Answer: They were favorite foods of Mastodons vacationing in the Redneck Riviera.
A fascinating question for any native plant enthusiast is, “how did pre-European peoples and creatures impact the modern flora?” That question will rattle any arbitrary definition of “native species.” There was much going on in Florida for the eons before the Nina, Pinta, and Santa Maria came sailing along.
In this blog we’ve glimpsed influence of ancient people on our plant life (CLICK), so this time we will shift to the “anachronistic megafauna” –great beasts of yesteryear. Not dinosaurs, but those dino-sized mammals whose bones still turn up around our state. A leader in Florida archaeology is Dr. Lee Newsom at Pennsylvania State University. Most of today’s material comes from her research with collaborators.
The tail end of the Pleistocene Epoch (approx. 2.6-million –12,000 years ago) wasn’t so far back. People were long-established in North America by then, and for company they had sabre-toothed cats, mammoths, camels, long-horned bison, giant sloths 13 feet tall, bear-sized armadillos, mastodons, and more zoological marvels right here in the Sunshine State. Some ancient animal remains still have projectile points stuck in them from bad days in the Pleistocene. Those mammoth creatures, many of them herbivores, no doubt had “a little” influence on the plant life.
Today’s headliners are mastodons. In some old Florida sinkholes, especially in the Aucilla River near Tallahassee, there remain massive deposits of beautifully preserved mastodon dung dating back slightly over 12,000 years. Back then the climate was drier, and the sinkholes were watering holes where mastodons gathered to feed, drink, and probably socialize, apparently mostly in the autumn, leaving tons of buried scat to tell us today what mastodons ate. Additional large herbivores probably contributed too, but research shows the dung to be overwhelmingly of mastodon origin.
They ate dozens of plant species, some of them characteristic of cooler habitats farther north today. One reason for plant species historically in the “wrong latitude” might be ancient climate differences, but hold on: not only are there northern species too far south, but also vice versa. Hot-climate “Florida” species occur “too far north” among more northerly mastodon remains. A likely explanation for the bidirectional displacements is mastodons relocating seeds in their guts, as modern elephants do. Evidence suggests the “Florida mastodons” perhaps shuttled between Florida and the Appalachian Region. Millennia of migrations would move a lot of plant species around. In Africa, elephant migrations have a major impact on forest ecosystems, including making them more elephant-friendly. You might say the elephants eat what they prefer, spread the preferred species in their natural compost, trample down the competing vegetation, and create a positive feedback loop providing good eats along the path of life. They inadvertently invented horticulture.
If mastodons and other big herbivores participated in the evolution of North American floras, are there plant species adapted to the anachronistic megafauna? Dr. Newsom, citing earlier authors, suggests certain large fruits difficult for present-day herbivores to handle, including Honey Locust and Osage-Orange, both found in the mastodon castings.
Present-day elephants and long-gone mastodons liked gourds. Elephants and presumably their cousin mastodons bypassed the nasty rinds by crushing the gourds with their feet, then enjoying the smooshed gourd goo. Elegantly preserved gourd seeds pepper the preserved mastodon deposits. Interestingly, the preserved seeds are not the present-day “Okeechobee Gourd.” Also preserved perfectly in the doo, as if out of your aunt’s holiday nut bowl, are hazel nuts. I like them too.
By far the most abundant remains are Bald Cypress twigs. These are the bulk of it all, tons. Mastodons, and possibly other giant herbivores chomped young twigs off of Bald Cypress (Taxodium species) in truckload quantities.
And here we depart from true science and enter the fantasy world. As chewed upon at length in this blog some time ago, the “real purpose,” if any, of Cypress knees is a mystery. (CLICK) With no factual data whatsoever, casual biased personal observation leads me to suspect that Cypress knees seem to rise especially where there is physical disturbance (such as heavy hooves?). Please no e-mails—that disturbance notion is merely murky, not to be defended. And I have no idea to what extent the evolution of Cypress corresponded with the evolution of prehistoric giant herbivores in space and time. But all that admitted, could those big woody knees rising to impede all who pass be a Cypress’s way of telling a mastodon to go suck gourds?
Newsom, L.A., and M. C. Mihlbachler. Mastodons (Mammut americanum) Diet Foraging Patterns Based on Analysis of Dung Deposits. Springer. 2006.
Pleistocene Florida YouTube: http://www.youtube.com/watch?v=gmayKozVQ4w