to locate and, some believe, to stun prey. Aboard the researchvessel Tulip, the author (below) tracks sperm whales in the northernIndian Ocean. 776 Sri Lanka has won worldwide gratitude and congratulations for its role in establishing the Indian Ocean as an international marine mammals sanctuary.Leaders in that effort have been Sri Lanka's National Aquatic Resources Agency andits affiliatedCentrefor Research on Marine Mammals of the IndianOcean.