Monkey brains are back! For the moment, at least. In a series of confounding discoveries over the past month, the iconic (and supposedly locally extinct) fruit of the Jemicy recess culture reappeared in all its lumpy green glory. First, one half-eaten, its seeds clearly scavenged by squirrels, and an intact fruit found down by the stream. Then they began to appear daily, two or three at a time. Someone left one as a gift on my desk. I was completely stymied. Where could they have come from?
The kids were not bothered by this mystifying turn of events, but excitedly fanned out in search of more. I wondered out loud, to anyone who would listen, “How can this be? The only tree for a mile around was cut down in June for the new gym construction. No way would squirrels have dragged these fruit here from a tree far away. No, that would be more like something a human would do…”
As I contemplated this unlikely scenario before me, I realized that I was witnessing an anachronism – an instance of something existing out of its original time and place. It was, in fact, a double-anachronism. Monkey brain trees, Osage orange, Maclura pomifera, are a relic of the Pleistocene. They belong to a group of plants that evolved in conjunction with that era’s megafauna, such as wooly mammoths and giant ground sloths. In their native habitat of the southern midwest, monkey brain fruit would have been prized food for these browsers. The trees themselves have large thorns that would have deterred animals from consuming the leaves. Once the fruit were ripe and had fallen, they would be eaten in their entirety and their seeds carried away, to pass intact through the gut and be dispersed in fertile dung.
Monkey brain trees arrived in Maryland courtesy of that modern mega-disperser, human transport. They were planted as barrier hedges (thus the other nickname: hedge apples) and prized for the strength of their wood. The aromatic fruits were sometimes collected to use as centerpieces. Over time the Osage orange tree was cut more than planted, and relegated to scrubby field edges and roadsides, where squirrels shred them apart and eat their seeds without dispersing them.
So, the Jemicy kids who continue to collect the fruit, carry it away, and hoard it in their forts until it rots, are putting a new twist on an ancient practice. As I watched some of the middle schoolers stashing them high in the fork of a tree, I realized that I was observing modern megafauna gathering fruit much as giant ground sloths had done millennia ago, but with the opposite intent – to cache rather than to consume.
As for the mystery of how monkey brains came to be in the Jemicy woods this fall, it was solved when another teacher admitted to bringing them in from a source near his house and scattering them about. So, once again, humans have taken over the job of spreading a species whose original dispersers are gone. Whether the seeds of any of these imported fruit will germinate and survive at Jemicy remains to be seen; if they don’t, it won’t be for lack of enthusiastic dispersal.