Gomphothere Fruits: A Critique

The hypothesis that giant Pleistocene mammals shaped reproductive traits of many tropical plants could help explain anomalous fruits which appear adapted for animal consumption, but which lack contemporary dispersal agents. The "megafaunal fruit syndrome," however, is not yet a useful tool. It lacks consistent criteria, depends upon precarious ecological assumptions, and does not give adequate attention to the likelihood that megafaunal plants actually have effective contemporary dispersal agents in protected forests. If qualities of living animals are sufficient to explain dispersal adaptations of common tropical trees, guesswork about horses and ground sloths of the Pleistocene is superfluous. Even the scanty literature now available shows that nearly half of the megafaunal fruits have living dispersal agents, that seeds of some of these plants suffer catastrophic mortality if they are not dispersed, and that many megafaunal species are common in Central and South America where horses and cattle (thought to be surrogate Pleistocene dispersal agents) are absent. Few of these species are likely to be lingering anachronisms from the Pleistocene. The megafaunal syndrome must be refined with exclusive and ecologically sound criteria before it can be a useful tool in ecology.