Avocados actually evolved alongside giant ground sloths during The Cenozoic Era.

The giant sloths and their giant friends—including the Toxodon (who was sort of what you would get if you combined a rhinoceros and a hippo), the Glyptodon (a really big armadillo) and the gomphotheres (a crazy-looking elephant with a couple extra tusks)—devoured avocados whole.

Being giant themselves, passing giant avocado pits wasn’t a problem and they happily deposited the seeds (along with some extra fertilizer) across the American continent.

Unfortunately for avocados, those guys disappeared from the earth roughly 13,000 years ago. These days, there are not many massive mammals able to poop out a pit that size—and avocados haven’t yet gotten the memo.

By about 5,000 BCE, humans had arrived on the scene and were cultivating avocados for consumption (back then they were called ahuacatl—the Aztec word for testicle—because, well, just look at them). But scientists still wonder at how avocados and other so-called “anachronistic fruits” managed to survive until then, without giant sloth friends to spread their seeds.

Horses, jaguars, and even squirrels have all been floated as potential purveyors of the pits but no one knows for sure.

Either way, we owe a lot to the giant pooping sloths of yesteryear for doing their part to spread avocados across the land—not to mention the brave struggle avocados undertook to survive all those years after they were gone.

Enjoy the Reddit comments, Geege. :)

https://reddit.com/r/todayilearned/comments/3s79m4/til_the_only_animal_large_enough_to_eat_avocados/

Thank you, Panda Juan Canoli!  Reddit is so educational!

Biologist here! (No, not him.)

Although they weigh less than a pound, resplendent quetzals are plenty big enough toswallow avocados whole and disperse the pits.

A. How the fuck, or B. Do they just eat the ones that haven't grown as large and avocados just have fruits with indeterminant growth?

Wild avocados are smaller than domesticated ones. The pits are basically the same size, but the fruit is less fleshy. Ever see a pelican swallow a fish whole. Kind of like that, except the pit gets regurgitated since it's too big to pass. 

I thought you were just saying that quetzals are a resplendent creature. TIL'd.

(Eventually EVERYONE gets a nickname.)(Emily is Doodlebug.)

Wait wait... are you saying you guys DO NOT eat the avocado pits and poop them out?!?!

I frequently feel as if I'm TRYING to....

Trying to eat an avocado pit?!

Must I clarify?!

I just look at the size of an avocado pit and say no way I'm even trying. 

Not to turn this into a star wars thread, but I saw this trailer.  Everyone in the theater laughed.

Ha! Zootopia looks like it'll be entertaining. 

I was referring to HF's "...and poop them out?!?!"  :)

Simple physics. What goes in MUST eventually come out.