Much about the pygmy right whale remains a mystery, but scientists have made a new discovery about this “rarely sighted” marine enigma that calls the waters off Australia home.
The animals are one of the only whale species not to embark on seasonal migrations to nutrient-rich Antarctic waters, new research led by the University of New South Wales, and published in Frontiers in Marine Science found.
Instead, the whales reside in the temperate waters near Australia throughout the year.
“If you google pygmy right whale, one of the first queries that comes up is whether they are extinct, which illustrates just how little we know about them, and how little known they are,” Adelaide Dedden, lead author of the study and a marine ecologist at UNSW Science, said.
“What’s especially surprising is it turns out these whales are somewhat a resident species, given they appear to be hanging around Australia year-round.”
Researchers came to the discovery by analysing the baleen plates of 14 Australian pygmy right whales, loaned from the South Australian Museum.
The key to solving the puzzle lay in what the animals eat, Professor Tracey Rogers, a marine ecologist at UNSW Science and senior author of the study, said.
“As the baleen grows, biochemical signals from their food called stable isotopes get trapped,” Rogers said.
“These signals don’t decay over time, so it’s like reading a history book about their behaviour, including what they ate and the general area they were in at the time.
From these isotopic records, it was concluded the species likes to hang around the mid-latitude waters year-round off southern Australia, feeding on krill and small crustaceans.
“They’re our little homebodies, just happy to hide away and never leave the comforts of our continental waters,” Rogers said.
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“This makes sense when you look at the slender structures of their baleen plates relative to their body size.”
“They need to draw in as much as possible from these less productive waters around Australia to stay in the region year-round.”
Pygmy right whales are the smallest member of the filter-feeding family, reaching lengths of just 6.5 metres and can weigh around 3.5 tonnes.
Their numbers are believed to be stable as they were never targeted for whaling, however more data is needed on the species.
Starting around June, tens of thousands of humpbacks migrate up Australia’s east coast from Antarctica to warmer waters.
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