If you've seen the 2000 movie "Cast Away," you probably remember the scene in which Tom Hanks' character, who survived a plane crash and found refuge on a desert island, struggles to crack open coconuts before finally figuring out how to tap into one and drink from it.
That moment is fairly commonplace desert-island-survival-movie stuff, but just how reality-based is the idea of actually living off coconuts if you were stranded and needed food and water? Well, it turns out that, in such a situation, a coconut palm tree actually could be your best hope for survival.
There are numerous species of palm trees that produce edible fruits, ranging from date palms, which have been cultivated since ancient times in the Middle East, and the snake palm, which produces a reddish-brown fruit whose pulp has a sweet, acidic taste, to the peach palm found in Central and South America, whose fruit must be cooked for several hours before it can be eaten. But if you're looking for the palm species that would produce the most nutritious fruit and would be likely to be found on a Pacific island, the fruit that Tom Hanks (and Wilson?) could have survived on, the choice narrows down.
"My main answer to you is COCONUTS!!" says Sara Tekula, director of programs at the Merwin Conservancy, a 19-acre (7.7-hectare) sanctuary for rare palms that was hand-planted by the late poet W.S. Merwin and features over 400 species of palm from around the world. "Coconuts, coconuts, coconuts."
The coconut palm tree (Cocos nucifera) is native to tropical islands in the western Pacific Ocean, according to the Missouri Botanical Garden. They're tall trees, growing as tall as 100 feet (30 meters), and have a trunk with a branchless, light gray trunk that's swollen at the base and topped by a crown of arching green fronds that stretch as long as 20 feet (6 meters). It has fragrant yellow flowers, which appear in clusters, and of course, coconuts, which technically are a fruit rather than a nut, and grow to up to 14 inches (36 centimeters) long.
Tekula explains in an email that although coconut palms aren't native to the Hawaiian islands, they are commonly found growing there and elsewhere in the Pacific. Atlas Obscura reports that nearly 40 percent of the world's islands exist within the climate zone that's hospitable to coconut trees.
Coconut Palm, the Tree of Life
"They are referred to as 'the tree of life' in the Philippines, 'the tree with a thousand uses' in Malaysia, and 'the tree which provides all the necessities of life' in Sanskrit," Tekula continues. "Without a doubt, if you were stranded on an island, you'd want a mature coconut tree to be there with you! There are stories of island and coastal people in the tropics surviving months of drought with coconut palms providing the only drinking water available."
Indeed, according to this 2004 Guardian article, three children who survived the sinking of their parents' boat in Papua New Guinea and swam to a small island managed to live for several day on a diet of coconuts, plums and oysters, until they were finally rescued.
"In Hawaii, coconut palms are known as 'niu' and are considered a very important food source," Tekula continues. "And while they are not native to this place, they are one of the celebrated "canoe plants" — valued cargo on the sailing canoes of the original Polynesian voyagers to Hawai`i. Some of the ancestors of the trees currently found in Hawai'i also floated ashore, alive for up to 4 months at sea, still able to germinate. They are the symbol of resilience! They are celebrated here so much so that traditionally, a coconut palm is planted at the birth time of a child born here in Hawaii. Niu is the kinolau (physical embodiment) of a Hawaiian god."
If you're sufficiently agile and adventurous, you can climb up the coconut tree to pick coconuts; otherwise, you can wait for them to ripen and fall to the ground. The fruit has a wooden shell surrounded by a fibrous husk, but inside is the stuff that a person wants — the coconut meat, which can be eaten raw or cooked, and the drinkable liquid, called coconut water, according to the Missouri Botanical Garden.
"The nutritional qualities of a coconut — its meat and its water/juice — are nothing short of miraculous," Tekula explains. "The meat is high in healthy fats, which are very important for survival, and the juice is filled with minerals/micronutrients like potassium, manganese, copper, iron, selenium, zinc and can keep your electrolytes balanced and blood levels healthy."
If you're thinking about bringing a coconut in your cruise ship luggage to plant in case you're somehow marooned, you may be disappointed to learn that it takes seven to eight years for a tree to grow to the point where it can produce coconuts, according to Takula. On the other hand, if you find a coconut tree that's already been growing for a while in high-quality soil, it can yield between 30 and 75 fruits per year, and keep doing that for several decades, she says.
Besides providing food, coconut trees' leaves can be used to make the thatched roof of a hut, and the shells can be burned as fuel. "A few of these trees will provide you with every possible thing you require," the naturalist Percy Roycroft Lowe wrote in 1911. As this 2017 BBC Travel article notes, coconut oil also has antibacterial properties.
But while coconuts are highly nutritious, depending on them as your lone food source for long periods might not be ideal. There's the cautionary tale of August Engelhardt, a German nudist and coconut devotee who lived on the island of Kabakon in which is now Papua, New Guinea, from 1902 to 1919 and subsisted entirely upon a diet of coconuts. After seven years of that extreme diet, he was so severely malnourished that his bodyweight was just 66 pounds. He reportedly was found dead on the beach, according to this National Public Radio story. Engelhardt became a character in Swiss writer Christian Knacht's well-regarded 2012 novel, "Imperium: A Fiction of the South Seas."
“Coconuts are a complete fat source and are a good source of protein and carbohydrates as well if you eat the ball in the middle of a sprouting nut," explains Tom Williams, whose company, Desert Island Survival, offers survival training courses on uninhabited islands in the Pacific. "However, they are severely lacking in Vitamins A, K, B6 and B12, as well as calcium. Deficiencies in these vitamins can cause pernicious or microcytic anemia, loss of ability to fight infections, and increased bruising/bleeding."
"As far as water, if you just drink the green coconuts, you can survive on this as a water source," Williams writes in an email. "If you drink just the mature nuts, the high oil and mineral content will lead to diarrhea and ultimately dehydration."
Williams says that getting into a coconut isn’t difficult for someone with a machete or a knife. But like Tom Hanks in the movie, an actual castaway probably isn’t going to have such tools. "In this case, juvenile green nuts can easily be split open hitting them on jagged rocks," Williams says. "Older mature nuts with more meat develop a very strong protective husk to prepare them for voyages across the ocean, and this is extremely hard to get into. The best method without a knife is to make a spike from a hardwood. This is not a simple process without a knife but can be achieved by fire — also further hardening the spike — and then sharpening the point on rocks. You can then use the point to pry open the husk."