BATS, BALSA, KON TIKI and the MOSQUITO AEROPLANE

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In l947 Thor Heyerdahl, a Norwegian, sailed with five companions from Peru to the South Sea Islands, a voyage of 5000 miles. For l0l exciting days the six men lived on a raft built on 9 balsa logs.

In the final paragraph of Thor Heyerdahl's account of this epic voyage on Kon Tiki, he wrote:

" . . . the six of us on deck, standing beside our nine dear balsa logs, were grateful to be all alive." (1)

At that time Thor Heyerdahl probably did not know that he could have widened his gratitude to include the bats which pollinate the big white flowers of the balsa trees growing in the jungles of Ecuador. Those bat-pollinated flowers produced the fertile seeds which sprouted and grew to become the 9 "dear" logs of the Kon Tiki.

At least five species of New World Tropics bats are known to pollinate the flowers of the balsa tree;the Pale spear-nosed bat, Pallas's spear-nosed bat, the Jamaican fruit bat, big fruit bat and Seba's short-tailed bat.(2)

Big fruit bat (Artibeus lituratus)
Photograph: David Liebman, Lubee Bat Conservancy

Thor Heyerdahl could have also thanked the bats that helped to pollinate the mangrove trees from which two essential parts of his craft were fashioned; the l5 foot steering oar and the 29 foot high masts. He could have thanked the bats that helped to pollinate and plant the banana plants from which the walls and roof of the cabin were fashioned and from which the matting of the foredeck was woven.

In May l970 Vital Alsar, a Spaniard, and four companions, one of them a seaworthy kitten, sailed from Ecuador on La Balsa, a 7-log balsa raft with mangrove masts. They passed l000 miles north of Thor Heyerdahl's final destination and threaded their way through reef-strewn seas to reach Mooloolaba on the east coast of Australia, a trip of 8600 miles. Three years later Alsar completed a similar voyage, this time with a flotilla of three balsa log rafts. Again, bat-pollinated balsa trees proved their value as the integral component of long distance sea-going rafts. (3) Between 1947 and 1995 an additional ten manned balsa rafts departing from Peru and Ecuador have reached Polynesian islands. (4)

WAS THOR HEYERDAHL THE FIRST PERSON TO MAKE A SEAGOING RAFT OF BALSA LOGS?

No. The Huancavilca Indians of western South America had been sailing on sea-going balsa log rafts for hundreds of years. The rafts used by Heyerdahl and Alsar were replicas of those ancient rafts. Their journeys were designed to prove that colonizing trips could have been made by South American Indians to the South Sea Islands.

When exploring the west coast of America in l526, the Spanish explorer, Francisco Pizarro, met Peruvian balsa rafts under sail carrying as many as fifty people and two horses. Those rafts were as large as some of the Spanish ships. The balsa rafts were 80 or 90 feet long.(5)

The Santa Maria, upon which Columbus sailed on his first voyage to the New World in 1492, was about 115 feet long. The Pinta was less than 60 feet long, and the Nina was smaller than the Pinta.(6)

Indians in Ecuador still make rafts from balsa logs for local travel. You can go on an ecotourism project holiday in Ecuador where you will travel by balsa log rafts.(7)

WHY ARE BALSA LOGS SO USEFUL FOR MAKING SEA-GOING RAFTS?

Because the wood is strong, light and buoyant. Being "buoyant", it is able to float lightly on water. In Ecuador the tree is called "boya". The world "balsa" is a Spanish word meaning raft.

IT SOUNDS AS THOUGH BALSA TREES HAVE AN ANCIENT AND INTERESTING HISTORY.

They have a recent interesting history as well. During World War II an innovative, multi-purpose, light, fast airplane, the Dehavilland Mosquito, was designed and built in Britain.

The fuselage was a wood sandwich. Balsa wood was the filling and birch plywood was the bread.(8)

Balsa wood was used so widely during World War II that when Thor Heyerdahl went to Ecuador he could find no large balsa trees on the coast. They had all been felled to build Mosquito airplanes and insulate Liberty Ships during the war.(8) He had to fly inland and make an arduous journey overland to find satisfactory logs which were then rafted and floated to the coast by rivers.(1)

ARE THERE MANY USES FOR BALSA WOOD TODAY?

As an example, the company, Alcan Baltek Corporation, has developed, over a 70 year period, an impressive array of commercial balsa wood uses. In the sixty years after the Mosquito aeroplane-Liberty Ship era, balsa wood is still used in airplanes, ships and boats. Tankers that transport compressed gas are insulated with balsa wood. Many structures in large, fast ships are made of balsa sandwiched in reinforced plastic. That combination of strengths can absorb the battering of waves. (10)

Reinforced plastic sandwich panels with a balsa core is also used in a great variety of other applications in the chemical industry, in food processing and water purification. They are a component of air cargo pallets, windmill blades, shipping containers, bathtubs, shower stalls and railcars, trucks and buses. And, of course, balsa is still the wood of choice for making model airplanes and gliders. (10)

DO BALSA TREES GROW ALL OVER THE WORLD?

No. Ninety-eight percent of the balsa wood sold throughout the world is from Ecuador. Some balsa wood is grown in Central America and New Guinea. Balsa wood is exported from these countries to more than 45 countries in the world.(11)

ARE THERE COMMERCIAL BALSA TREE PLANTATIONS?

Yes. For example, to provide balsa wood for its many innovative applications, Alcan Baltek Corporation maintains balsa tree plantations in Ecuador which provide jobs for over900 people.(10)

Wild trees are also harvested from the forest. That is a difficult task because balsa trees are scattered. There may be only one or two trees per acre. Two men working with an ox team may only be able to get two balsa logs cut and transported to a river in a day. At the rivers balsa logs are rafted together and floated out for many miles to coastal settlements.(1)

BAT-POLLINATED BALSA TREES DEFINTELY GIVE PEOPLE EMPLOYMENT.

Yes, there are balsa-related jobs and incomes for human beings, thanks in part to the pollinating bats.

Bats may not be the only mammal that pollinates the flowers of the balsa tree. White-nosed coatis, a raccoon relative, have been seen climbing in balsa trees and putting their flexible noses into the balsa tree flowers to savour the sweet nectar and emerging with pollen-coated noses. The coatis are able to do this without damaging the flowers which helps to ensure a fertile seed set.(12)

References:

(1)Heyerdahl, Thor, The Kon-Tiki Expedition, 1950

(2)New York Botanical Gardens Bat/Plant Databases http://www.nybg.org/botany/tlobova/mori/batsplants/database/dbase_main.htm

(3)Alsar, Vital, La Balsa, The Longest Raft Voyage in History, Hodder and Stoughton, London, 1971

(4) Heyerdahl, Thor, Sandweiss, D.H., Narvaez, A., Pyramids of Tucume; The Quest for Peru's Forgotten City, Thames and Hudson, 1995.

(5)Thor Heyerdahl, Extracts from Lectures, Sea Routes to Polynesia, The Balsa Raft in Aboriginal Navigation of Peru and Ecuador, Bradshaw Foundation; http://www.bradshawfoundation.com/thor

(6)Castlereagh, Duncan, The Great Age of Exploration, The Reader's Digest Association Limited, London, 1971, page 87

(7)Piedra Blanca Community Ecotourism Project, Ecuador Rafting Tours & Adventure, Live Travel Guides:South American Travel Links; http://www.livetravelguides.com/useful-links/south-american-travel-links

(8)Lewington, Anna 1990. Plants for People, Natural History Museum Publication, page 181

(9)Cavanaugh, Bill, Ode to Balsa, Baltimore Area Soaring Society, BASS Newsletter, March 1995; http://www.soarmd.org/BassNews/balsa.html

(10)Alcan Baltek Corporation - About Baltek; http://www.baltek.com/aboutbaltek/abaltek.html

(11)The Best of Ecuador,Ecuador exports > Wood; http://www.thebestofecuador.com/wood.htm

(12)Mora, Jose M., Mendez, Vivian, Gomez, Luis, White-nosed coati, Nasua narica (Carnivora:Procyonidae)as a potential pollinator of Ochroma pyramidale (Bombacaceae), Revista de Biologia Tropical, v. 47, n. 4, ISSN 0034-7744, 1999; http://www.scielo.sa.cr/scielo/php?pid=S0034-77441999000400008&script=sci_arttext&tlng=en

Text and illustrations by Mary Louise Alley-Crosby who thanks Dr. Merlin D. Tuttle, Founder and President, Bat Conservation International, Austin, Texas, for permission to use his photograph of Seba's short-tailed bat as illustrative source material and Lubee Bat Conservancy for permission to use David Liebman's photograph of Artibeus lituratus.

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Updated 16 May 2006