The Paw Paw, a Favored Fruit of the Mastodon

A large exotic fruit used to be a common component of North America’s virgin bottomland forests.  The paw paw (Asimona triloba), also known as the prairie banana, the Hoosier banana, the Michigan banana, and the custard apple is the only temperate member of a tropical family of fruit trees.

Paw paw fruit cut in half.

It looks delicious and is related to the cherimoya which can occasionally be found in some supermarkets.  Reportedly, paw paws taste like banana custard, a rich flavor that some love but others find too cloying.  Unfortunately, when shipped, it turns to brown mush, so unless the curious epicure has a tree in their neighborhood, they’re out of luck.  I’ve wanted to try this fruit for decades but have been frustrated–none grow in the second growth woods around Augusta, Georgia.  I did come across some on a hike through the Congaree Swamp in South Carolina many years ago, but the fruit wasn’t ripe in July–it ripens in September and October.   I have tasted cherimoya which is flavored like a cross between a pear and a pineapple.

Paw paws are still found in the wild today but are rare because they require shade to grow.  98% of North American forests have been cleared at one time or another, and once the virgin forest canopy is eliminated, paw paws don’t return.   Horticulturalists are breeding the trees for home gardeners, however.

Paw paws have large seeds that can go right through an animal’s digestive tract without being destroyed.  A number of scientists believe this species was dependent on the alimentary tracts of mastodons and giant ground sloths for dispersal.  No herbivore living in North America today is able to swallow the seeds whole.  Paw paws are only found in the wild alongside rivers and streams, despite growing well on upland sites when transplanted by humans.  Following the extinction of the megafauna, flooding was the only way the seeds could spread, explaining why they’re only found in the wild near waterways.  But during the Pleistocene, when mastodons and sloths ate the fruit, they carried them to upland sites and defecated the viable seeds there, so it’s likely this fruit had a more continous range then than it does today. 

Fossils of paw paws are known from as early as 50 million years ago during the Eocene.  It’s possibly an older species than that, being a food of dinosaurs as well.  Most of the family is tropical, but at least this species was able to adapt to temperate climates that began with the coming of the Pleistocene.

(I’ll send a free copy of my book to anyone who will ship paw paw seeds and/or fruit to me.)

Tags: Asimona triloba, custard apple, giant ground sloths, Hoosier banana, mastodons, Michigan banana, paw paws