Abstract
From the catch records and the examination of stomach contents of sperm whales caught in the Antarctic Ocean during 1953-54 season, it was indicated that sperm whales caught at night are less in number but fed better than those caught in the daytime. It seems, therefore, very probable that sperm whales in the Antarctic Ocean activily feed during the night, whereas in the daytime they are on the sea surface and do not move about so actively. However, an intensive research on the habits, particularly on the feeding habit, of sperm whales is necessary before any indisputable conclusion can be reached.
