Littermate presence enhances motor development, weight gain and competitive ability in newborn and juvenile domestic rabbits

Abstract

Interest has been growing in the influence siblings may have on individual development. While mammalian research has tended to emphasize competition among siblings for essential but often limited resources such as the mother's milk, there is also evidence of mutual benefits to be had from sibling presence, most notably for altricial young in enhanced thermoregulatory efficiency. In the present study we asked whether littermates of an altricial mammal, the domestic rabbit, might gain other developmental benefits from sibling presence. From postnatal days 1 to 25 we raised rabbit pups either together with their littermates or alone except for the brief, once daily nursing characteristic of this species, while controlling for litter size and ambient nest box temperature. At weaning on Day 25 the young were then transferred to individual cages. Before weaning, we found that pups raised separately from their littermates obtained less milk, and showed lower weight gain and slower development of the ability to maintain body equilibrium than their litter-raised sibs. This was the case even though the two groups did not differ in birth weight or in the ratio of converting milk into body mass in their temperature-controlled nest boxes. Postweaning, the isolation-raised animals were also less successful in competing for food and water when tested after deprivation than their litter-raised sibs. The present study adds to the growing evidence of the influence, in this case positive, that sibs (or half sibs) may have in shaping one another's development.

The effect of siblings on early development: A potential contributor to personality differences in mammals

“…Rödel, Hudson, et al, 2008;Rödel, von Holst, & Kraus, 2009). They also show better suckling performance, more rapid motor development, and greater success in competing for food and water at weaning (Nicolás et al, 2011). Within-litter differences in growth and behavior are accompanied by clear physiological differences.…”

“…Since many mammalian young actually spend more time with their sibs than with their parents, siblings can be expected to have a significant impact on each other's physical, psychological, and behavioral development. In fact, sibling relations represent a rich combination of costs and benefits for young animals confronting the challenges of an often hostile physical environment and struggling to obtain sufficient, usually limited resources (Bautista, Drummond, Martínez-Gómez, & Hudson, 2003;Nicolás, Martínez-Gómez, Hudson, & Bautista, 2011;Rödel, Starkloff, Bruchner, & von Holst, 2008;reviews in Hudson & Trillmich, 2008;Sulloway, 2010). Our examples are drawn from our own experience with four litter-bearing species commonly used in psychobiological and biomedical research: the domestic and wild European rabbit (Oryctolagus cuniculus), the laboratory rat (Ratus norvegicus), the domestic cat (Felis silvestris catus), and the laboratory mouse (Mus musculus).…”

The early-life environment of a pig shapes the phenotypes of its social partners in adulthood

“…As a consequence, individual development is increasingly affected by social interactions among litter mates. These experiences in early life may shape individual phenotypes later in life (Stockley and Parker, 2002), including behavior and social skills (Branchi, 2009; Hudson et al , 2011; Nicolas et al , 2011). Though there has been a strong research focus on the interactions between mother and offspring, the consequences of the early-life environment for the development of social effects that individuals express on traits of their social partners later in life have received limited attention (but see Rice et al , 2008; Ahern and Young, 2009).…”

How self-organization can guide evolution

“…Furthermore, the effects of birth weight on many aspects of later development are similar to the effects of litter size; for example pre-weaning weight gain and the development of motor coordination are both improved in heavier pups [41,42], but they are also improved in pups raised in litters compared with those reared in isolation [43]. We might speculate that since first exploiting the thermoregulatory benefits of huddling, evolution may have later exploited a variety of possible benefits of social thermoregulation for later development [44–48].…”