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The temporal and spatial distribution of above-ground activith in Merriam's kangaroo rats, Dipodomys merriami, radio-tracked during 10 winters varied in relation to phases of the moon. At the full moon, animals were more likely to be found in their day burrows at scheduled hourly radio fixes, and when they emerged, they stayed closer to home. At partial moon phases, above-ground activity was preferentially allocated to hours when the moon was down. As predicted from an extension of Rosenzweig's (1974, J. Mammal., 55, 193–199) model of optimal above-ground activity, the suppression of nocturnal activity at the full moon was partially offset by relatively great activity at dusk and dawn, and losses to nocturnal...
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We observed radio-implanted Merriam's kangaroo rats disposing of 10-g bonanzas of rolled oats in 48 trials in the field. The principal determinant of the initial disposition of discovered food was apparently its distance from the day burrow: food found within about 10m was mainly larder hoarded, whereas food encountered farther afield was usually dispersed immediately in shallow caches. Cache sites were newly dug for the purpose and not reused; most caches were nearer the current day burrow than was the food source, but a few were placed far from both the cacher's day burrow and its habitual nocturnal range. An experiment with artificial caches indicated that security from discovery increases with spacing and with...
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