Effects of differential infantile handling upon weight gain and mortality in the rat and mouse.

Animals were handled during ages 1 to 10, 11 to 20, or 1 to 20 days, or were nonhandled controls. Animals handled for 20 days weighed the most in adulthood, while the controls weighed the least. Animals handled on days 1 to 10 survived food and water deprivation the longest of any group. Mice handled for 20 days died earlier than controls, while the reverse was true for the rat.