Chisel-toothed Kangaroo Rat (Dipodomys microps), cheeks stuffed with seeds, photo credit Aaron Ambos (with permission).
This first offering is unabashedly personal and there’s backstory. I began opening stomachs of snakes preserved in museums in the early 1970s, for my master’s thesis on the feeding biology of venomous coralsnakes. Since then I have examined thousands of specimens of hundreds of species, from all over the world. Accordingly, when my then Berkeley graduate student Randy Reiserer set out to learn more about several species of rattlesnakes, I coached him on a methodology that had been fine-tuned over the decades: Make minimal belly incisions, centered on the stomach; curators want to minimize damage, and in the intestines, digested prey are no longer countable as individuals, more difficult to identify, indeterminate in terms of direction of ingestion (head-first etc.), and so forth—in short, don’t waste time looking in the hindguts.
Figure 1. Examples of germinated seeds from the lower intestines of rattlesnakes examined in this study. (a) Achnatherum hymenoides (Indian ricegrass). (b) Cryptantha pterocarya ( wingnut cryptantha). Arrows denote the root radicle tip. (From Reiserer et al.)
Early-on I checked in with Randy, was surprised to see a Sidewinder laid open stem-to-stern, and reminded him of my instructions, only to be asked, “Do you recognize these tiny objects scattered through the matted fur in the rattler’s intestines.” “No,” I replied, after a quick glance through his dissecting scope, “but don’t open the snakes all the way down, ok?” Minutes later my annoyance at being told to look again evaporated when I viewed an obvious sprouted seedling in that Sidewinder’s colon. Soon we were grinning—with not a little irony on my part—and planning to write up our discovery of seed dispersal by rattlesnakes. As has happened so often, serendipitous revelations of new natural history facts would modify how the ecological roles of these animals are viewed, and in this case it helped that a grad student didn’t blindly follow the instructions of his mentor.
