Biomimicry: How a Boxfish Caught Mercedes’ Eye

Out on A Swim

‘Out on a swim’ is a coral reef blog that tells the stories of the characters who live under the waves and what has caught my eye when ‘out on a swim’ in the lagoons of Norfolk Island. It is also a record of the difficulties Norfolk Island’s reef faces, like many others around the world, as a result of the poor water quality that has been allowed to flow onto it.

This page shows the most recent blog posts. For the complete catalogue, visit the ‘Out on a swim index’ page.

This blog is rated in the Top 20 Coral Reef Blogs in the world.

If you’ve been following my lagoon wanderings on Facebook (Norfolk Island Time official), you’ll know I have a bit of a soft spot for one particularly adorable resident – Mr Lemonhead, the yellow boxfish (Ostracion cubicus). I first spotted this little guy in March 2024, when he (?) was not much bigger than a grape, and I’ve been keeping tabs on him ever since.

His vivid yellow jacket with black spots is a classic case of warning colouration (aposematism), signalling to would-be predators that he is not going to be very tasty. He secretes a toxic mucus – ostracitoxin – in a cloud of white slime when stressed. This can harm other fish in the vicinity, affecting their red blood cells and gills. He’s filling out now, and before long he’ll probably swap that brilliant yellow suit for something more grown-up as his colouration fades (see image at the end of this post), and maybe he’ll even head off to explore beyond the safety of the lagoon.

While it is tricky to judge the scale from the photos (below), Mr Lemonhead is about three times the size he was back in March 2024.

Mr Lemonhead, the yellow boxfish (*Ostracion cubicus*) 15 March 2024

Boxfish have a very particular look – think of a swimming dice with fins – thanks to their rigid, bony ‘box’ that protects them from all sorts of bother. The funny thing is, for such an awkward-looking creature, Mr Lemonhead can turn on a 5c piece (remember those?) and hover like he’s on invisible strings. All that manoeuvring is down to some pretty clever fin work.

Biomimicry – looking to nature’s designs, processes, and systems for inspiration

Back in the early 2000s, the design boffins at Mercedes Benz took one look at the yellow boxfish and thought, ‘Now that’s a shape for a car’. They imagined a perfect low-drag, high-efficiency design, and as a result, in 2005, they rolled out the Mercedes-Bionic – a car that was sleek, futuristic, and supposedly boxfish-smooth as it sped through the air. Only later did scientists discover the boxfish isn’t especially streamlined at all. Its nimbleness actually comes from being slightly unstable, with those fins constantly making micro-adjustments. So the car never made it to the showroom floor, but it did make people think differently about where good ideas can come from.

Mr Lemonhead is not the only reef local lending ideas to the wider world. Manta rays, for example, have inspired the shape and movement of experimental underwater vehicles. Instead of noisy propellers, these use gentle, sweeping fin strokes – quiet, efficient, and perfect for sneaking up on marine life with a camera. Then there’s the parrotfish, happily chomping away at coral all day. Its fused front teeth are so ridiculously tough that scientists have studied them to create ultra-hard materials for tools and even dental work. Imagine having teeth that could crunch rock and still look like you’ve just been to the dentist!

Blue-barred parrotfish (*Scarus ghobban*) with fused front teeth designed for scraping coral

Next time you’re drifting over the reef, remember – you’re floating above a treasure chest of design inspiration. From boxy little characters like Mr Lemonhead to the gliding giants and the coral crunchers, the lagoon is basically nature’s own R&D lab – and not just for design. Did you know, for example, that many reef animals have also gifted us chemicals for life-saving medicines? But that is a post for another day!

Mercedes-Benz bionic car at Metropolitan Museum of Modern Art: Design and the Elastic Mind, reprinted from Wikimedia under the Creative Commons Attribution-Share Alike 2.0 Generic license.

An adult yellow boxfish. Photo 539545043, (c) Max Carter, some rights reserved (CC BY-NC), uploaded by Max Carter (iNaturalist)

September 6, 2026

Watching El Niño from Norfolk Island

El Niño is strengthening across the Pacific, but that does not tell us exactly what the coming months will bring to Norfolk Island. After a long wet spell, I am watching our rainfall and water supplies more closely again – and, underwater, keeping an eye on sea temperature, algae, coral recruits and the fish that turn up on the reef.

September 2, 2026

What the world’s reefs are telling Norfolk Island

Two major new coral reef reports carry a clear message for Norfolk Island: reefs can recover when pressures ease, but the time available for recovery is shrinking. Norfolk Islanders were raising concerns about water quality, runoff and the health of Emily and Slaughter Bays nearly forty years ago. Today we have much better science, a changing climate and a far clearer understanding of how closely the catchment and reef are connected. This article looks at what that means for water quality, long-term monitoring, dredging and how we manage Kingston from land to sea.

August 25, 2026

When the map changes

A fish once thought to belong only to Norfolk turns up elsewhere; another appears here hundreds of kilometres beyond its known range. Cardinalfishes and a Sabre squirrelfish show how our maps of species distributions are revised.

August 24, 2026

Endemic, native, undescribed – what do these words actually mean?

A Norfolk chromis that turned out not to be Chromis fumea, a blenny found nowhere else, and a tiny goby that may not yet have a name. A look at what we mean by native, endemic, undescribed and newly described – and why scientific names sometimes change.

August 16, 2026

What’s grazing in the green stuff?

A proliferation of Bryopsis on the reef has brought some beautiful little underwater grazers with it. I follow the trail from sap-sucking sea slugs and egg masses to a bigger question – why is there so much Bryopsis around at the moment?

August 8, 2026

The clam beneath Emily Bay

I’ve seen the beautiful shells of Laciolina chloroleuca in Emily Bay for decades, but I’d never really stopped to wonder where the living animals were. It turns out they may be buried half a metre beneath the sand. A closer look at an easily overlooked clam, its extraordinary shell markings, and the hidden life beneath our lagoon.

August 1, 2026

Reflections of an accidental marine scientist

What I thought would be a steady plod towards retirement, with plenty of time spent nursing grandchildren, was abruptly upended exactly six years ago today. This is the story of how an environmental catastrophe changed the course of my life – and led me to reinvent myself. It is a reflection on how, and why, I became an accidental marine scientist.

July 24, 2026

From ridge to reef: unpicking the Waterway and Wetland Strategy

Norfolk Island’s draft Waterway and Wetland Strategy will guide work for the next ten years. I support its intent, but it needs to be clear, practical and measurable – joining the dots from ridge to reef so we know whether public money is improving water quality and helping the reef.

July 13, 2026

Reef reality in pictures

Let the pictures do the talking. This is the reality on Norfolk Island’s reef today, laid out in a two-minute video.

June 28, 2026

The red seaweed behind low-methane beef

A small red seaweed on Norfolk’s reef has become part of a much bigger story. Asparagopsis taxiformis can look like a delicate red feather duster or, at another stage of its life cycle, like a tiny cottony pom-pom. It is beautiful, easily overlooked, and now being used in the cattle industry to help reduce methane emissions. This post looks at the reef oddity behind the low-methane beef story – and why repeated local observation can be more useful than it first appears.