Avocado
From Wikipedia, the free encyclopedia
The
avocado (
Persea americana) is a
tree native to
Mexico and
Central America, classified in the
flowering plant family
Lauraceae along with
cinnamon,
camphor and
bay laurel.
Avocado or
alligator pear also refers to the
fruit,
botanically a large
berry that contains a single seed.
Avocados are commercially valuable and are cultivated in tropical and
Mediterranean climates throughout the world. They have a green-skinned,
fleshy body that may be pear-shaped, egg-shaped, or spherical.
Commercially, they ripen after harvesting. Trees are partially
self-pollinating and often are
propagated through
grafting to maintain a predictable quality and quantity of the fruit.
History
 |
Native "criollo" avocados,
the ancestral form of today's
domesticated varieties |
Persea americana, or the avocado, is believed to have originated in the state of
Puebla, Mexico,
though fossil evidence suggests that millions of years ago similar
species were much more widespread, occurring as far north as California
at a time when the climate of that region was more hospitable to them.
The native, undomesticated variety is known as a
criollo, and is small, with dark black skin, and contains a large seed. It likely
coevolved with extinct
megafauna.
The oldest evidence of avocado use was found in a cave located in
Coxcatlán, Puebla, Mexico, that dates to around 10,000 BC. The avocado
tree also has a long history of cultivation in Central and South
America; a water jar shaped like an avocado, dating to AD 900, was
discovered in the pre-
Incan city of
Chan Chan. The earliest known written account of the avocado in Europe is that of
Martín Fernández de Enciso (c.1470–c.1528) in 1518 or 1519 in his book,
Suma De Geographia Que Trata De Todas Las Partidas Y Provincias Del Mundo. The first written record in
English of the use of the word 'avocado' was by
Hans Sloane
in a 1696 index of Jamaican plants. The plant was introduced to
Indonesia in 1750, Brazil in 1809, South Africa and Australia in the
late 1800's, and the Levant in 1908.
Etymology
The word "avocado" comes from the Spanish
aguacate, which in turn comes from the
Nahuatl word
āhuacatl [aːˈwakat͡ɬ], which goes back to the proto-Aztecan
*pa:wa which also meant "avocado".
Sometimes the Nahuatl word was used with the meaning "testicle",
probably because of the likeness between the fruit and the bodypart.
In other central-American and Caribean Spanish-speaking countries it
is known by the Mexican name, while South-American Spanish-speaking
countries use a
Quechua-derived word,
Palta. In Portuguese it is
abacate. The fruit is sometimes called an avocado pear or alligator pear (due to its shape and the rough green skin of some
cultivars). The Nahuatl
ahuacatl can be compounded with other words, as in
ahuacamolli, meaning avocado soup or sauce, from which the
Spanish word
guacamole derives.
The modern English name is not etymologically related to the similar sounding Spanish word
abogado, meaning 'lawyer' (as in
advocate), but comes through an English rendering of the Spanish "
aguacate" as "
avogato".
The earliest known written use in English is attested from 1697 as
"Avogato Pear", a term which was later corrupted as "alligator pear". Because the word avogato sounded like "advocate" several languages reinterpreted it to have that meaning. French uses
Avocat, which also means
lawyer, and "advocate"-forms of the word appear in several Germanic languages, such as the German
Advogato-Birne, the old Danish
advokat-pære (today it is called "avocado") and the Dutch
advocaatpeer. It is known as "butter fruit" in parts of India. In eastern China it is known as
è lí (鳄梨, a direct translation of "alligator pear") or
huángyóu guǒ (黄油果, "butter fruit").
Cultivation
 |
Persea americana,
young avocado plant
(seedling), complete with
parted pit and roots |
| Food and agriculture |
| Country |
Quantity (t) 2011 |
World Rank |
| Mexico |
1,264,141 |
1 |
| Chile |
368,568 |
2 |
| Dominican Republic |
295,080 |
3 |
| Indonesia |
275,953 |
4 |
| United States of America |
238,544 |
5 |
| Colombia |
215,095 |
6 |
| Peru |
212,857 |
7 |
| Kenya |
201,478 |
8 |
| Brazil |
160,376 |
9 |
| Rwanda |
143,281 |
10 |
| China |
108,500 |
11 |
|
The tree grows to 20 m (66 ft), with alternately arranged
leaves 12 centimetres (4.7 in) – 25 centimetres (9.8 in) long. The
flowers are inconspicuous, greenish-yellow, 5 millimetres (0.2 in) – 10 millimetres (0.4 in) wide. The
pear-shaped
fruit is 7 centimetres (2.8 in) – 20 centimetres (7.9 in) long, weighs
between 100 grams (3.5 oz) – 1,000 grams (35 oz), and has a large
central
seed, 5 centimetres (2.0 in) – 6.4 centimetres (2.5 in) long.
The
subtropical
species needs a climate without frost and with little wind. High winds
reduce the humidity, dehydrate the flowers, and affect pollination. When
even a mild frost occurs, premature fruit drop may occur, although the
Hass cultivar
can tolerate temperatures down to −1 °C. The trees also need
well-aerated soils, ideally more than 1 m deep. Yield is reduced when
the irrigation water is highly
saline.
These soil and climate conditions are available only in a few areas of
the world, particularly in southern Spain, Portugal, Morocco, Crete, the
Levant, South Africa, Colombia, Peru, parts of central and northern
Chile, Vietnam, Indonesia, parts of southern India, Sri Lanka,
Australia, New Zealand, the Philippines, Malaysia, Central America, the
Caribbean, Mexico,
California,
Arizona,
Puerto Rico,
Texas,
Florida,
Hawaii, Ecuador and Rwanda. Each region has different types of cultivars.
Harvest and postharvest
Commercial orchards produce an average of seven tonnes per hectare
each year, with some orchards achieving 20 tonnes per hectare.
Biennial bearing
can be a problem, with heavy crops in one year being followed by poor
yields the next. The avocado tree does not tolerate freezing
temperatures, and can be grown only in subtropical or tropical climates.
There are several cold-hardy varieties planted in the region of
Gainesville, Florida, which survive temperatures as low as −6.5 °C
(20 °F) with only minor leaf damage.
The avocado is a
climacteric fruit (the
banana
is another), which means it matures on the tree, but ripens off the
tree. Avocados used in commerce are picked hard and green and kept in
coolers at 3.3 to 5.6 °C (37.9 to 42.1 °F) until they reach their final
destination. Avocados must be mature to ripen properly. Avocados that
fall off the tree ripen on the ground. Generally, the fruit is picked
once it reaches maturity; Mexican growers pick Hass-variety avocados
when they have more than 23% dry matter, and other producing countries
have similar standards. Once picked, avocados ripen in one to two weeks
(depending on the cultivar) at
room temperature (faster if stored with other fruits such as apples or bananas, because of the influence of
ethylene gas). Some
supermarkets sell pre-ripened avocados which have been treated with synthetic
ethylene to hasten ripening.
The use of an ethylene gas "ripening room", which is now an "industry
standard," was pioneered in the 1980s by farmer Gil Henry of
Escondido, California,
in response to footage from a hidden supermarket camera which showed
shoppers repeatedly squeezing hard, unripe avocados, putting them "back
in the bin," and moving on without making a purchase.
In some cases avocados can be left on the tree for several months,
which is an advantage to commercial growers who seek the greatest return
for their crop; but if the fruit remains unpicked for too long it falls
to the ground.
Breeding
 |
A seedless avocado,
or cuke, growing next to
two regular avocados |
The species is only partially able to
self-pollinate because of
dichogamy
in its flowering. This limitation, added to the long juvenile period,
makes the species difficult to breed. Most cultivars are propagated via
grafting, having originated from random seedling plants or minor
mutations derived from cultivars. Modern breeding programs tend to use isolation plots where the chances of cross-
pollination are reduced. That is the case for programs at the
University of California, Riverside, as well as the
Volcani Centre and the Instituto de Investigaciones Agropecuarias in
Chile.
The avocado is unusual in that the timing of the male and female
flower phases differs among cultivars. There are two flowering types,
"A" and "B". "A" cultivar flowers open as female on the morning of the
first day and close in late morning or early afternoon. Then they open
as male in the afternoon of the second day. "B" varieties open as female
on the afternoon of the first day, close in late afternoon and reopen
as male the following morning.
- "A" cultivars: Hass, Gwen, Lamb Hass, Pinkerton, Reed.
- "B" cultivars: Fuerte, Sharwil, Zutano, Bacon, Ettinger, Sir Prize, Walter Hole.
Certain cultivars, such as the Hass, have a tendency to bear well
only in alternate years. After a season with a low yield, due to factors
such as cold (which the avocado does not tolerate well), the trees tend
to produce abundantly the next season. In addition, due to
environmental circumstances during some years, seedless avocados may
appear on the trees.
Known in the avocado industry as "cukes", they are usually discarded commercially due to their small size.
Propagation and rootstocks
 |
| A young avocado sprout |
 |
Avocado is usually treated
with a special technique to
assist its sprouting process |
Avocados can be propagated by seed, taking roughly four to six years
to bear fruit, although in some cases seedlings can take 10 years to
come into bearing.
The offspring is unlikely to be identical to the parent cultivar in
fruit quality. Prime quality varieties are therefore propagated by
grafting to
rootstocks that are propagated by seed (seedling rootstocks) or by
layering
(clonal rootstocks). After about a year of growing in a greenhouse, the
young rootstocks are ready to be grafted. Terminal and lateral grafting
is normally used. The scion cultivar grows for another 6–12 months
before the tree is ready to be sold. Clonal rootstocks are selected for
tolerance of specific soil and disease conditions, such as poor soil
aeration or resistance to the soil-borne disease (root rot) caused by
Phytophthora.
Growing indoors
Usually, avocados are grown from pits indoors. This is often done by
removing the pit from a ripe, unrefrigerated avocado. The pit is then
stabbed with three or four toothpicks, about one third of the way up.
The pit is placed in a jar or vase containing tepid water. It should
split in four to six weeks and yield roots and a sprout. If there is no
change by this time, the avocado pit is discarded. Once the stem has
grown a few inches, it is placed in a pot with soil. It should be
watered every few days. Avocados have been known to grow large, so
owners must be ready to repot the plant several times.
Diseases
 |
| P. americana, avocado plant flowers |
Avocado trees are vulnerable to
bacterial,
viral,
fungal
and nutritional diseases (excesses and deficiencies of key minerals).
Disease can affect all parts of the plant, causing spotting, rotting,
cankers, pitting and discoloration.
Cultivation in California
The avocado was introduced from Mexico to California in the 19th century, and has become a successful
cash crop. About 59,000 acres (240 km
2) – some 95% of United States avocado production – is located in
Southern California, with 60% in
San Diego County.
Fallbrook, California, claims the title of "Avocado Capital of the World" (also claimed by the town of
Uruapan,
Michoacán,
México), and both Fallbrook and
Carpinteria, California, host annual avocado festivals.
Cultivation in Mexico
Mexico produces most of the world's avocado,
and avocado is one of the primary cultivars for export, the eighth
cultivar by production volume. In 2013 the total area dedicated to
avocado production was 168,155 hectares (415,520 acres), and the harvest
was of 1,109,814 tonnes. The states that produce the most are México, Morelos, Nayarit, Puebla, and Michoacan which accounts for 86% of the total.
In Michoacan the cultivation is complicated by the existence of drug
cartels that extort protection fees from cultivators. They are reported
to exact 2000 Mexican pesos per hectar from avocado farmers and an
additional 1 to 3 pesos per kilo of harvested fruit.
A cultivars
- Choquette
- A seedling from Miami, Florida, on the property of Remi Choquette. Now a favored commercial cultivar in south Florida.
- Hass
- While dozens of cultivars are grown, the Hass avocado is today the most common. It produces fruit year-round and accounts for 80% of cultivated avocados in the world. All Hass avocado trees are descended from a single "mother tree" raised by a mail carrier named Rudolph Hass, of La Habra Heights, California. Hass patented the productive tree in 1935. The "mother tree", of uncertain subspecies, died of root rot and was cut down in September, 2002.
Hass trees have medium-sized (150–250 g or 5.3–8.8 oz), ovate fruit
with a black, pebbled skin. The flesh has a nutty, rich flavor with 19% oil. A hybrid Guatemalan type can withstand temperatures to −1 °C (30 °F).
- Gwen
- A seedling bred from Hass x Thille in 1982, Gwen is higher yielding
and more dwarfing than Hass in California. The fruit has an oval shape,
slightly smaller than Hass (100–200 g or 3.5–7.1 oz), with a rich, nutty
flavor. The skin texture is more finely pebbled than Hass, and is dull
green when ripe. It is frost-hardy down to −1 °C (30 °F).
- Lula
- A seedling reportedly grown from a "Taft" avocado planted in Miami,
Florida, on the property of George Cellon, named after Cellon's wife,
Lula. It was likely a cross between Mexican and Guatemalan types. Lula
was recognized for its flavor and high oil content and propagated
commercially in Florida. It is also very commonly used as a rootstock
for nursery production. Hardy to −4 °C (25 °F)
- Pinkerton
- First grown on the Pinkerton Ranch in Saticoy, California,
in the early 1970s, Pinkerton is a seedling of Hass's Rincon. The large
fruit has a small seed, and its green skin deepens in color as it
ripens. The thick flesh has a smooth, creamy texture, pale green color,
good flavor and high oil content. It shows some cold tolerance, to −1 °C
(30 °F) and bears consistently heavy crops. A hybrid Guatemalan type,
it has excellent peeling characteristics.
- Reed
- Developed from a chance seedling found in 1948 by James S. Reed in
California, Reed has large, round, green fruit with a smooth texture and
dark, thick, glossy skin. Smooth and delicate, the flesh has a slightly
nutty flavor. The skin ripens green. A Guatemalan type, it is hardy to
−1 °C (30 °F). Tree size is about 5 by 4 meters (16.4 by 13.1 ft).
B cultivars
- Bacon
- Developed by a farmer, James Bacon, in 1954, Bacon has medium-sized
fruit with smooth, green skin with yellow-green, light tasting flesh.
When ripe, the skin remains green, but darkens slightly, and fruit
yields to gentle pressure. It is cold-hardy down to −5 °C (23 °F).
- Brogden
- Possibly a cross between Mexican and West Indian types, Brogden
originated as a seedling grown in Winter Haven, Florida on the property
of Tom W. Brogden. The variety was recognized for its cold-hardiness to
−5 °C (23 °F) and became commercially propagated as nursery-stock for
home growing. It is noted for its dark purple skin at maturity.
- Ettinger
- A Mexican/Guatemalan cross seedling of Fuerte, this cultivar
originated in Israel, and was put into production there in 1947. Mature
trees tolerate four hours at −6 °C (21 °F). The fruit has a smooth,
thin, green skin that does not peel easily. The flesh is very pale
green.
Avocado fruit (cv. 'Fuerte'); left: whole, right: in section
- Fuerte
- A Mexican/Guatemalan cross originating in Puebla,
the Fuerte earned its name, which means strong in Spanish, after it
withstood a severe frost in California in 1913. Hardy to −3 °C (27 °F),
it has medium-sized, pear-shaped fruit with a green, leathery, easy to
peel skin. The creamy flesh of mild and rich flavour has 18% oil. The
skin ripens green. Tree size is 6 by 4 meters (19.7 by 13.1 ft).
- Monroe
- A Guatemalan/West Indian cross that originated from a seedling grown
in Homestead, Florida on the property of J.J.L. Phillips, it was
patented in 1937 and became a major commercial cultivar due to its cold
hardiness and production qualities. The fruit is large, averaging over
two pounds (0.91 kg) in weight, has an elliptical shape, and green,
glossy skin. Hardy to −3 °C (27 °F).
- Sharwil
- Predominantly Guatemalan, with some Mexican race genes, Sharwil was selected in 1951 by Sir Frank Sharpe at Redland Bay, southern Queensland,
Australia. The name "Sharwil" is an amalgamation of Sharp and Wilson
(J.C. Wilson being the first propagator). Scions were sent from
Australia to Hawaii in 1966. A medium-sized fruit with rough green skin,
it closely resembles the Fuerte, but is slightly more oval in shape.
The fruit has greenish-yellow flesh with a rich, nutty flavor and high
oil content (20–24%), and a small seed. The skin is green when ripe. It
represents more than 57% of the commercial farming in Hawaii, and
represents up to 20% of all avocados grown in New South Wales,
Australia. It is a regular and moderate bearer with excellent quality
fruit, but is sensitive to frost. Disease and pest resistance are
superior to Fuerte.
- Zutano
- Originated by R.L. Ruitt in Fallbrook in 1926, this Mexican variety
is hardy to −4 °C (25 °F). The large, pear-shaped fruit has a shiny,
thin, yellow-green skin that peels moderately easily. The flesh is pale
green with fibers and has a light flavor.
Other cultivars
Other avocado cultivars include
Spinks.
The fruit of the cultivar Florida, grown mostly outside California, is
larger and rounder, with a smooth, medium-green skin, and a less-fatty,
firmer and fibrous flesh. These are occasionally marketed as low-calorie
avocados. Historically attested varieties (which may or may not survive
among
Horticulturists) include the Challenge, Dickinson, Kist, Queen, Rey, Royal, Sharpless, and Taft.
Avocado-related international trade issues
After the
North American Free Trade Agreement
(NAFTA) went into effect in 1994, Mexico tried exporting avocados to
the US. The US government resisted, claiming the trade would introduce
Tephritidae fruit flies that would destroy California's crops. The Mexican government responded by inviting
USDA
inspectors to Mexico, but the U.S. government declined, claiming fruit
fly inspection was not feasible. The Mexican government then proposed to
sell avocados only to the northeastern US in the winter (fruit flies
cannot withstand extreme cold). The US government balked, but gave in
when the Mexican government started erecting barriers to US
corn.
Today, avocados from Mexico are allowed throughout the US, because USDA inspectors in
Michoacán (where 90% of Hass avocados from Mexico are grown) inspected fruit in
Uruapan. Imports from Mexico in the 2005–2006 season exceeded 130,000
metric tons (143,300
short tons; 127,900
long tons).
In 2009, Peru joined Chile and Mexico as an exporter of avocados to the US.
In the US avocados are grown in California and Florida, where land,
labor and water are expensive. Avocado trees require frequent, deep
watering to bear optimally, particularly in spring, summer, and fall.
Due to increased Southern Californian water costs, they are now costly
to grow. California produces 90% of the United States' avocados.
As of 2013, Mexico leads international exports, with other
significant production in California, New Zealand, Peru and South
Africa.
Culinary uses
The fruit of horticultural cultivars has a markedly higher
fat content than most other fruit, mostly
monounsaturated fat,
and as such serves as an important staple in the diet of various groups
where access to other fatty foods (high-fat meats and fish, dairy
products, etc.) is limited.
A ripe avocado yields to gentle pressure when held in the palm of the hand and squeezed. The flesh is prone to
enzymatic browning; it turns brown quickly after exposure to air. To prevent this,
lime or
lemon juice can be added to avocados after they are peeled.
The fruit is not sweet, but rich, and distinctly yet subtly flavored,
and of smooth, almost creamy texture. It is used in both savory and
sweet dishes, though in many countries not for both. The avocado is very
popular in
vegetarian cuisine, as substitute for meats in sandwiches and salads because of its high
fat content.
Generally, avocado is served raw, though some cultivars, including
the common Hass, can be cooked for a short time without becoming bitter.
Caution should be used when cooking with untested cultivars; the flesh
of some avocados may be rendered inedible by heat. Prolonged cooking
induces this chemical reaction in all cultivars.
It is used as the base for the
Mexican dip known as
guacamole, as well as a spread on
corn tortillas or toast, served with spices.
In the
Philippines,
Brazil,
Indonesia,
Vietnam, and southern
India (especially the coastal
Kerala and
Karnataka region), avocados are frequently used for milkshakes and occasionally added to
ice cream and other desserts. In
Brazil,
Vietnam, the
Philippines and
Indonesia, a
dessert drink is made with sugar, milk or water, and pureed avocado.
Chocolate syrup is sometimes added. In
Morocco, there is a similar chilled avocado and milk drink, that is sweetened with
confectioner's sugar and hinted with
orange flower water.
In
Ethiopia, avocados are made into juice by mixing them with sugar and milk or water, usually served with
Vimto and a slice of lemon. It is also very common to serve layered multiple fruit juices in a glass (locally called
Spris) made of avocados, mangoes, bananas, guavas and papayas. Avocados are also used to make salads.
Avocados in savory dishes, often seen as exotic, are a relative novelty in
Portuguese-speaking countries, such as
Brazil,
where the traditional preparation is mashed with sugar and lime, and
eaten as a dessert or snack. This contrasts with Spanish-speaking
countries such as
Chile,
Mexico or
Argentina, where the opposite is true and sweet preparations are often unheard of.
In
Australia and
New Zealand, it is commonly served in sandwiches, sushi, on toast, or with chicken. In
Ghana,
it is often eaten alone in sliced bread as a sandwich. In Sri Lanka,
well ripened flesh, thoroughly mashed with sugar and milk, or treacle (a
syrup made from the nectar of a particular palm flower) was once a
popular dessert. In
Haiti it is often consumed with
cassava or regular bread for breakfast.
In Mexico and Central America, avocados are served mixed with white
rice, in soups, salads, or on the side of chicken and meat. In Peru,
they are consumed with
tequeños as mayonnaise, served as a side dish with
parrillas, used in salads and sandwiches, or as a whole dish when filled with tuna, shrimp, or chicken. In
Chile, it is used as a puree-like sauce with chicken,
hamburgers, and
hot dogs; and in slices for celery or
lettuce salads. The Chilean version of
Caesar salad contains large slices of mature avocado. In
Kenya
and Nigeria, the avocado is often eaten as a fruit, and is eaten alone,
or mixed with other fruits in a fruit salad, or as part of a vegetable
salad. In Iran, it is used as a rejuvenating facial cream.
Avocado slices are frequently added to hamburgers,
tortas,
hot dogs, and
carne asada. Avocado can be combined with eggs (in scrambled eggs, tortillas or omelettes), and is a key ingredient in
California rolls and other
makizushi ("maki", or rolled
sushi).
In southern Africa, Avocado Ritz is a common dish.
In the United Kingdom, the avocado became widely available in the 1960s when it was introduced by
Sainsbury's under the name 'avocado pear'.
Nutritional value
Avocados have diverse fats. For a typical avocado:
High avocado intake was shown in one preliminary study to lower blood
cholesterol levels. Specifically, after a seven-day diet rich in avocados, mild
hypercholesterolemia patients showed a 17% decrease in total serum cholesterol levels. These subjects also showed a 22% decrease in both
LDL (harmful cholesterol) and
triglyceride levels and 11% increase in
HDL (helpful cholesterol) levels. A 2013
epidemiological
report funded by the Hass Avocado Board showed that American avocado
consumers had better overall diet quality, nutrient levels, and reduced
risk of
metabolic syndrome.
Extracts of avocado have been studied in laboratory research to assess potential for lowering risk of
diabetes mellitus.
A Japanese team synthesised the four
chiral components of avocado, and identified (2R, 4R)-16-heptadecene-1, 2, 4-triol as a potential
antibacterial component. Due to a combination of specific
aliphatic acetogenins, avocado is under preliminary research for potential anti-cancer activity.
As a houseplant
20cm avocado houseplant leaf
While not particularly popular, the avocado tree can be grown domestically and used as a (decorative)
houseplant.
The pit germinates in normal soil conditions or partially submerged in a
small glass (or container) of water. In the latter method, the pit
sprouts in four to six weeks, at which time it is planted in standard
houseplant potting soil. The plant normally grows large enough to be
prunable; however, it does not bear fruit unless it has ample sunlight.
Home gardeners can
graft
a branch from a fruit-bearing plant to speed maturity, which typically
takes four to six years to bear fruit. To obtain fresh avocado produce,
however, more than one tree must be cultivated for cross-pollination.
Allergies
Some people have
allergic reactions
to avocado. There are two main forms of allergy: those with a
tree-pollen allergy develop local symptoms in the mouth and throat
shortly after eating avocado; the second, known as latex-fruit syndrome, is related to
latex allergy and symptoms include generalised urticaria, abdominal pain, and vomiting and can sometimes be life-threatening.
Toxicity to animals
Avocado leaves,
bark, skin, or
pit are documented to be harmful to animals; cats, dogs, cattle, goats, rabbits,
rats, guinea pigs, birds, fish, and horses can be severely harmed or even killed when they consume them. The avocado fruit is poisonous to some birds, and the
American Society for the Prevention of Cruelty to Animals (ASPCA) lists it as toxic to many animals including cats, dogs, and horses.
Avocado leaves contain a toxic fatty acid derivative,
persin, which in sufficient quantity can cause
colic in horses and, without veterinary treatment, death.
The symptoms include gastrointestinal irritation, vomiting, diarrhoea,
respiratory distress, congestion, fluid accumulation around the tissues
of the heart, and even death. Birds also seem to be particularly
sensitive to this toxic compound. A line of premium dog and cat food,
AvoDerm, uses oils and meal made from avocado meat as main ingredients.
The manufacturer says the avocado's leaves and pit are the source of
toxicity, and only in the Guatemalan variety of avocados, and the fruit
is often eaten by orchard dogs as well as wildlife such as bears and
coyotes.
Co-evolution
In 1982, the evolutionary biologist
Daniel H. Janzen suggested that the avocado may be an example of an '
evolutionary anachronism', a fruit adapted for
ecological relationship with now-
extinct large mammals (such as giant
ground sloths or
gomphotheres). Most large fleshy fruits serve the function of
seed dispersal,
accomplished by their consumption by large animals. There are some
reasons to think that the fruit, with its mildly toxic pit, may have
co-evolved with
Pleistocene megafauna
to be swallowed whole and excreted in their dung, ready to sprout. No
extant native animal is large enough to effectively disperse avocado
seeds in this fashion.
Lemon Tuna Avocado Snack
Spicy Avocado Pizza
