Age differences in arousal and vigilance in California ground squirrels (Spermophilus beecheyi)

Newly emerged pup, juvenile, and adult California ground squirrels (Spermop hilus beecheyi douglasii) were videorecorded at a seminatural field site in northern California. Video data revealed age differences in the budgeting of ground squirrel behavior habitat use, and physiological arousal as indic ated by morphometric analyses of tail piloerection. Adults and juveniles de voted their time to foraging in the open at feeding stations while displayi ng low to moderate levels of arousal, respectively. Pups remained vigilant on the fringe of covered habitats while displaying comparatively higher lev els of arousal. Higher pup arousal may facilitate memory formation during e arly stages of development. (C) 2001 John Wiley & Sons, Inc.