[adolph]

The giant sloth was the first thing that came to my mind. Nearly every time I'm at the grocery I think about the giant ground sloth theory of avocado evolution:

  A number of authors, including Connie Barlow in her 2001 book The Ghosts of 
  Evolution, have speculated that the avocado is an "evolutionary anachronism" 
  with megafaunal dispersal syndrome (a concept originally proposed in the 
  1980s by Paul S. Martin and Daniel H. Janzen), arguing that the avocado 
  likely coevolved dispersal of its large seed by now-extinct megafauna. Barlow 
  proposed that the dispersers included the gomphothere (elephant relative) 
  Cuvieronius, as well as ground sloths, toxodontids, and glyptodonts. The 
  concept of evolutionary anachronisms/megafaunal dispersal syndrome has been 
  criticised by some authors, who note that many large fruit are readily 
  dispersed by non-megafaunal animals, with it being noted that living agoutis 
  disperse avocado seeds, with spectacled bears have also having been observed 
  eating domestic avocados.

https://en.wikipedia.org/wiki/Avocado

[TaurenHunter]

https://link.springer.com/article/10.1007/BF02904012

Early wild avocado seeds were smaller at around 2cm/.8in in diameter.

[gus_massa]

My aunt has a big avocado tree in the north west of Argentina. The avocato are very small, probably an inch long. They are very tasty, but you must collect a lot of them to prepare a dish.