An Experimental Study of Conflict and Fear: an Analysis of Behavior of Young Chicks Toward a Mealworm Part 11. the Behavior of Chicks Which Eat the Mealworm
Author: Hogan, Jerry A.
Source: Behaviour, Volume 27, Numbers 1-2, 1966 , pp. 273-289(17)
Abstract:I. A young chick that picks up a mealworm usually does not eat the mealworm immediately; rather, it runs for several seconds with the mealworm in its bill before smashing and swallowing it. This paper examines the hypothesis of KRUIJT (1964) that food-running is an ambivalent activity, being a mixture of a tendency to manipulate the prey and to flee. II. More than 100 Junglefowl and domestic Silky chicks were tested. Most chicks where hatched in the incubator and raised in social isolation; a few were hatched and raised by a mother-hen. Mealworms were presented once a day, two or three times a day at 5-hr intervals, or five times a day at io-min intervals; for the first time on day 1, day 2, day 4, or day 7; under 0, 5, or 10 hrs of food deprivation; in the home cage and in two unfamiliar environments; and under the influence of alcohol. Size of the mealworm was also varied. Time taken to pick up a mealworm, time spent food-running, total time, and other behavior were recorded. III. There was a strong negative relation between time taken to pick up the mealworm and time spent running on the first two mealworm presentations (Fig. 1). The results from the isolated chicks show that except for the first one or two mealworms, experience with mealworms had little permanent effect on the behavior a chick showed toward subsequent mealworms over a period of at least two weeks and experience with more than 30 mealworms (Figs. 2a, 3, 4a). One of the most consistent findings among all chicks tested was an increase in food-running from the first to the second mealworm (Figs. 2, 3, 4, 5). The absolute amount of food-running shown with the first mealworm increased as the chicks grew older, but the general picture shown by all age groups was the same (Fig. 5). Food-running increased directly with the size of the mealworm (Fig. 6). Food-deprivation increased food-running and strange environments decreased food-running (Fig. 7) in a way very similar to the changes in general locomotion in the same situations (HOGAN, 1965, Fig. 3a). IV. The results show that KRUIJT'S hypothesis of the causation of food-running is oversimplified. Most of the results can be understood more easily if a tendency to flee from the mealworm is not considered as a unitary drive system, but rather as two drive systems - fear and withdrawal (locomotion) - which have mutually inhibitory relations. The role of a tendency to manipulate and eat the mealworm is not yet clear. The waning of food-running is most probably due to adaptation or habituation to the stimuli provided by a mealworm in the chick's bill.
Document Type: Research article
Publication date: 1966-01-01