Wikipedia makes this interesting observation about avocados and mangoes:
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 existent native animal is large enough to effectively disperse avocado seeds in this fashion. If so, the avocado occupies an ecological niche similar to that of the mango of Asia.
This is a gomphothere.