Why No Bananas on a Boat?

The Origins of the Superstition

Ask any offshore captain why bananas aren't welcome on deck and you'll get a knowing look before the explanation. It's one of fishing's oldest, stickiest superstitions — and unlike most sea lore, this one has a documented practical backstory, not just folklore.

In the 18th and 19th centuries, as the banana trade between Latin America and ports in the U.S. and Europe took off, whole stalks were loaded into cargo holds green, hands and all. Straight off tropical plantations, those stalks sometimes carried unwelcome stowaways — spiders and snakes tucked among the leaves — and crew handling the cargo occasionally got bitten.

Lethal Spriders & Venomous Stowaways

Harvesting bananas in the tropical plantations of Central and South America involved cutting down massive, dense bunches of fruit. These humid, overlapping banana bunches were the perfect natural shelter for some of the world's most dangerous creatures.

Chief among these was the infamous **Brazilian Wandering Spider** (species *Phoneutria*), colloquially known as the "banana spider." These large, aggressive, and highly venomous arachnids would nest deep within the fruit bunches. When the bananas were loaded into confined cargo holds, the spiders came along for the ride.

Two Competing Theories & Evidence

Historians generally point to two intertwined explanations for how bananas got blamed — one about the cargo, one about the ships that carried it.

Methane Accumulation & Spontaneous Combustion

When vast quantities of bananas decomposed rapidly in sealed, unventilated lower holds, they didn't just rot—they fermented. Methane is lighter than air, highly flammable, and can act as an asphyxiant in high concentrations. On wooden ships lit entirely by tallow candles and oil lanterns, a build-up of explosive methane gas was a ticking time bomb. Ships would spontaneously catch fire or experience explosive hull failures in the middle of the ocean, sinking without leaving a single survivor to explain what happened.