Maternal deprivation and the development of stereotypic behaviour

Abstract

Many farm, laboratory, zoo and companion animals experience some form of maternal deprivation. This is typically via separation from their mothers earlier than would happen in free-living populations, in some cases even while young are still dependent upon milk. Maternal deprivation may also occur in a qualitative way, via inadequate maternal care, perhaps caused by inexperience or by restrictive environments that limit maternal behaviours. In this paper we review evidence on the link between early separation from the mother and abnormal behaviour from a wide range of sources, including the early primate studies in this field, more recent examples from zoo and commercially reared animals, and human examples from studies of institutionalised children. We discuss factors that seem to influence the magnitude of later effects, such as developmental stage and age at separation, and whether separation is gradual (i.e. more similar to natural separation) or abrupt (as often the case in captivity). In these instances, however, maternal deprivation is just one aspect of a suite of changes that occur when infants are separated from their mothers. In the second part of the paper we therefore review the few cases where maternal loss per se has been investigated, and studies showing lasting affects of qualitative aspects of maternal care. We then look at the possible mechanisms underlying maternal deprivation-induced stereotypic behaviours including potential frustration of specific motivations, and lasting, more pervasive changes for instance in temperament or motor control. Finally, we discuss the practical and welfare implications of the effects of maternal deprivation, and suggest some topics for future research. #

Frustration and perseveration in stereotypic captive animals: Is a taste of enrichment worse than none at all?

“…As might be expected from the accounts above, providing enrichments but then removing them often exacerbates or even induces stereotypic behaviour; for instance removing the mother often triggers stereotypic attempts to escape or suckle in young mammals (reviewed [21]), while removing or delaying expected food rewards exacerbates pacing, weaving and sham-chewing in captive pigs and carnivores [16,23]. Less expected is that in some of these cases, the stereotypic behaviours of animals from whom complex natural stimuli are removed become even more prevalent and severe than those of subjects that have lived without enrichment all their lives.…”

Correlates of birth origin effects on the development of stereotypic behaviour in striped mice, Rhabdomys

“…Scores on one of our measures of perseveration, SA, also predicted the duration of time engaged in SB. These behavioural results thus suggest that, like deprivation-reared primates, and like deer mice developing in standard versus enriched housing conditions (Lewis et al 2006;Latham & Mason 2008), forebrain development is altered in CB animals in a manner that decreases both behavioural flexibility and the ability to inhibit inappropriate behavioural repetitions, with perseveration and SB being two outcomes of such a change. A second factor associated with SB was activity.…”

“…These findings suggest that both age at capture and sex may be important determinants of the behavioural phenotype of WC animals in laboratories, zoos and conservation breeding centres. Furthermore, since all the striped mice, even juvenile-caught, were captured post weaning age (after which time grassland striped mice are solitary; Schradin & Pillay 2005), this suggests that the physical aspects of environmental space and complexity, and/or an extended period of autonomous decision making, may underlie the effects of birth origin and not, for instance, that of the premature loss of parental care (a common confound in other CBeWC comparisons ;Mason 2006;Latham & Mason 2008). Instead of being stereotypic, WC striped mice were extremely inactive within their home cages, spending most of their time in their nestboxes when they otherwise would be expected to be active.…”

“…Although SBs afflict at least 10 000 captive zoo animals worldwide , in eight of the 11 species studied to date they are rare or absent in WC individuals, and more common in conspecifics born in captivity (Mason 2006;Latham & Mason 2008). The hypothesized causes of SBs are two-fold.…”

“…deprivation rearing or dosing with psychostimulants) correspondingly induce both perseveration and changes to these brain regions (e.g. Robbins et al 1990; Lewis et al 2006;Latham & Mason 2008). The likely causes of low/absent SB are therefore low motivational frustration, leading to the lack of repetition of source behaviours, and/or a well-functioning, species-typical forebrain that permits the ready inhibition of inappropriate behaviours.…”