Lodoicea maldivica, commonly called the coco de mer or double coconut, produces the largest seed of any plant on Earth, with individual seeds weighing up to roughly 25 kilograms. This extraordinary palm grows naturally on just two small islands in the Seychelles archipelago, and the evolutionary story behind its giant seed involves millions of years of isolation, the absence of any animal large enough to carry the fruit away, and a surprisingly clever nutrient-harvesting strategy that feeds both the parent tree and its offspring.
How Big the Seed Actually Is
A mature coco de mer fruit takes six to seven years to develop on the tree and can grow to around half a meter in length. The seed inside, shaped like a pair of fused lobes that give the palm its “double coconut” nickname, typically weighs between 15 and 25 kilograms, though exceptional specimens push beyond that range. For comparison, the seed of an ordinary coconut weighs roughly one to two kilograms. The coco de mer seed is not just heavier than every other seed; it is heavier by an order of magnitude. No other plant comes close.
The fruit itself is also massive, encased in a thick, fibrous husk. Unlike ordinary coconuts, which float and colonize distant shorelines, coco de mer fruits are too dense to drift across open ocean for any useful distance. They sink. This inability to travel by sea is central to why the palm exists on only two islands and why the seed evolved to be so large in the first place.
Why the Seed Grew So Large
The leading explanation for the coco de mer’s extreme seed size centers on an evolutionary feedback loop driven by the absence of dispersal. Most plants benefit from producing many small seeds that animals carry far from the parent, reducing competition between siblings. Lodoicea never had that option. Its seeds are too heavy for any known animal to transport, and they do not float. Seedlings germinate right beneath the parent tree or very close to it.
In that situation, producing many seeds becomes counterproductive because the seedlings crowd one another and compete for the same patch of light and soil. Researchers have argued that ancestral Lodoicea plants producing fewer, larger seeds were more successful than those producing many smaller ones, because each individual seedling received a bigger resource package and had a better chance of surviving the intense local competition. With no dispersal agent to check this trend, the feedback loop continued over millions of years, pushing seed size toward the extreme we see today.1PubMed Central. On the origin of giant seeds: the macroevolution of the double coconut (Lodoicea maldivica) and its relatives
Broader evolutionary analyses of the coco de mer’s relatives in the palm tribe Borasseae support this picture. Across the group, taller plants with fewer-branched flower clusters tend to produce larger seeds, and seed size has generally evolved faster on islands than on continents. Shade-tolerant species within the group also tend toward larger seeds, consistent with the idea that competing in low-light forest understory favors a big initial nutrient investment in each seedling.1PubMed Central. On the origin of giant seeds: the macroevolution of the double coconut (Lodoicea maldivica) and its relatives
A Tree Built to Feed Itself and Its Young
The coco de mer palm does not simply rely on the soil beneath it. Its enormous fan-shaped leaves, which rank among the largest of any palm, are arranged in a funnel that points upward and inward toward the trunk. This architecture intercepts airborne particles, including pollen and organic debris, and channels them down to the base of the trunk when rain washes through the canopy. The result is a self-built nutrient catchment that enriches the soil right where it matters most.2PubMed. The nutrient economy of Lodoicea maldivica, a monodominant palm producing the world’s largest seed
This matters because the granitic soils on Praslin and Curieuse, the two Seychelles islands where coco de mer grows naturally, are ancient and nutrient-poor. A palm that can scavenge nutrients from the atmosphere and concentrate them at its base has a meaningful advantage. The benefit extends beyond the parent tree itself: because seedlings germinate right at the trunk base, they tap into the same enriched soil. The giant seed provides enough stored energy for the seedling to survive for years while it establishes roots in this improved patch of ground. It is a tightly coupled system in which the parent’s leaf architecture and the seed’s enormous nutrient reserve work together to give offspring a fighting chance.
Mature coco de mer palms can reach about 30 meters in trunk height, and their estimated lifespan is around 200 years. Growth is slow, roughly 15 centimeters of trunk per year, and a palm may take about 64 years to transition from juvenile to reproductive adult.3Forest Ecology and Management. Sustainable harvesting of coco de mer, Lodoicea maldivica, in the Vallée de Mai, Seychelles That means a coco de mer planted today might not produce its first fruit until the second half of this century. This glacial pace of maturation compounds every other conservation challenge the species faces.
Pollination and the Struggle to Reproduce
Coco de mer is dioecious, meaning individual palms are either male or female, never both. Male trees produce long, catkin-like flower clusters that serve as a year-round food source for Seychelles wildlife. Researchers have observed bees, flies, slugs, and even geckos visiting the male inflorescences, though trigonid bees appear to be the most likely natural pollinator.4Journal of Botany. Observations on the Morphology, Pollination and Cultivation of Coco de Mer (Lodoicea maldivica) Wind may also play a role, but the heavy, sticky pollen of the coco de mer seems poorly suited to long-distance wind transport.
Successful fruit set depends heavily on proximity to male trees. Studies in the Vallée de Mai, the main protected coco de mer forest on Praslin, have found that fruiting success rises with the number of nearby males and drops as the distance to the nearest male increases. In degraded or fragmented habitat, where forest has been replaced by open shrubland, the nearest male may be far enough away that pollen availability becomes a bottleneck. Fruit set in these degraded areas is lower, and a higher proportion of fruits develop abnormally and fail to mature.5PubMed Central. Tracing coco de mer’s reproductive history: Pollen and nutrient limitations reduce fecundity
The reasons for abnormal fruit development are not fully understood. One hypothesis is a lack of compatible pollen in small or isolated populations, which would make the reproductive bottleneck even tighter than simple distance suggests. Either way, the species is a slow reproducer under the best conditions: a six- to seven-year fruit development time, decades to reach maturity, and dependence on having male trees nearby. Remove any of those pieces and the population’s ability to replace itself erodes quickly.
Where It Grows and How Many Are Left
The entire natural range of Lodoicea maldivica consists of the islands of Praslin and Curieuse in the Seychelles, a granite archipelago in the western Indian Ocean. The largest remaining population occupies the Vallée de Mai on Praslin, a UNESCO World Heritage Site since 1983. Smaller stands survive on Curieuse and in fragments across Praslin outside the reserve.
As of the most recent comprehensive surveys, roughly 27,000 individual coco de mer palms exist in the wild. That number sounds robust until you look at the age structure: about 70 percent of those 27,000 are juveniles, and only around 14 percent are adult reproductive females.3Forest Ecology and Management. Sustainable harvesting of coco de mer, Lodoicea maldivica, in the Vallée de Mai, Seychelles Because it takes decades for a juvenile to begin producing seeds, the actual breeding population is much smaller than the total count suggests. The species is classified as Vulnerable on the IUCN Red List and is protected under Seychelles national law.
Genetic studies of the remaining populations reveal moderate overall genetic diversity, with about 91 percent of genetic loci showing variation. Most of that diversity exists within individual populations rather than between them, which means the different stands on Praslin and Curieuse have not diverged dramatically from one another. However, the Curieuse population does show somewhat lower genetic diversity than the Praslin populations, a pattern consistent with smaller population size and greater isolation.6Diversity and Distributions. Morphological and genetic differentiation in populations of the dispersal-limited coco de mer (Lodoicea maldivica) For a species that cannot disperse its seeds across water, even the few kilometers of ocean between Praslin and Curieuse represent a meaningful genetic barrier.
Poaching, Harvesting, and the Black Market
Coco de mer nuts have been prized objects for centuries. Before Europeans discovered the Seychelles, the seeds occasionally washed ashore in the Maldives and on the coasts of India, where their origin was unknown. They were believed to grow on a mythical tree at the bottom of the sea, and they commanded extraordinary prices as curiosities and supposed aphrodisiacs. That mystique persists. A single polished coco de mer nut can sell for hundreds of dollars as a souvenir, and the kernel is valued in parts of Asia for purported medicinal properties.
In the Vallée de Mai, almost all fallen nuts are collected by reserve management, around 800 per year in recent surveys, primarily to prevent poaching rather than as a deliberate harvest. Nuts sold legally as souvenirs require an official export permit from the Seychelles government. Despite these controls, illegal harvesting remains a serious problem. Poachers have been caught taking immature nuts directly from palm canopies, and a black market exists for coco de mer kernel, operated largely through a small number of exporters.3Forest Ecology and Management. Sustainable harvesting of coco de mer, Lodoicea maldivica, in the Vallée de Mai, Seychelles
The conservation math is unfavorable. When every fallen nut in the Vallée de Mai is collected and sold, none are left to germinate and replace aging adults. Researchers have raised concerns that current collection rates are unsustainable and that the population’s age structure, already skewed heavily toward juveniles, may not be replenishing the adult cohort fast enough. Habitat destruction in the early twentieth century, through burning and conversion to agriculture, reduced the species’ range before modern protections were established. Today the threats are different but no less acute: poaching, soil erosion from foot traffic in the reserve, and the slow-motion demographic squeeze of removing seeds from the reproductive cycle.
Growing Coco de Mer Outside the Seychelles
Botanical gardens around the world have attempted to cultivate Lodoicea maldivica, with mixed success. The palm is finicky. Germination alone can take one to two years, and the emerging seedling sends a long cotyledonary stalk underground before any leaf appears above the surface. Successful cultivation programs emphasize stable high temperature, high humidity, low light levels mimicking the forest understory, and, critically, leaving the germinating seed completely undisturbed. Even slight disturbance during the long germination phase can kill the embryo.4Journal of Botany. Observations on the Morphology, Pollination and Cultivation of Coco de Mer (Lodoicea maldivica)
Ex situ pollination has also been achieved, which is not straightforward for a dioecious species where male and female trees may flower on different schedules in cultivation. These efforts matter for conservation because maintaining a genetic backup population outside the Seychelles provides insurance against catastrophic loss in the wild. A single cyclone, wildfire, or disease event could devastate the concentrated natural populations. But cultivated coco de mer palms grow even more slowly than their wild counterparts, and no ex situ population comes anywhere close to replacing the wild stands.
Myths, Misconceptions, and the Suggestive Shape
It is impossible to discuss the coco de mer without addressing its shape. The bilobed seed bears a strong resemblance to a pair of human buttocks or a pelvis, and the male catkin is undeniably phallic. This has fueled centuries of folklore. In some traditions the trees were said to mate during storms, with anyone who witnessed the act dying. The resemblance also drove a long-standing association with fertility and aphrodisiac properties, which continues to fuel demand for the kernel in Asian traditional medicine markets.
There is no scientific evidence that coco de mer kernel has any medicinal or aphrodisiac effect. The market for it is driven entirely by cultural symbolism and traditional belief. Unfortunately, that cultural cachet is one of the species’ biggest threats. Illegal harvesting of immature nuts for their kernel bypasses the souvenir market entirely and strips seeds from the population before they have any chance of germinating. The irony is that a species struggling to reproduce is being poached partly because of mythological associations with fertility.
Another common misconception is that the coco de mer is a type of coconut. While both are palms and the coco de mer was historically called the “sea coconut” or “Maldive coconut” because its nuts washed up on distant shores, the two species are not closely related. The coco de mer belongs to the tribe Borasseae, a group of fan palms, while the common coconut (Cocos nucifera) is in a different tribe entirely. Their fruits evolved large size independently and for different ecological reasons. The coconut’s buoyant husk is a dispersal adaptation that carried it across the tropics; the coco de mer’s dense, sinking fruit is the opposite, a product of going nowhere at all.
What Fire and Fragmentation Do to a Slow-Growing Species
Much of the original coco de mer forest on Praslin was burned or cleared for plantations in the early twentieth century. What remains today in the Vallée de Mai is a fragment of a once more extensive palm forest. Outside the reserve, scattered coco de mer palms survive in degraded habitat mixed with introduced vegetation.
These fragmented populations face compounding problems. With male and female trees more widely spaced, pollen limitation becomes more severe, and fruit set drops. The proportion of fruits that develop abnormally rises in degraded habitat, suggesting that factors beyond just pollen distance are at play, possibly including nutrient stress or inbreeding effects.5PubMed Central. Tracing coco de mer’s reproductive history: Pollen and nutrient limitations reduce fecundity Fire remains a risk. In 1990, a fire in the Vallée de Mai destroyed several mature palms. Because each lost adult female represents decades of irreplaceable reproductive potential, even a small fire can set the population back by centuries in terms of seed output.
Climate change adds another layer of uncertainty. The Seychelles are low-lying and vulnerable to shifting rainfall patterns. The coco de mer’s nutrient-funneling leaf system depends on regular rainfall to wash intercepted material to the soil. Changes in the timing or intensity of rain could disrupt this mechanism, though no research has yet quantified how sensitive it is to altered precipitation. For a species with a 200-year lifespan and a 64-year wait to reproductive maturity, adapting to rapid environmental change is not really an option. Whatever conditions exist during a palm’s first decades of life essentially define its entire reproductive trajectory.