These rare whales were named for their teeth, which resemble the leaves of the ginkgo tree. Until recently they were known from only three specimens, all caught incidentally in fishing lines in the Sea of Japan in 1963. Since then others have been found stranded in different parts of the Pacific and the Indian Oceans, although many were immatures whose teeth had not erupted (they only erupt in males), making positive identification difficult.
Physical Description: The body is long and uniformly stocky, typical of beaked whales. The long beak protrudes smoothly from the melon, which is slightly indented at the blowhole. The lower jaw rises roundly along the sides where a flap of skin touches the upper jaw. Typical wishbone indentations are present on the throat.
Color: Midnight black; chest and abdominal regions are lighter, including white scars from parasites, bacteria, and, possibly fights with others of its species.
Fins and Flukes: The small, falcate dorsal fin is located well to the rear of the mid-back region. Small, thin flippers are located relatively far forward. Well-developed, well-spread flukes have a slight median notch.
Length and Weight: These whales reach a known length of 18 ft (5.5 m) and an estimated 3,200 lb (1,450 kg).
Teeth: A pair of flat, laterally compressed teeth is located behind the point at which the lower jawbones meet. No teeth are found in the upper jaw. The teeth do not erupt in females.
Feeding: Squid and pelagic fish.
Breathing and Diving: No information available.
Mating and Breeding: It has been suggested that 7 ft (2.1 m) calves are born in the spring.
Herding: Specimens were stranded individually, suggesting that these animals swim alone.
Distribution: They are known from the warm temperate and tropical North Pacific and the northern Indian Ocean. Recorded specimens are from Sri Lanka, Taiwan, Japan, and California.
Migration: No information available.
GINKGO-TOOTHED BEAKED WHALE DISTRIBUTION