BATS AND AVOCADOS

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My mother was born on a Caribbean island in 1902. She was raised on fish, cassava, custard apples, sweet sops, sour sops and pears. We soon learned mother wasn't talking about sweet dessert pears. She was talking about savoury, soft, buttery pears; avocados.

Avocados grew first in Mexico. In l685 William Dampier, an English buccaneer and naturalist, ate avocados while waiting to plunder a Spanish ship in the Pearl Islands, Panama Bay, western Central America. The English-reading world met avocados for the first time in Dampier's popular writings. "(The fruit is) as big as a large lemon. It is of a green colour, till it is ripe, and then it is a little yellowish. They are seldom fit to eat till they have been gathered two or three days; then they become soft, and the skin or rind will peel off. The substance inside is green, or a little yellowish, and as soft as butter." (Preston & Preston)

Today the avocado prospers in tropical climates throughout the world.

Scientific literature identifies two New World tropical bats as wild avocado seed planters, the Jamaican fruit bat and the great fruit bat; Artibeus jamaicensis and Artibeus lituratus.

Great fruit bat (Artibeus lituratus)
Photograph by David Liebman, Lubee Bat Conservancy

Goodwin and Greenhall identified the remains of avocado, Persea americana, on the floor of roosting caves used by the Jamaican fruit bat and the great fruit bat on Trinidad.

Large wild avocado, approximate size, 64x50 mm (2.5x2 in)

Some wild avocado species are small, measuring about 35 mm(1.3 inches)in length and 20 mm (.8 inches) in diameter. Carrying a wild avocado of those dimensions from the parent tree is not a problem for the Jamaican fruit bat and the great fruit bat. Merlin Tuttle captured a Jamaican fruit bat which was transporting a fig which measured 30 mm (1.18 inches) in diameter. Gardner mist-netted the same bat species carrying a guava that was 64 mm long (2.5 inches) and 50 mm (2 inches) in diameter, about the size of the wild avocado pictured above.

 

Jamaican fruit bat (Artibeus jamaicensis)
Photograph by Pam Thomas, Lubee Bat Conservancy

Remains of avocados dating to 7000 B.C. have been discovered in Mexico. By 900-200 B.C. there is evidence that avocado plants were being selected for yield of larger fruits, a process that required patience and took many years to accomplish. Avocado seedlings do not bear fruit for 7 years so the hopeful farmer would have a long wait to see whether his effort to design an avocado plant with larger fruit was successful.

Comparison of flesh to seed ratio of wild and cultivated avocados.
(Not to scale)

Over 700 varieties of avocados have been cultivated from the original species of wild Mexican avocados. This process was particularly active during the early 1900's. Perhaps strong commercial interest in the cultivation of avocados was based on the alleged aphrodisiac properties of avocados. Avocados appear in pairs on the tree and resemble testicles in shape, an observation borne out by the tree's Aztec name, ahuacacuahatl, which translates as testicle tree.

For whatever reason, avocado cultivars, numbering over 700, were created.

Many of those species have been abandoned because they:

• were too big, too small, too oily, not oily enough, unpopularly coloured (purple), were too thick skinned, too long in the neck, were poor keepers, had an overlarge seed, had too many fibres;

or the tree:

• shed too many fruit, was too frail, overbloomed, overbeared, died back, was prone to disease, was too sensitive to cold, too tall, too slender, or bore fruit too late.

A California postman, Rudolph Hass, planted an avocado seed in 1926, and the progeny of that tree still produce one of the world's most popular and name-familiar avocados. Reputedly, the parent tree is standing in La Habra Heights, California.

To satisfy today's shoppers, an avocado must meet several requirements besides being delicious to eat;

Size: Small to medium in size. ('Pollock' 1901, superior quality but weighed up to 5 pounds, therefore too big)

Skin: Smooth, thin, easily removed. Bumpy skin is acceptable if easily removed.

Flesh: Fibre free.

Seed: Not too big. The delicate seed skin must stay on the seed and not unite with the flesh of the avocado cavity.

Quetzal with wild avocado

Less demanding than humans are the animals who relish wild avocados and who are responsible for the survival of the wild trees, the repositories of valuable genetic information.

Among those avocado-eating animals, including bats, is the quetzal, sacred bird of the Aztecs and national bird of Guatemala. The quetzal, worshiped by Aztecs and Mayas as the god of the air, is a vanishing species, the victim of habitat loss, a habitat which provided its diet, small fruit, including the wild avocado. The quetzal swallows an entire wild avocado. The action of the bird's crop removes the modest amount of fruit flesh for further absorption. The quetzal then disgorges the seed.

Avocado medicine:

Combat pyorrhea by chewing avocado leaves. Sooth wounds and accelerate healing by applying an avocado leaf poultice. Bind an aching head with a warm wrap of avocado leaves. Take avocado leaf tonic to cure a stomach ache and still a cough. Reduce high blood pressure, halt diarrhea and relieve a sore throat with avocado leaf juice.

The human body's absorption of cholesterol is hampered by beta-siterol. Avocados contain more beta-siterol than any known fruit. Avocados contain four times as much beta-siterol as oranges, which are considered a rich source.

Avocado wood:

Avocado tree wood can be turned to make sculptures, jewel boxes and vases. An avocado tree branch can be carved and converted into a stylish walking stick. Effective wands for metaphysical purposes can be made from avocado tree wood. Historically, in Mesoamerica, the wood of the tree was used to make tools and small boats.

Avocado ink, insecticide, cosmetics and honey:

Documents written during the Spanish Conquest with avocado seed ink still survive in museums today. A milky exudate from the seed is indelible and turns dark reddish brown.

Bee-collected nectar from avocado flowers yields a heavy, deeply coloured honey.

Crop-eating organisms can be controlled by an oil from waste avocados.

Oil from marketable avocados is an ingredient of hundreds of cosmetics which enhance hair and skin.

Avocado employment:

The avocado plant provides thousands of jobs for human beings. In 1991, 45,000 people in the Mexican state of Micheacan worked in the avocado industry. Avocados are the area's most important crop.

Mexico leads the world in commercial avocado production with over 260,000 tons. Thousands of people in the Dominican Republic, California and Florida, Brazil, Israel and South Africa find work in the avocado industry, ensuring that the world is provided with an additional 400 tons of avocados.

References:

Attenborough, David, 1995, The Private Life of Plants, BBC Books

Bates, Marston, 1971, The Land and Wild-life of South America, Time-Life Books.

Hedrick, U.P., editor, Sturtevant's Edible Plants of the World, Dover Publications, 1972 (First published in 1919)

Heywood, V.H., editor, 1979. Flowering Plants of the World, Oxford University Press

Morton, Julia, Fruits of Warm Climates, 1987; http://www.hort.purdue.edu/newcrop/morton

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

Preston, Diana & Preston, Michael, 2005, A Pirate of Exquisite Mind; The Life of William Dampier; Explorer, Naturalist and Buccaneer, Corgi Books.

Root, Waverley 1980. Food, Simon and Schuster, New York.

Usher, George, A Dictionary of Plants Used by Man, Constable and Company Ltd, 1974

Thank you to the Lubee Bat Conservancy for permission to use photographs by David Liebman and Pam Thomas of Artibeus lituratus and Aritbeus jamaicensis.

http://www.lubee.org

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