By Alicia Colson
Someone said ‘avocado toast’ is cool. The ‘in’ food eaten by the ‘in’ crowd in ‘hip’ places in the fashionable parts of town. ’ Avocado toast’ is simply avocado which has been sliced or smashed on top of a piece of toast. Some people even eat it with honey drizzled on top. Whether you think this is cool is your personal preference. That may well depend on where you live. The fruit of a tree, avocados are more often eaten in salads, the main ingredient in guacamole (try our mango guac here), or in ice-cream! Some people love to eat their flesh with a spoon, while the hole (where the pip was situated) is filled with soy sauce, mayonnaise or olive oil and balsamic vinegar. But where did they come from and how old are they?
Let’s start with the first question: What’s an avocado?
Well, let’s start from with a simple search on the web. It emerges that the avocado (Persea Americana) is a member of a plant family Lauraceae, from the Americas. It is one of the oldest known flowering plant families.  It turns out to be a fruit, not a vegetable, a large berry containing a single seed. Grown in tropical climates, avocados can be spherical, pear-shaped, or even egg-shaped. They s grow on trees, not shrubs. Unlike other berries, such as coffee or cacao, they’re often recommended as a “superfood”; one that’s good for your heart. They are rich with vitamins, mineral and other nutrients. Some even claim that “one-third of a medium avocado (50 g) has 80 calories and contributes nearly 20 vitamins and minerals, making it a great nutrient-dense food choice.” 
So how old is the avocado?
You would never guess that the avocado existed during the Cenozoic Era (two million years ago). Apparently the avocado was one of the plants eaten by the large animals who lived in this period called Megafauna. Megafauna are very large land creatures (bigger than a human) such as the Gomphothere (large elephant-like creatures with four sets of tusks), Megatherium (giant ground sloths which weighed four tons), Toxodon (similar to rhinoceros), and Glyptodon (a mega-armadillo). Some speculate that because these creatures swallowed the avocado whole, they benefited from a fatty healthy meal, expelling the plant’s seeds, amid other wastes, as dung which supported its early stages of growth. But the majority of the world’s megafauna vanished about 13,000 years ago during the midst of extinctions in the Pleistocene Era.The sub-continent of South America was the worst affected as it lost 83% of its large mammals while North America lost 68%. So the avocado eaters, the mammoths, mastodons, sabre-tooth cats and woolly rhinos died out. So who dispersed the seeds once the principal consumers died? It’s likely that with the advent of humans, the way in which avocado trees were dispersed simply changed.
Researchers (archaeologists, archaeo-botanists and botanists) have discovered that avocados were first domesticated in Mesoamerica  and the types of avocados simply reflect differences in the ecology. It appears that avocado trees were probably one of the first trees to be domesticated using planting and grafting in the neotropics of Mesoamerica, where they played a vital role in the development of the human population. Slowly but surely domesticated the avocado played a key role in preserving the rich biodiversity of the plants and trees in the Neotropics. 
What happens when the avocado was domesticated?
Researchers think that the most productive way of documenting the presence of domesticated plants is to map and track the ways in which parts of a plant physically change shape. These can be identified as the morphology of the plan is preserved in the archaeological record. It is suspected that the morphological changes in the shape of the berry (the avocado itself) are strongly connected to changes in human settlement. For example the seeds changed shape: the wild populations of avocados in Southern Mexico or adjacent parts of Mesoamerica have seeds which nearly spherical. As the plants were domesticated, the seeds and their protective cover (the skin) slowly become longer.A study of plant and animals remains at 11 archaeological sites in the Moche Valley, Peru indicates that the avocados were cultivated before about 2500 B.C. This finding is derived from n evidence of the trees having been moved by humans into South America by this time. Evidence from an archaeological site called Puebla, in Tehuacan valley, dated 8,000-7,000 B.C indicates that the avocado was possibly domesticated since 6,400 B.C.Researchers think that more research needs to be undertaken to establish the place of the avocado in the archaeological record. Today they grow in Tropical and Mediterranean climates and Mexico produces the vast majority of the world’s avocados.
So next time that you eat some avocado on toast remember the megafauna who preserved it for you! (The toast came later: but that’s another story!)
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