Omura whale copyA rare photo of a living Omura’s whale / Image: Salvatore Cerchio

First Field Observation of Elusive Whale Species

Omura’s whales are one of the least known and most elusive species of whale. A team of biologists have made the first ever field observations of a population just off the coast of Madagascar

In the shallow waters of coastal Madagascar, a team of biologists from the Woods Hole Oceanographic Institution have made the first field observations of one of the least understood whale species – Omura’s whales. Salvatore Cerchio, lead author of the study, says ‘this is the first definitive evidence and detailed descriptions of Omura’s whales in the wild and [it is] part of what makes this work particularly exciting.’

Until 2003, Omura’s were thought to be a pygmy type of the Bryde’s whale owing to their similar dorsal fins and tropical range. However, genetic data from stranded carcasses classed them as their own species. They are understood to be smaller than Bryde’s whales and to have unique markings: a dark jaw on the right and a lighter jaw on the left. ‘They appear to occur in remote regions and are difficult to find at sea because they are small,’ says Cerchio. ‘They range in length from approximately 33 to 38 feet – and do not put up a prominent blow.’

Initially, Cerchio and his team were surprised to see the Omura’s whale. The first, spotted in the Nosy Be region in 2011, was originally misidentified as a Bryde’s whale too, mainly because, according to Cerchio ‘from the little information there was on their habitat and range, Omura’s whales were not supposed to be in that part of the Indian Ocean.’

mapOmura’s whales were studied in the Ankivonjy Marine Protected Area, Madagascar / Credit: Figure 4 from Cerchio et al. 2015 Royal Society Open Science CC-BY 4.0

The sightings increased when they moved to a different site in 2013, where the team has now catalogued approximately 25 individuals through photo identification. They have observed the Omura’s lunge feeding, possibly for zooplankton, as well as the behaviour of four mothers with young offspring. ‘The presence of mothers with young calves suggests that our study site probably represents breeding habitat where females give birth,’ say the authors.

Recordings of their vocalisations were also made, which the study says are often choruses between multiple individuals. For now, the team predict that the Omura’s whale song is a male-limited trait, however, Cerchio will carry out further study on the behaviours and vocalisations in the field. He hopes to produce the first estimate of abundance for any population of the rare species.

With the first detailed description of their appearance and behaviours, the team hopes that it will be easier to distinguish Omura’s from Bryde’s whales in the future.



Love diving? You'll love these. Sign up today to immediately download our unique FREE gifts -

AROUND THE WORLD IN 80 WRECKS - DIVE's 70-page, beautifully illustrated, colour guide to the world’s best wrecks

SCUBA STORIES - DIVE's collection f real life stories where divers, who have got themselves into perilous situations, describe how they reacted and what actions they took to ensure they lived to tell the tale

PACIFICHighlights of the Pacific - Dancing mantas in Hawaii • The Best Diving in the World, Galápagos, Cocos, Malpelo & Socorro • Mass Spawning Events in Palau

New Upright Gift Banners 300 x 600 px

Sidebar SUBSCRIBE spring 21 large2

Destinations Spotlight

Need inspiration for your next dive trip? Try one of our featured destinations from DIVE's travel partners.

sidebar philippines sidebar bahamas sidebar mexico sidebar fiji sidebar st helena 2020 Sidebar Egypt sidebar banner sabah sidebar banner belize sidebar banner south africa

DIVE Partners

sidebar banner egypt new ceningan divers ad 300x100 LH 300 min giphy subex Wakatobi Siladen Aggressor Fisheye Dive Worldwide gozo banner Arenui

Read DIVE magazine

DIVE magazine is available to read on many devices. Simply click one one of the options below

PCMac final
Apple finalAndroid final

Like what you see?

Join us on social and keep updated daily...