Indopacetus pacificus
Longman's beaked whale

Specimens are recorded from Australia, Somalia, South Africa, the Maldives, Kenya, and Japan. From this information, the full range is currently thought to be the Eastern Pacific through the Indian Ocean to the eastern coast of Africa. Specimens have appeared rarely but widely throughout the Western Pacific and Indian Oceans. Until 2002, this species was only known by two skull specimens, recovered in 1926 and 1968. Flesh samples and live sightings have only been documented very recently. ()

Longman’s beaked whales are pelagic and feed in the deep sea. This conclusion is based on the extreme rarity of sightings and the lifestyles of related species. Also, a specimen was discovered off the coast of Japan in July of 2002. This specimen had distinctive bites from a cookie cutter shark (Isistius brasiliensis). This shark generally lives in the deep sea and its bites are common in deep sea marine life. There is very little data for any of the species in the family Ziphiidae, but one study found that the maximum depth for this related species was 1267 meters. ()

Size estimates range from 4 to 9 meters based on extrapolation from skull measurements. A Japanese specimen was 6.5 meters in length, which seems about average based on partial skeletal specimens. Like all beaked whales, this species has a prominent slender beak. Also diagnostic of beaked whales, the throat has two grooves which form a V shape and the fluke is not notched. This whale has a proportionately smaller head than most beaked whales. It is, however, larger overall than most of its close relatives. Longman’s beaked whales are most morphologically similar to Baird’s beaked whales (Beradius bairdii). They may be distinguished, however, because Longman’s beaked whales have a blow hole with concavity oriented forward, toward the anterior of the whale. In Baird’s whales the blow hole tilts toward the posterior. The dorsal fin is larger than that of most beaked whales. The lower jaw contains only a pair of oval teeth, which do not protrude from the jaw. The skin coloration varies between brown and bluish gray and tends to lighten around the flank and head. These whales are sexually dimorphic, with males tending to be larger. Weight estimates could not be found. ()

Natural lifespan of this species is unknown; it has never been kept in captivity.

Individuals have been sighted in the Pacific in groups of up to 100 or singly. Groups of greater than ten have been most commonly recorded. ()

Home Range

Home range size is unknown.

Pelagic beaked whales use echolocation to locate food. ()

The Japanese specimen’s stomach contents were analyzed, and revealed the beaks of cephalopods. ()

Based on the distinctive bites visible on the Japanese specimen, cookie cutter sharks (Isistius brasiliensis) may feed on Longman’s beaked whales. Their large size makes them unlikely prey. ()

The stomach contents of a Japanese specimen revealed parasitic nematodes. Specifically, Anisakis individuals were extracted. These roundworms are known to parasitize cetaceans. ()

It is unlikely that beaked whales have negative impacts on humans.

Longman's beaked whales are important members of healthy ocean ecosystems.

There is very little information on Longman's beaked whales, they are considered data deficient by the IUCN and are not listed by CITES or the U.S. Endangered Species Act.