Continuous recording of maternal behaviour in Rattus norvegicus

doi:10.1016/S0003-3472(69)80019-9

Animal Behaviour

Volume 17, Issue 4, November 1969, Pages 722, IN9, 723-729

https://doi.org/10.1016/S0003-3472(69)80019-9 Get rights and content

Summary

It was assumed that the time a lactating rat spends with its litter can be taken as a reflection of maternal behaviour. This was measured continuously in a dual-chambered apparatus which permitted the female to be with or away from its litter for any amount of time at any time of the day. It was found that the total time and the duration of each period that the mother spends with its litter shows an orderly decrease over the 21 days post-partum. Further analyses of these data indicated that there is a 24-hr rhythm in maternal behaviour. The rhythm appears to be inversely related to and may be a direct reflection of the rat's characteristic 24-hr activity cycle.

A comparison of the time spent with the litter with data obtained from a modified version of Seitz's maternal-behaviour scale yielded similar changes over time for those tests of the scale which did not involve any disruption of the ongoing behaviour of the mother or litter. Otherwise, there was no consistent relationship between these two measures or within the scale itself. Administration of the maternal-behaviour scale to females rearing litters in a single cage indicated that the above findings could be attributed to the use of the dual-chambered apparatus. These data further suggested that some aspects of the maternal-behaviour scale may be artifacts of the conditions of housing or method of administration, and may reflect emotional reactivity rather than maternal behaviour, per se.

The continuous recording of maternal behaviour was also found to differentiate between females rearing large and small litters. The time spent with the litter over the 21-day post-partum period decreased more rapidly in females rearing litters of twelve than in females rearing litters of four animals.

The data are interpreted as support for the assumption that the time that a lactating rat spends with its litter can be taken as a reflection of maternal behaviour. The main advantages of this procedure are that it provides a continuous recording that is not subject to sampling error or experimenter bias, and it takes advantage of the ongoing mother-litter interactions which are initiated by the animals themselves rather than forced by the proximity of a single cage or by the intervention of an experimenter.

References (6)

CarlierC. et al.
Effects of previous experience on maternal retrieving by rats
Anim. Behav.
(1965)
DeitchmanR.
Observational analysis of maternal behavior in irradiated and nonirradiated Wistar rats and its relation to later behavior in the pups
MoltzH. et al.
Maternal behavior of primiparous and multiparous rats
J. comp. physiol. Psychol.
(1965)

There are more references available in the full text version of this article.

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Continuous recording of maternal behaviour in Rattus norvegicus

Summary

Anim. Behav.

Observational analysis of maternal behavior in irradiated and nonirradiated Wistar rats and its relation to later behavior in the pups

Maternal behavior of primiparous and multiparous rats

J. comp. physiol. Psychol.