But the great mammals disappeared forever about 13,000 years ago in the Western Hemisphere. Around that time, North America lost 68 percent of its diverse Pleistocene megafauna, and South America lost 80 percent, Connie Barlow, author of The Ghosts of Evolution: Nonsensical Fruit, Missing Partners, And Other Ecological Anachronisms says. But even after this major shift in the land mammal population, the wild avocado still requires the same method of seed dispersal, which makes it somewhat of an evolutionary anachronism.
“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.”
A fruit with smaller seeds, like a berry, for example, can be consumed whole and dispersed by small mammals, making the chances of fruiting in a new place higher.