Longman's beaked whale
In 1996, Longman's beaked whale was placed in the Mesoplodon genus however further studies and discoveries have seen it recently placed in its own Indopacetus genus. Up until only a few years ago, this whale could have taken the title of 'least known whale' with all available information coming from only two skulls. It is now apparent, however, that individuals of this species were mistakenly identified as belonging to the Hyperoodon genus.
The Longman's beaked whale has a distinct beak, with a large lower jaw which sticks out beyond the upper jaw. There are also two small oval-shaped teeth at the tip of the jaw, thought to erupt only in males. It has a relatively large, falcate dorsal fin which is set well back on the body. The melon is well developed and bulbous, and there is usually a distinctive crease between melon and beak which is paler than the rest of the body, that can range from dull brown to tan or greyish brown. This colouration may become lighter with age. The belly is lighter, and there may be a lighter patch visible behind the eye. The dark colour on the dorsal side extends in a band towards the flippers, while the lighter colour of the belly extends up the shoulder. These unusual markings may aid in identification at sea. The body may be marked with oval white or yellow marks, which may be scars resulting from cookie cutter shark bites. Males often exhibit linear scars thought to be from other male Longman's beaked whales during male-male competition.
Longman's beaked whales have only recently been positively identified at sea, but in some of those sightings they have been seen associating with other species including pilot whales, bottlenose and spinner dolphins. They have been seen in pods of between 10 and 100 individuals and are noted as being dramatic in their swimming behaviour, breaching and porpoising at high speed. This may suggest they are somewhat more gregarious than many other beaked whale species and it has been reported that they sometimes show an interest in boats.
Strandings and occasional sightings suggest that Longman's beaked whales inhabit a vast area covering tropical to sub-tropical waters in both the Indian and Pacific oceans. It is believed that similar to other beaked whale species, they are threatened by noise pollution, marine debris, and climate change. A worldwide population estimate for this species is not available and Longman's beaked whales are listed by IUCN as Data Deficient.