It is strange to think that a large mammal such as a whale can go unnoticed for so long, disguising itself as a morphologically similar relative and evading all detection. However this is exactly what the elusive Omura’s Whale (Balaenoptera omurai) did, only being recognized as a new species in late 2003.
In the years that followed several specimens (all of which had either been whaled or found stranded) were identified throughout South East Asia leading researchers to believe the whales distribution was restricted to the Indo-Pacific region.
However, in 2013 the first living Omura’s whale population was discovered off the coast of North-Western Madagascar by Dr. Salvatore Cerchio, making scientists question what little they knew about the whales’ habitat and range. Subsequent research by Dr. Salvatore Cerchio which examined papers and photographic accounts found that the species is more widely distributed than previously thought and occurs in all tropical and warm-temperate ocean basins with the exception of the central and Eastern Pacific.
Even though Omura’s whales seem to be more widely distributed than was previously thought, they are by no means a common occurrence and very little is still known about them; which is why coming across one in the iSimangaliso Wetland Park in 2019 was such a noteworthy moment. It was late March when Sharklife researchers caught sight of a smallish whale whilst freediving on an inshore reef off Sodwana Bay. The whales shape looked familiar to the researchers yet no one knew what it was, the best guess was a Minke Whale (Balaenoptera acutorostrata), the 2nd smallest baleen whale species. Little did they know that they had just encountered one of the world’s most elusive whale species.
Below: Sharklife researchers get a close encounter with the elusive Omura's Whale
Omura’s whales are part of the rorqual family of baleen whales (Balaenopteridae), which includes other species like the Minke and Blue whale. Before they were described as their own species they were often mistaken for small Bryde’s whales (Balaenoptera edenibrydei), which look incredibly similar but are a little bit larger. Omura’s whales also have a single defined ridge on the front of their head, whereas Bryde’s whales have three. In addition to their morphological features, Omura’s whales also exhibit distinctive behaviours that other rorqual whales do not, such as their social and feeding habits.
Below: A Bryde's whale with three ridges on the head - Image Zejulio
According to Dr. Cerchio’s findings, Omura’s whales do not form tight-knit pods, unlike many other whale species, instead they hang around in loose groups within earshot of one another singing low repetitive melody’s. Males have also been observed singing in chorus, perhaps to assert dominance and woo females.
Like all rorqual whales Omura’s whales use their baleen plates (brush-like teeth) to filter small crustaceans and planktonic organisms out of the water column. However according to Dr. Cerchio’s research Omura’s whales do not migrate to colder waters near the poles to feed where planktonic food is abundant.
We still have a lot to learn about the Omura’s whale but thanks to projects such as the Madagascar Omura’s Whale Project new information is surfacing on a regular basis. Hopefully soon we will learn more about what makes this whale stand out and in the meantime others might be lucky enough to catch another glimpse of the eccentric cetacean in the waters of Sodwana.
References:
Global Distribution of Omura’s Whales (Balaenoptera omurai) and Assessment of Range-Wide Threats
Salvatore Cerchio1*, Tadasu K. Yamada2 and Robert L. Brownell Jr.3
Blog Author: Max Schwarz – Sharklife Intern
