Natural Resources, School of


Date of this Version

April 1978


Published in Oecologia (Berlin) 35 (1978), 13–19. Copyright © by Springer-Verlag 1978. Used by permission.


The general conclusion of this paper is that heteromyids do not select seed sizes on the basis of their body size. My conclusion comes from the analysis of new data from central New Mexico, analysis of data in the literature on food habits of heteromyids, and a re-analysis of Brown and Lieberman (1973) and Brown (1975). All of these sources agree that no seed size selection exists.

Although no pattern of simple seed size selection was found, interesting differences were noticed among species. First, the tendency to husk appears to be related to the size of the rodent. Second, large heteromyids may depend on fruiting heads made up of small seeds. This may or may not have significance to the coexistence of heteromyid communities. At present, insufficient data are available to make conclusions along these lines.

Intuitively satisfying hypotheses, such as seed size allocation by heteromyids, are normally very hard to lay to rest. It is my hope that this paper demonstrates the weight of evidence is against seed size allocation in heteromyids, Those who wish to maintain this hypothesis, or reveal that it or related hypotheses have anything to do with heteromyid coexistence, must now produce data to support their position.