The ocean is home to some of the world’s largest and most mysterious creatures, some of whom we’ve known for centuries through epic storytelling and legends.
From the sperm whale in Moby Dick to the giant squid in 20,000 Leagues Under the Sea – the most mysterious giants of the deep, however, are little written about, little talked about, and not only live over 1000 metres below the surface, but their diet consists of deep-sea squid just like Jules Verne’s monsters.
Beaked whales are a group of Odontocetes (toothed) whales, that make up almost a quarter of all cetacean species, aptly named due to their cute dolphin-like beaks. They are one of the largest and most diverse groups of marine mammals, however, are still 90% data deficient.
As deep-sea dwellers with brief and elusive surface behaviour (not like our attention-seeking humpbacks!), these whales are rarely seen alive, with some species only ever identified from their washed-up carcasses. Crazy, huh? From the teeny, weeny, small pool of studies done on these mysterious animals, we may not know much, but what we do know is that they are fascinating. One of the only long-term studies on beaked whales managed to record a new mammalian dive depth AND duration record: a whopping 2992 metres over 137.5 minutes by a Cuvier’s beaked whale, a record previously held by the southern elephant seal at 2388 metres and 120 minutes.
That’s almost 3 km…by an air-breathing mammal! This study was less than ten years ago, and part of the slow trickle of data, including a new beaked whale species discovered in New Zealand only last year.
So why choose to live your life so far hidden under the sea, surely inconvenient for a mammal, right?
Well, you could ask this question about many different species. Why do some animals thrive in the arctic, while some call the hottest and most barren deserts home? The answer is that these animals fill an ecological niche. They’ve adapted to live in these places for various reasons, including predator evasion, food sources (squids galore!) and individual life histories.
For beaked whales, living at these depths helps them avoid their greatest predator, killer whales - or orcas. Orcas have been observed hunting beaked whales close to the surface, and generally hunt in the first few hundred meters of the water column. Orcas do occasionally dive deeper, but then need hours to recover as they just aren’t cut out for it like our beaked friends (it’s okay, Orca. Me neither).
Adaptations that allow beaked whales to be at home in the abyss include better storage of oxygen in blood and tissues to allow them to breathe less frequently, remarkably short gas intervals, the ability to tuck their flippers into special grooves to reduce drag (like real-life mammal torpedoes!), and reduced air pockets in their body that would ordinarily lead to crushing under pressure and ‘the bends’.
Unfortunately, even at depths safe from just about everything else, there is plenty of evidence that beaked whales are massively under threat from human impacts (sigh).
Due to their deep-sea lifestyle, beaked whales are extremely vulnerable to seismic activity, ship noise pollution and naval sonar disturbances.
These activities force the whales to surface dangerously fast, causing mass strandings and fatalities all over the world.
Many beaked whale autopsies have also found huge quantities of plastic in their stomachs, as well as high levels of trace metals and other contaminants - which is where my studies come in.
There have been at least eight beaked whales stranded on the New South Wales coast (Australia) in recent years. These strandings are incredibly rare, and while wild weather may have played a part in January’s strandings, toxic effects from pollution cannot be ruled out, especially given results from my earlier study hinting at trace metal toxicity.
While this last toxicology study had a fairly broad group of whales, my current study has a focus on our beaked friends, including all of these recent strandings as well as about six earlier ones dating back to 2007.
On top of trace metals, which you can read about in my earlier blog, I’ll also be testing for organic pollutants, which is a whole other kettle of fish (or whales?) for another time.
The lack of knowledge on beaked whales is one of their greatest threats, so any data collected is incredibly important given we have little to no baselines for virtually everything ranging from populations and life history to biology and toxicology.
With their elusivity in mind, it’s not surprising that this will be the first study of its kind in Australia, and possibly on an even larger scale.
They may not be poster children like many of their cetacean buddies (I don’t know if you guys had 90s rainbow dolphin posters in your room growing up, but I definitely did…), but as apex marine predators and just super cool marine mammals, beaked whales deserve a little more limelight, a little more consideration and a LOT more protection, which will only come with further study to bridge that ‘data deficient’ gap.
So next time you’re at a family dinner, on a first date or find yourself on the radio, be sure to drop those record-breaking dive figures and do your bit to help get the word out.
I promise they’ll be impressed!
If you liked this article, go check out my other article on “A Future Without Cetaceans? Why You Should Care About Marine Trace Metal Toxicity”.
Natalie Palmer
BIO:
Veterinary nurse, graduate Marine and Environmental Scientist, undertaking Hons in cetacean toxicology.
References
Amos, J. (2014). Beaked Whale is deep-dive champion. BBC. retrieved from https://www.bbc.com/news/science-environment-26743090
Li, & Rosso, M. (2021). Lack of knowledge threatens beaked whales. Science (American Association for the Advancement of Science), 371(6531), 791–791. https://doi.org/10.1126/science.abg8922
Schorr, Falcone, E. A., Moretti, D. J., & Andrews, R. D. (2014). First long-term behavioral records from Cuvier’s beaked whales (Ziphius cavirostris) reveal record-breaking dives. PloS One, 9(3), e92633–e92633. https://doi.org/10.1371/journal.pone.0092633
Wellard, Lightbody, K., Fouda, L., Blewitt, M., Riggs, D., & Erbe, C. (2016). Killer Whale (Orcinus orca) Predation on Beaked Whales (Mesoplodon spp.) in the Bremer Sub-Basin, Western Australia. PloS One, 11(12), e0166670–e0166670. https://doi.org/10.1371/journal.pone.0166670