L. obliquidens Skull Replica measures 15.3 inches. Known as Pacific White-Sided Dolphin. L. obliquidens Skull is museum quality polyurethane cast. Made in USA. Cast of an original California Academy of Sciences specimen. 2-part skull (separate cranium and jaw).
L. obliquidens is from the coasts of the north Pacific and adjoining waters.
The L. obliquidens has three colors. The chin, throat and belly are creamy white. The beak, flippers, back, and dorsal fin are a dark gray. Light gray patches are seen on the sides and a further light gray stripe runs from above the eye to below the dorsal fin, where it thickens along the tail stock. A dark gray ring surrounds the eyes.
L. obliquidens is extremely active and mixes with many of the other North Pacific cetacean species. It readily approaches boats and bow rides. Large groups are common, averaging 90 individuals, with super groups of more than 300.
L. obliquidens prey includes mainly hake, anchovies, squid, herring, salmon, and cod. They have an average of 60 teeth.
The range of the Hookfin Porpoise arcs across the cool to temperate waters of the North Pacific. Sightings go no further south than the South China Sea on the western side and the Baja California Peninsula on the eastern.
Populations may also be found in the Sea of Japan and the Sea of Okhotsk. In the northern part of the range, some individuals may be found in the Bering Sea.
The L. obliquidens appear to follow some sort of migratory pattern, on the eastern side they are most abundant in the Southern California Bight in winter, but further north (Oregon, Washington) in summer.
Their preference for off-shore deep waters appears to be year round. The only known predators of the Hookfin Porpoise is the Killer Whale and humans.
The total population may be as many as 1 million. However, the tendency of Pacific white-sided dolphins to approach boats complicates precise estimates via sampling.
These dolphins keep close company. L. obliquidens swim in groups of 10 to 100, and can often be seen bow-riding and doing somersaults. Members form a close-knit group and will often care for a sick or injured dolphin.
Animals that live in such large social groups develop ways to keep in touch, with each dolphin identifying itself by a unique name-whistle. Young dolphins communicate with a touch of a flipper as they swim beside adults.
L. obliquidens can dive underwater for more than 6 minutes to feed. They have small conical teeth that help them catch and hold on to their prey; each tooth row contains 23 to 36 pairs of teeth.
Instead of using their teeth to chew their food, dolphins use their teeth to grip food before swallowing it whole head first so the spines of the fish do not catch in their throats.
L. obliquidens often work together as a group to herd schools of fish. Each adult eats about 20 pounds of food a day.
Pacific white-sided dolphins in the United States are not endangered or threatened, but they are protected under the Marine Mammal Protection Act. A primary threat to Pacific white-sided dolphins is entanglement in fishing gear, such as gillnets and trawls.