What the Mastodons Ate
I’ve been researching topics like “anachronistic fruit” for a short while now. In short, there are fruits and other plant characteristics that seem to exist for no good reason—that is until one takes into account extinct animals. One in particular is the avocado, the fruit and pingpong-ball-sized seed of which is too large to be consumed by any living seed disperser besides elephants and others that live no where near the growing range of avocados.
There are all kinds of other examples, which you can read about in Connie Barlow’s “The Ghosts of Evolution,” though the idea goes back further, in particular to a 1982 publication by ecologists Daniel Janzen and Paul Martin.*
Specifically I have been looking for examples of what extinct Pleistocene megafauna in Florida might have eaten. Animals like mammoths, mastodons, giant sloths, glyptodons, original North American equines etc., are cited extensively as the likely partners with much of the fruit now only spread by a secondary disperser, or not at all. Well, there’s a fascinating book called “First Floridians and Last Mastodons” that presents the results of Pleistocene finds in the Aucilla River of northwest Florida.
There are actually loads, so to speak, of preserved mastodon poop dug up from deposits in this river. Many are found in association with mastodon skeletal remains, leaving little doubt about who ate what. Mastodons ate all kinds of woody plants, lots of twigs it turns out. In addition, the analysis lists seeds of Melothria species, aka creeping cucumber.
Creeping cucumber fruit. It must have taken an awful lot of these to satisfy a mastodon.
I wrote a Miami Herald article on this vining plant recently, and I just find it so fascinating that mastodons ate the very same thing! I shouldn’t be surprised; lots of the plants around us were eaten by all kinds of now-extinct species, but I guess it just drives things home, that 12,500 years ago when a mastodon ate, digested and excreted creeping cucumbers, well it’s really not all that long ago.
The Joshua Tree—Why won’t someone disperse my seeds?
*Another clear example is the Joshua tree. Its range has been shrinking for thousands of years, ever since the extinction of the giant Shasta ground sloth, whose dung is found to contain Joshua tree fruit and seeds.
Kenneth Setzer 