Open-field behavior of prenatally irradiated and/or postnatally handled C57BL/6 mice.

Mice (C57BL/6) were prenatally irradiated with 60Co and/or handled on postnatal Days 1-10, and subsequently tested in an open field on Days 21, 42, and 63, and in a shuttle box on Days 30 and 60. Another group of mice was treated and tested similarly, but the shuttle box testing was omitted. All animals were cross-fostered at birth. Handling increased open-field activity and decreased defecation whereas irradiation decreased activity and had inconsistent effects on defecation. A comparison of the data from both groups of mice indicated that the shuttle box experience decreased open-field activity, particularly for the irradiated and unhandled animals. Direct and indirect irradiation effects--revealed by the cross-fostering procedure--were both significant and about equal in magnitude, underlining the importance of attending to irradiation effects on maternal as well as on offspring behavior.

Modification of the response to separation in the infant rhesus macaque through manipulation of the environment.

Rhesus mother-infant pairs were housed in a playpen apparatus beginning just before the birth of four male infants. The infants were separated from their mothers four times beginning at a mean age of 218 days. In Type A separations (I and IV) the infants were removed and housed away from their familiar environment in a protected setting; in Type B separations (II and III) the infants remained in the familiar setting and mothers were removed. One pair was separated every 2 weeks for 6 days; for a particular infant, a mean of 8 weeks intervened between each of the separations. On the basis of infant behavior during separation. Type B separations appeared to have a more deleterious effect on the infant: infants did not show the typical behavioral signs of depression under Type A housing conditions, whereas, under Type B conditions, infants expressed the typical depressive reaction to separation. However, comparisons of pre- and postseparation behaviors in the mother-infant pairs indicated that Type A separations were more perturbing. Increases in ventral-ventral contact between mothers and infants were greater following Type A separations and increases in time at nipple occurred only after Type A separations; infant grooming by mother increased only after the first, a Type A, separation. Type B separations may have affected mothers more severely in that reciprocity between maternal cradling and infant clinging was greater following Type B separations than following Type A separations when infants clung significantly more often than mother cradled.

Standards of morphological development of the quail, Coturnix coturnix japonica, embryo.

The morphologic growth of 290 Japanese quail embryos was analyzed to enable an assessment of the developmental status of an organism and permit the evaluation of experimental effects on development. The growth of 36- to 228-hr embryos was analyzed according to Hamburger and Hamilton's (1951) stages of development for the chick; the growth of 240-hr and older embryos was analyzed by correlating age with the length of 5 morphologic structures, toe, leg, beak, wing, and total. A correlation of +.99 was obtained for age-stage relations and a correlation of +.97 was found for age-structure length relations.

Olfactory, thermal, and tactual influences on infantile ultrasonic vocalization in rats.

The amount of time infant rats 3-13 days old spent emitting ultrasounds was greater when pups were placed in an empty dish than when placed in a dish containing clean bedding or soiled bedding from the nest. Pups from 5-13 days of age vocalized more when on the clean bedding than when on the soiled bedding. When placed on cloth covered dishes, pups vocalized most to the empty dish and least to the dish containing soiled bedding. The odor of clean bedding elicited less ultrasonic vocalization than the odor of the empty dish only when less than 7 days old. Pups vocalized more to room temperature than to heated conditions. The results indicate that olfactory, tactual, and thermal nest cues influence infantile ultrasonic vocalization in the rat.