The Avocado. Sitting there in your refrigerator. Or in your fruit bowl to ripen. You may never have given a second thought about the origin of the fruit, while consuming its delicious green meaty flesh. But the avocado is an aberration of nature – It is a total fluke that this fruit should be sitting in your home right now. In hypothetical evolutionary history, the avocado should no longer exist. It is infinitely more likely that the avocado would have been something studied as a fossil in museum, rather than sitting in the designer fruit bowl of every middle class family in the Western world. But this is a not hypothesis – This is reality, and the crazy, unlikely little nuggets of fortune in evolution are what make this place as vibrant and varied as we know it.
The avocado plant hit its evolutionary prime at the beginning of the Cenozoic era. This was an interesting epoch, when megafauna still roamed the earth in abundance. These creatures included Mammoths, Megatherium – giant ground sloths weighing up to 7 tons, and Gomphotheres – giant intelligent elephant-like animals, and many other fantastic beasts. These huge creatures roamed across most of the world. Megafauna by definition weigh over 1 metric ton, and many species of plant evolved along with these gigantic creatures. That’s where the avocado comes in. The avocado evolved to be attractive as food to these large animals, which would eat it whole. The behemoths would then travel considerable distances and of course, ultimately need to defecate. The avocado seed would then grow in a new place in its own ‘fertilizer pod’, thus proliferating the species. This is the avocado’s natural way of survival and propagation.
Then catastrophe strikes. The great megafauna mammals experienced a shattering extinction event about 13,000 years ago. At that time, North America lost 68% of its Pleistocene megafauna, whilst South America lost 80%. After the giant mammals had died out, normal evolutionary law states that the avocado should have died with the. Without the mechanism of seed dispersal they had evolved for, the avocado plant had no further way of dispersing its seeds except ground fall. This form of seed dispersal rarely works, as the seed would drop right next to the parent plant, at which point both would compete for the same resources of light and nutrients, eventually choking one or both. The avocado still requires the same method of seed dispersal, making it an evolutionary anachronism.
Connie Barlow, the author of The Ghosts of Evolution: Nonsensical Fruit, Missing Partners, And Other Ecological Anachronisms writes: “After 13,000 years, the avocado is clueless that the great mammals are gone,” Barlow explains. “Without larger mammals like the ground sloth to carry the seed far distances, the avocado seeds would rot where they’ve fallen and must compete with the parent tree for light and growth.”
So, how did the avocado survive? The answer is, no one knows. As far as science goes, it is an evolutionary failure. And yet, here it is in the world today. Rodents like squirrels or mice may have contributed to the avocados survival if they took and buried seeds in the ground, but this cannot explain the species survival in full. Wild avocados were appealing to megafauna because they had enough flesh to lure them in, and would be eaten in one bite.
One thing is for sure – When humans evolved to the point where we could cultivate the plant, we unwittingly took up where the megafauna had left off. Humankind gave the avocado a second wind. Maybe the avocado is not an evolutionary failure after all. Perhaps it just needed to buy a little time until it had ultimate success. Either way, through cultivation, humans bulked up avocados so there is much more flesh to eat. The avocado is now far more populous than it has ever been at any other point in history. The saga of the mysterious avocado, a ghost of evolution, continues.