Extremely rare whale 'hidden in plain sight' in Australian waters
Once thought to be extinct, we now know where pygmy right whales are spending their days.
It’s a species seen alive on fewer than 30 occasions, but pygmy right whales have actually been quietly swimming around Australia's waters unobserved.
“Hiding in plain sight,” is how marine biologist Adelaide Redden describes their behaviour.
She’s the lead author of the study about where they go when the weather heats up. While larger whales migrate to cooler Antarctic waters, it seems their tiny cousins actually stay behind.
While we don’t necessarily know exactly where they go during the hotter months, what’s clear is they stay in more temperate waters, and we can tell that from the food they eat.
"We don't know if they're moving between say New Zealand and Australia or if those two populations are genetically distinct," Ms Redden said.
How do we know what the pygmy right whales eat?
As you probably guessed, it’s not through studying living specimens of the “mysterious” marine mammals that researchers have made their discovery about their movement.
While live sightings are rare, pygmy right whale carcasses do wash up on beaches occasionally and the South Australian Museum loaned its small collection to the research team.
The University of NSW-led team analysed the slender bristles in the whales’ baleen mouth plates which filter in the tiny krill they eat.
“As the baleen grows, biochemical signals from their food called stable isotopes get trapped,” marine ecologist Professor Tracey Rogers explained. “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.”
By analysing the isotopes contained in the whale specimens, the researchers were able to look at the species’ movements over a period of almost 40 years. They found no evidence the whales had been eating food found in Antarctic waters.
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How rare are pygmy right whales?
While they’re currently categorised as Least Concern on the International Union for Conservation of Nature's Red List of threatened species, population trends and numbers are unknown. Until a decade ago it was believed the species could have been wiped out.
“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,” Ms Redden said.
She describes the species as “quite small and inconspicuous”, and they look remarkably like another species of whale that’s more commonly sighted.
“They look quite similar to minke whales, so there’s been some confusion in the past,” she told Yahoo. “It could be possible that other people are sighting them and calling them minke whales, but they do have a distinctive arched jaw-line.”
Ms Redden describes her research as “foundational knowledge” that will hopefully lead to more investigation of the whales which she describes as “homebodies in our waters”.
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