Nature's Most Outrageous Underwater Sex Show

“The first time you go and stick your head underwater and you see hundreds and hundreds of cuttlefish in that little area, it looks like a chaotic kaleidoscope,” says Bramley.

As the owner of Whyalla Diving Services and a decades-long supporter of the Australian giant cuttlefish, Bramley has watched the colorful mating frenzy of cuttlefish in Spencer Gulf North Marine Park in South Australia for years.

It used to be only of interest to local fishermen and divers, who would spread the word to each other that “the cuttlefish have arrived”.

Now, that marine phenomenon is attracting tourists and researchers from around the world to the small steel town of Whyalla, on the Eyre Peninsula in South Australia.

The cuttlefish, a type of marine invertebrate closely related to the octopus, it is an intelligent mollusk that can change color and texture instantly.

They are known to solve puzzles and can hypnotize their prey. turning its body into strobe lights, rapidly emitting colors through its skin to distract and stun an unsuspecting crab or fish.

Their camouflage abilities put chameleons to shame and they have even attracted the attention of the US Army, which has investigated the color-changing abilities of cuttlefish with the idea of ​​replicating their techniques for military use.

If that's not unusual enough, their mating behaviors are strange, to say the least.

spectacular event

From May to September each year, hundreds of thousands of giant Australian cuttlefish gather in the waters near Point Lowly, in the northernmost part of Spencer Gulf, for the sole purpose of mating.

Getty Images
Point Lowly Lighthouse.

It is then that Whyalla becomes the scene of the Show of the most extravagant underwater sex and one of the most spectacular events in nature: the spawning of the giant Australian cuttlefish.

The world's largest cuttlefish are found in the waters off southern Australia, but only in Whyalla do they gather in large numbers to mate.

"An estimate of the number of cuttlefish amassing in 2020 was 247,000, the highest on record," said Professor Bronwyn M. Gillanders, a leading cuttlefish researcher and director of the University of Adelaide's School of Biological Sciences.

"That's the reported number, but we know it's likely to be an underestimate."

According to Gillanders, Whyalla attracts cuttlefish due to its unique seascape.


Carl Charter
The Sepia apama is the largest cuttlefish in the world, reaching 50 centimeters in length.

The northernmost section of Spencer Gulf offers many rocky ledges that the females use to lay their eggs. And, although cuttlefish mate in other places, this is where they do it the most on the planet.

There is no other place in the world where such spectacular and bizarre mating behavior can be observed en masse, including color changes and males who dress up of females.

No one said finding a partner was easy—and these cuttlefish are single and unattached—but the first thing they need to do is get to the party.

Bramley explained that some of the cuttlefish were tagged and found that some travel at least 40 miles south of the city and others 20 miles north to reach breeding grounds in northern Spencer Gulf.

In the front row

Diver observing cuttlefish

Carl Charter
Mass spawning was a relatively unknown marine phenomenon until the early 2000s.

For divers, even those who dive without oxygen, with only a tube to breathe, it is easy to observe the cephalopods, as they congregate just off the coast, between 2 and 6 meters.

But although the water is calm, it is not lukewarm.

“You really have to dress for the occasion,” Bramley said, laughing.

With ocean temperatures hovering around 10-16 degrees Celsius, I came prepared with a thick wetsuit, hood, gloves, and booties. Still, the cold hit me like a ton of bricks, but once I was in the water, I was front row for the most amazing show in town.

Once my eyes adjusted, I realized that I was surrounded by cuttlefish no they seemed the least bit bothered by having a human watching their most intimate moments.

Males fighting over a female.

Science Photo Library
Males fighting over a female.

With vibrant and vibrant rainbows of purple, orange, turquoise and pink and tentacles everywhere, it took me a while to understand their seduction ritual, as cuttlefish have various tricks to get a mate.

cunning vs. force

In an environment where males can outnumber females 10 to 1, competition to pass on genes is fierce.

In most species, size matters: large, aggressive males fight rivals for a chance to mate. This is also seen in cuttlefish, and large males have been known to fight each other for dominance in the presence of a female.

"The smaller males have a dilemma on their hands, because they know they can't win against the much larger ones," explained Sarah McAnulty, a squid biologist at the University of Connecticut.

“They have devised an alternative approach: pretend to be female to avoid the battleto“.

Australian giant cuttlefish

Getty Images
Fight or dress up?

On perhaps the most fascinating mating behavior of any speciesSmaller males may fade their translucent coloration and change to the speckled maroons and whites of a female, before tucking their billowing arms into their bodies.

This makes them look feminine, and while the big males are busy fighting and leaving their potential mate unattended, the little ones dart to gain access to the female and then quickly change their color back to that of the males: a victory for the cunning underdog.

brain vs. muscles

If the female decides to mate, the spectacle makes you wonder if the cuttlefish has been taking notes from an adult movie.

During the entangled twisting of the tentacles, the cuttlefish connects and the male deposits his sperm packet into the female's mouth, using a specially designed tentacle known as hectocotylus.

The female then holds onto the sperm until she is ready to lay her eggs.

Cuttlefish mating

Getty Images
The long-awaited moment.

The female mates with multiple males and may use a mix of different sperm pools for her clutch.

"It's the ultimate rebuttal to putting all your eggs in one basket," McAnulty said.

Interestingly, females prefer smaller males over their stocky counterparts, according to McAnulty, indicating they are selecting for brains over brawn.

“Studies have even shown that when the females go to lay their eggs, give a higher paternity ratio to those cunning males", said.

"So when we wonder how those blessed cephalopods got so smart, well, they're sexually selecting for it!"

Cuttlefish close-up

Richard Ling
Their brains and eyes are highly developed.

The future

While there's no shortage of X-rated action underwater, it hasn't always been that way.

In recent decades, overfishing in the region has reduced the local cuttlefish population and encouraged locals to take action.

This led to the creation of a fishing exclusion zone in 2013 along the northern section of Spencer Gulf during mating season.

In the late 1990s, numbers were at an all-time low, with Bramley estimating that a mere 30,000-40,000 cuttlefish were present in 1999.

In a twist of fate, the decline in the cuttlefish population attracted media attention.

underwater image

Getty Images
The site of the annual festival of cuttlefish…and of humans.

Once word spread about Whyalla's incredible cephalopods, the region slowly began to attract divers and tourists in the early 2000s, eager to observe what was then a relatively unknown marine phenomenon.

In recent years, the peak cuttlefish season has resulted in hotels and restaurants enjoying full capacity, and the infusion of funds for tourism has been a welcome boost to an economy that relies heavily on steel production.

While there has been talk of building more hotels to handle the influx of tourists, cuttlefish season only lasts three to four months. So how do tour operators sustain themselves for the rest of the year?

One solution the city hopes will help is improving infrastructure, with a $4 million Cuttlefish Sanctuary Conservation and Tourism Project grant announced in 2021.

This will help the city manage the additional visitors each season and promote Whyalla as a nature tourism destination with easily accessible beaches and walking trails, better signage, more native vegetation, and greater protection for the area's delicate ecosystems.

While cuttlefish tourism in Whyalla is only in its second decade, the town hopes it will become a viable long-term source of income.

As for the cuttlefish, we can only hope they continue their swanky, sexy antics, proving that life can be as colorful and wild as you want it to be.

* This story was originally published on BBC Travel. Read the article in English here.

Remember that you can receive notifications from BBC World. Download the new version of our app and activate it so you don't miss out on our best content.

Author Profile

Nathan Rivera
Allow me to introduce myself. I am Nathan Rivera, a dedicated journalist who has had the privilege of writing for the online newspaper Today90. My journey in the world of journalism has been a testament to the power of dedication, integrity, and passion.

My story began with a relentless thirst for knowledge and an innate curiosity about the events shaping our world. I graduated with honors in Investigative Journalism from a renowned university, laying the foundation for what would become a fulfilling career in the field.

What sets me apart is my unwavering commitment to uncovering the truth. I refuse to settle for superficial answers or preconceived narratives. Instead, I constantly challenge the status quo, delving deep into complex issues to reveal the reality beneath the surface. My dedication to investigative journalism has uncovered numerous scandals and shed light on issues others might prefer to ignore.

I am also a staunch advocate for press freedom. I have tirelessly fought to protect the rights of journalists and have faced significant challenges in my quest to inform the public truthfully and without constraints. My courage in defending these principles serves as an example to all who believe in the power of journalism to change the world.

Throughout my career, I have been honored with numerous awards and recognitions for my outstanding work in journalism. My investigations have changed policies, exposed corruption, and given a voice to those who had none. My commitment to truth and justice makes me a beacon of hope in a world where misinformation often prevails.

At Today90, I continue to be a driving force behind journalistic excellence. My tireless dedication to fair and accurate reporting is an invaluable asset to the editorial team. My biography is a living testament to the importance of journalism in our society and a reminder that a dedicated journalist can make a difference in the world.