Omura’s whale is a relatively small, super-streamlined, baleen whale. They have striking and unique asymmetrical black and white markings on the head and jaw; the lower jaw is white on the right side and black on the left.
Omura’s whale is the most recently identified whale species; they were first recognised from dead specimens in 2003 and first recognised alive in the wild in 2015. They had previously been mistaken for Bryde’s whales as both species look similar, are small, and live in tropical seas. We now know that Omura’s whale is not related to the Bryde’s whale at all.
IUCN conservation status: Data Deficient
What do Omura’s whales look like?
Omura’s whales are long, thin and super-streamlined which gives them a distinctive snake-like appearance. They are counter-shaded, dark grey above and whitish on the belly. The body is asymmetrically marked (similar to a fin whale). The lower jaw is white on the right side and dark on the left and there are four black stripes on the right side of the head only running from the area just behind the eye. Their backs are decorated with asymmetrical chevrons. Omura’s whale also has a single defined ridge on the front of the head (Bryde’s whales have three). They belong to the rorqual family of baleen whales and so have throat pleats. The dorsal fin is small and strongly hooked or curved; the flippers have white leading edges; and the tail is broad with a very straight trailing edge.
What’s life like for an Omura’s whale?
Omura’s whales usually travel alone or in pairs. Larger groups of up to half-a-dozen in a relatively small area have been seen; the whales seem to be within hearing range of each other, but give each other plenty of personal space. These aggregations are usually stable and remain in the same place for a few hours, sometimes as a result of whales feeding on the same patch of prey; at other times perhaps because a few whales engaged are in reproductive display.
Omura’s whales sing, a low, repetitive melody that they may repeat for an hour or more. Occasionally multiple whales raise their voices in an Omura’s chorus. Researchers have suggested that perhaps males are gathering around a female and fighting it out via song, or perhaps they’re wooing her with ballads.
So little is known about Omura's whales that scientists are unsure of how many exist or how rare they are. We are still learning about their distribution, population sizes, and possible variations in appearance. The species was first described in 2003 and first recognised in the wild in 2015.
What do Omura's whales eat?
Like their fellow rorqual baleen whales, Omura’s whales have throat pleats and are lunge feeders; they probably feed predominantly on schooling fish and krill which they filter from seawater. Their tropical sea habitats do not provide an abundance of food for them as prey distribution is patchy. Omura’s whales don’t seem to migrate to colder waters where food abounds.
Where do Omura's whales live?
Although they are seldom seen, Omura’s whales are still being discovered in new places and it is possible that in the coming years, further discoveries will demonstrate that they live in tropical and warm-temperate seas all over the world. So far, they have been spotted in all ocean basins with the exception of the central and eastern Pacific. Omura’s whales are seen off Madagascar all year round and do not migrate.
A baleen whale that's doesn't migrate
Most baleen whales migrate annually and swim long distances between warm water breeding areas and colder water feeding areas. Omura’s whales do not appear to make long-distance migrations; they seem to stay put and feed all year around, be it in relatively unproductive seas, and therefore do not have a limited breeding season.
Little is known about the distribution of Omura's whales. The only genetically confirmed population of living whales identified so far by researchers is found off the coast of northwestern Madagascar.
A recent discovery
We only just starting to get an insight into the life of Omura's whale. What we know so far includes:
- Omura’s whale is named after a Japanese scientist called Dr Hideo Omura.
- Omura’s whales have been heard singing at low frequencies for up to 12 hours without a pause. Choruses of singers are common with up to 5 or 6 whales singing together.
- The Omura’s whale’s asymmetrical jaw markings are unusual; only the much larger fin whale also has similar asymmetrical colouration.
- Omura’s whales were at first mistaken for little Bryde’s whales when spotted in the wild as they are a very similar size and live in the same tropical seas. Omura’s whales have also been mistaken for young fin whales in the past.
- In Madagascar, Omura’s whales are often seen along the edges of underwater banks that rise to a depth of 10m or less. Whales have been seen lunge feeding both at the surface and below the surface. Lunging sometimes involves a roll to the right side, facing down.
- Omura’s whales don’t lift their tails up out of the water when they surface.
Omura's whale need your help
The main threats...
- Habitat Loss – Living in a coastal environment means industrial development and energy exploration pose a risk to Omura's whales, along with various forms of pollution.
- Fishing gear – Omura's whales get accidentally caught in fishing nets and lines, injuring or even killing them.