The need to locate distributed resources such as mates, food, and nests is
correlated with an enlarged hippocampus in many mammalian and avian species
. This correlation is believed to be a consequence of selection for spatial
ability. Little is known about how such ecological needs affect non-mammal
ian, non-avian species. In lizards, the putative hippocampal homologues are
the dorsal cortex (DC) and medial cortex (MC). We examined the relationshi
p between foraging ecology and the size of the DC and MC in congeneric male
lizards. We pre dieted based on the mammalian and avian literature that Ac
anthodactylus boskianus, an active forager that captures clumped, immobile
prey would have a larger MC and DC than A. scutellatus, a sit-and-wait pred
ator, that captures mobile prey. Our previous behavioral studies showed tha
t A. boskianus did not differ from A. scutellatus on a spatial task but tha
t A. boskianus was significantly better at the reversal of a visual discrim
ination, another task that is hippocampally dependent in mammals. In the cu
rrent study, we found that, relative to telencephalon volume, the MC and DC
were larger in the active forager whereas a control region, the lateral, o
lfactory, cortex, was similar in size between species. The current anatomic
al results suggest that MC and DC size is related to active foraging in liz
ards and, along with our previous behavioral studies, show that it is possi
ble for this relationship to occur in the absence of evidence for species d
ifferences in spatial memory. Copyright (C) 2000 S. Karger AG, Basel.