In our imagination, animal reproduction follows simple rules: a male, a female, and the continuation of the species. But in the Indian Ocean and beyond, life has developed strategies that overturn these certainties. Some species can change sex depending on their position in the social hierarchy. Others, in the total absence of a male, can give birth entirely on their own. These stories, which sound like science fiction, are in fact very real.
The Clownfish: A World Ruled by FemalesPopularized by the movie Finding Nemo, the clownfish has become one of the most famous ambassadors of the underwater world. Yet the film deliberately ignored a striking biological truth: in every anemone, it is a female that reigns supreme.
Their society is strictly hierarchical. The largest fish is the dominant female. Next comes a smaller breeding male, followed by a series of immature males waiting their turn. If the female dies, the breeding male changes sex and becomes female. One of the immature males then rises to take the vacant breeding role. This phenomenon, called protandry, makes clownfish champions of biological flexibility. It ensures the colony’s survival — no group is ever left without a female. But it also challenges our notion of what is “natural.” Here, nature doesn’t freeze roles; it adapts them to the ecosystem’s needs. 
Sharks: Giving Birth Without a PartnerIf clownfish are masters of flexibility, sharks push the limits of biological imagination even further. In several aquariums around the world, biologists have observed female sharks giving birth despite the complete absence of a male.
The first documented case dates back to 2001, with a bonnethead shark (Sphyrna tiburo). Since then, the phenomenon has been confirmed in other species: the zebra shark (Stegostoma tigrinum) and the leopard shark (Triakis semifasciata). DNA testing revealed that the offspring were indeed produced by a single female, without any male contribution. The mechanism is known as parthenogenesis. In simple terms, the egg fuses with a polar body — a by-product of cell division during meiosis. The result is a viable embryo, but with reduced genetic diversity: the pup inherits only maternal DNA. This form of “virgin birth” is not a miracle solution. It allows a solitary female to pass on her genes, but it does not guarantee the long-term survival of a species. A population that reproduces exclusively through parthenogenesis would quickly face the risks of inbreeding. 
When Biology Outruns FictionThese phenomena may seem anecdotal, but they reveal much about life’s creativity. Marine biology is not locked into binary patterns; it is constantly experimenting, adapting, and reinventing.
For clownfish, sex change is a safeguard for colony survival. For sharks, parthenogenesis is an emergency fallback when no mates are available. Both strategies showcase extraordinary resilience. Yet they also reveal the limits of that resilience. In today’s ocean — disrupted by climate change, overfishing, and habitat destruction — such mechanisms are not enough to save threatened species. They are biological stopgaps, not permanent solutions. 
Lessons for UsWhat can we take from these stories, beyond their fascination?
First, they remind us that nature is infinitely more inventive than our cultural models. The notions of “male” and “female,” fixed in our minds, are in fact variables in the ocean — roles adapted to circumstances. Second, they show that the survival of a species does not depend only on extraordinary biological tricks. It depends above all on the environment in which the species lives. A clownfish can change sex, a shark can give birth without a mate — but if their reefs vanish, if their oceans are emptied of fish, no adaptation will be enough. Finally, they push us to reflect on our role. Observing these biological marvels should inspire awe, but also responsibility. Protecting habitats, limiting human pressure — that’s what gives these species the chance to display the full ingenuity of life. 
Clownfish and sharks teach us a paradoxical lesson: nature can reinvent itself, but it is not invincible. Each strategy has its limits.
In a world where the ocean is changing at unprecedented speed, it is not enough to marvel at curiosities of biology. We must protect the conditions that allow them to exist. Because behind every camouflage, behind every fatherless birth, lies a simple truth: without a healthy ocean, even the miracles of biology fade away. FAQ – Clownfish Sex Change & Shark ReproductionQ1.How long does it take for a male clownfish to change sex?Behavioral change occurs within 1–3 days after the dominant female disappears. Gonads become functional female organs in 2–3 weeks, and full fertility is usually reached in 4–8 weeks. Q2.How many marine species can change sex? Examples?More than 500 fish species (≈2% of teleosts) can change sex:
Q3.Does sex change occur on land in the animal kingdom?Among terrestrial vertebrates, social sex change like in clownfish is extremely rare. However:
In mammals and birds, sex change does not occur naturally. Q4.How long does it take for a female shark to lay eggs or give birth?Oviparous sharks (e.g. catsharks, zebra sharks): lay 1–2 egg cases every 1–3 weeks during the season; incubation lasts 3–6 months (sometimes up to 12). Viviparous/ovoviviparous sharks (e.g. hammerheads, lemon sharks): pregnancy lasts 10–12 months, and in some species up to 18–24 months. 
At dawn, the lagoon of Wallis shimmers in soft pastel tones, the crow of roosters echoing through coconut groves. Soon, the steady toll of church bells drifts across the humid air, calling villagers to morning mass. On this small Polynesian island in the South Pacific, faith and tradition are inseparable from the rhythm of everyday life.
An island anchored in faithCatholicism arrived with missionaries in the 19th century, and today it remains the heartbeat of Wallisian identity. Every village has its own church, often perched by the water’s edge, its spire rising above breadfruit trees. On Sundays, families dressed in bright lavalava fill the pews, their polyphonic hymns lifting into the rafters. Religion here is more than private devotion — it is the collective pulse of the island.
The power of customAlongside the church stands another pillar of Wallisian society: la coutume. Rooted in Polynesian tradition, it dictates respect for hierarchy, rituals of welcome, and the authority of chiefs. At its centre is the Lavelua, the customary king. Wallis is the only French territory where a monarchy still exists, coexisting with the institutions of the Republic. Though the king holds no political power in the French state, his moral and symbolic authority is immense. It is a reminder that here, tradition has not bowed to modernity.
Wealth measured in pigsOn Wallis, prosperity is not counted in banknotes but in livestock. Pigs are the ultimate currency of respect and social standing. During major ceremonies, families present them as gifts — the more pigs offered, the greater the prestige. To raise pigs is to invest not only in food, but in reputation and influence.
A lagoon of endless bluesBeyond the villages, the lagoon unfurls in shades of turquoise and cobalt, dotted with tiny motu fringed with coral. Outrigger canoes glide silently across the shallows, fishing nets trailing behind. Life moves slowly here: coconuts fall, waves lap basalt shores, and the outside world feels far away.
The mystery of Lake LalolaloInland, hidden by dense forest, lies a perfect circle: Lake Lalolalo. This volcanic crater, its cliffs plunging more than thirty metres down to dark waters, is steeped in legend. Some say it is bottomless, others that it shelters spirits or mythical creatures. Even today, the lake has a gravity of its own — a silence broken only by the call of birds. For visitors, it offers a striking counterpoint to the brilliance of the lagoon: the secret, more enigmatic face of Wallis.
Where time holds steadyAs night falls, the island gathers once more — for prayer, for kava, for shared meals where roast pig feeds dozens and laughter echoes under the stars. Wallis may be a French territory, but it is first and foremost a Polynesian homeland, where religion, custom, monarchy and community are deeply interwoven. Time seems to hold steady here, anchored in faith and tradition, while the rest of the world rushes ever faster.
Why is Wallis unique in France?Wallis is the only French territory that still has a customary king, the Lavelua, whose authority coexists with the French Republic.What role does religion play in Wallis?Catholicism, introduced in the 19th century, remains central to daily life. Every village has a church, and mass is an important community event.Why are pigs important in Wallis?Pigs are considered a symbol of wealth and respect. They are offered during ceremonies and function as a form of social currency.What is Lake Lalolalo?Lake Lalolalo is a volcanic crater lake surrounded by cliffs, known both for its natural beauty and its legends. It is one of the island’s most remarkable sites.
Andasibe – Voices of the Forest
Rain filters through the emerald canopy, dripping from leaf to leaf before vanishing into the dark soil. In Andasibe’s primary forest, the air is saturated with the scent of wet earth, orchids, and moss. Mist clings to the trunks, blurring the line between the living and the ancient. Then, from somewhere deep in the shadows, a sound rises — low, haunting, impossibly pure. It is the call of the indri (Indri indri), the largest of Madagascar’s lemurs, carrying through the forest like a hymn from another time. For a moment, everything holds still.
Madagascar is home to around 112 species and subspecies of lemurs, all found nowhere else on Earth. Unlike monkeys — their distant evolutionary cousins — lemurs are strepsirrhines: they have a more developed sense of smell, a wet nose, and, in many species, eyes adapted to low light. Isolated here for millions of years, they evolved into a dazzling variety of forms, from the bamboo lemurs that cling to slender stalks, to the diademed sifakas that leap more than ten meters between trees.
In Andasibe, the indri shares its forest with the golden bamboo lemur (Hapalemur aureus), the smaller eastern grey bamboo lemur (Hapalemur griseus), and the spectacular diademed sifaka (Propithecus diadema), whose silky white-and-gold fur flashes through the canopy. Hidden among the trunks are masters of camouflage: the leaf-tailed gecko (Uroplatus fimbriatus), flat-bodied with frilled edges that erase its shadow, and the male panther chameleon (Furcifer pardalis), ablaze in reds, greens, and blues that shift with mood and light.
Yet even this sanctuary is shrinking. Rice paddies and cassava fields push ever closer to the forest edge. Fresh stumps mark recent logging, and narrow red-dirt trails cut deeper into the trees. In the past fifty years, Madagascar has lost nearly 40% of its forest cover, and Andasibe now feels like an island of biodiversity adrift in a sea of human pressure. Each morning, when the indri calls, it does so in a forest slightly smaller than the day before.
The Pangalanes – Life on the Water
Leaving the highland forest behind, the road winds east until the hills open into a patchwork of calm waters, reed-fringed lagoons, and narrow channels. This is the Pangalanes Canal, a 600-kilometer artery linking lakes and rivers along Madagascar’s east coast. Here, life is measured in paddle strokes. At dawn, fishermen set out in narrow wooden pirogues, their movements smooth and unhurried. The boats return heavy with shrimp, silver-scaled fish, or green bananas. Stacked high on some decks are bamboo shrimp traps — woven cylinders that sink into the canal overnight and are hauled up at first light, emptied by quick, practiced hands. Farther along, floating nets mark family fishing grounds, their lines stretching across the water like strands of a web. On the banks, daily life revolves around the canal. Children bathe near moored pirogues. Women wash clothes, rhythmically slapping them against wooden planks. Men carve new paddles from freshly cut logs. Trade happens boat-to-boat — a basket of shrimp swapped for fruit, a greeting exchanged midstream. The canal feeds both bodies and livelihoods, but every fish caught, every shrimp lifted from the traps is also one less piece of the ecosystem’s fragile puzzle. 
The Night Wanderer
Night falls quickly here. Cooking fires flicker on the banks, and the canal turns to black glass under the moonless sky. Our pirogue moves almost silently, the paddle’s dip the only sound. At the bow, our guide, Roméo, sweeps a flashlight over the low branches. Two orange points flare in the beam — unmoving, unblinking. The aye-aye (Daubentonia madagascariensis). It moves forward slowly, its dark fur streaked with silver, its large ears swiveling like satellite dishes. Its most unusual feature is the elongated middle finger — a finely tuned tool. The aye-aye taps the bark, listening for the hollow resonance of insect larvae hidden within. When it detects a target, it gnaws a small hole with rodent-like incisors and slips in its spidery finger to hook its prey. Feared in some villages as a harbinger of misfortune, the aye-aye is, in fact, a vital forest engineer, recycling dead wood and controlling wood-boring insects. To see one here, unhurried and unafraid, is to witness both resilience and fragility in a single moment. Then, with a silent leap, it melts back into the dark. 
An Uneasy Balance
Along the Pangalanes, human life depends on the same resources that sustain its wildlife. The shrimp and fish caught here feed entire families and supply the restaurants catering to travelers drawn by Madagascar’s rare species. This economy is essential — but it rests on daily extraction that offers little time for the ecosystem to recover. Fine Art Wildlife What We Lost — CollectionA curated series of wildlife fine art prints — memory, loss and resilience. Museum-grade papers, archival inks, limited editions. Shop the collection
The contradiction is stark. At night, guides lead trips to glimpse the aye-aye, an animal protected by law and celebrated for its rarity. By day, in the same waters, traps and nets blanket the canal to meet the rising demand from tourism and local markets.
On land, the pressure is just as intense. Trees felled in surrounding forests are used to build homes for new arrivals seeking work near hotels. What begins as a temporary settlement often becomes permanent, eating further into the forest edge. Every tree taken for a wall or roof is one less shelter for lemurs, pushing species like the indri and sifaka into smaller, more fragmented habitats.
The Pangalanes distills Madagascar’s central paradox: a rare animal revered and protected, a human community reliant on natural abundance, and an environment quietly diminishing. The survival of this fragile Eden depends on finding a delicate balance between protection and subsistence, between immediate need and long-term vision. Until that balance is found, each indri’s call and each fleeting glimpse of an aye-aye remain both a miracle — and a warning.
A small island that became legendary
At the northern tip of Cebu lies Malapascua Island — a quiet fishing village with sandy beaches and simple bangkas resting on the shore. Life here flows at a slow pace, far from mass tourism. Yet Malapascua has become a legendary name in the diving world. The reason can be summed up in two words: thresher shark. 
4h30 am saling to tresher shark
The star of Malapascua: the thresher sharkEverything happens at Monad Shoal. Before dawn, boats leave the island and divers descend into the dark. As the sun rises, the sharks slowly appear, rising from the deep blue.
One evening over dinner, my guide Arnel tells me: “Back in the 1990s, we had more than 350 thresher sharks here. Fishermen decimated the population — today only around 70 remain.” A chilling reminder of how fragile this encounter really is. 
Cleaning session at 10 meters deep
The thresher shark is truly one of the most beautiful sharks in the ocean: a singular, elegant line, its silhouette stretched by an impossibly long tail. Alongside the tiger shark, it’s one of my personal favorites. But in Malapascua, it must be earned. To see it, you wake up at dawn as these sharks rise from the depths to be cleaned by wrasse. They linger near the reef for about an hour before vanishing back into the abyss.
For me, Malapascua means three things: the thresher shark, macro photography, and the soft corals. Hippocampus, harlequin shrimps, flamboyant nudibranchs — macro lovers will be in heaven. A word of advice, though: skip the crowded evening dives for harlequin shrimps. Too many divers, stressed animals, and very little to see in good conditions. 
Art of camouflage
Other must-dive sites around Malapascua
Soft corals place
Beyond diving: island lifeMalapascua remains laid-back and authentic. You get around on foot or by motorbike, share meals with locals, and enjoy a simple island rhythm. Off the water, excursions to Kalanggaman Island or walks along quiet beaches complete the experience.
Practical travel tips for divers
Conclusion: why Malapascua is worth itDiving in Malapascua is a once-in-a-lifetime experience: watching a thresher shark rise from the depths at sunrise. Fragile, surreal, unforgettable. Add to that world-class macro life, soft coral gardens, and a peaceful island vibe, and Malapascua rightfully earns its place as one of the best diving destinations in the Philippines.
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Serge Melesan
Underwater & Fine Art Ocean Photographer Specialist in Fine Art Ocean Photography. Published in Oceanographic Magazine & Earth.org. National Geographic Traveller – Portfolio Winner (2023). Archives
Novembre 2025
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