Of the more than 80,000 plant species that some scientists estimate the forests of the Amazon basin may be home to, perhaps one of the most unusual is Socratea exorrhiza, better known in Spanish as the “palmera caminante”, or in English as the “walking palm”.
In the tropical forests of South and Central America, trees and other plants must compete with the neighboring species that crowd in on them for two things essential to plant life: nutrient providing soil or biomass, and sunlight.
As its name suggests, the walking palm, also known as the “cashapona”, has evolved a remarkable method for ensuring it enjoys a competitive advantage in the struggle for life in the rainforest.
The trunk of this slender 10- to 25-meter-high palm tree emerges from a cone-like set of aerial roots, visible above the ground. Acting like stilts, these roots keep the trunk, the diameter of which measures up to 20 centimeters, raised above the forest floor. The first scientists to study this remarkable palm concluded that its aerial roots functioned in a similar way to the buttress roots of much larger species, such as the mighty kapok, which is held upright by the roots it throws out to the sides, and which resemble the flying buttresses of 12th century Europe’s gothic cathedrals. Without such a system, the shallow roots of enormous trees like the kapok would leave them extremely unstable in the typically nutrient poor soils of the Amazon basin.
However, scientists soon began to realize that Socratea exorrhiza employs its aerial roots not as a way of stabilizing its slender structure, but as a method for “moving on” when the palm becomes shaded by other, larger trees, and the soil is stripped of its meager nutrients. By producing new aerial roots, the walking palm is able to very slowly relocate to another part of the forest floor with better conditions for life; specifically, undisturbed nutrient-rich soil and improved access to life-giving sunlight. Some reports have claimed that this palm may be able to move up to twenty meters from its original position, in a process that can take up to two years. As the soil upon which the palm rests is degraded, it grows new long roots into undisturbed ground, very gradually bending its entire structure towards those new roots, until the older roots are lifted from the ground.
Traditionally, the spiny roots of the cashapona walking palm have been used by indigenous Amazonian peoples to grate plant-based foods, and its straight and slender main trunk has been used in the construction of huts, or for making spears. The yellow fruits of the walking palm are edible, and traditionally its roots have also been used by forest dwelling peoples in their medicinal practices, as both an aphrodisiac and in the treatment of hepatitis.