幼いチンパンジーとその母親にとっての遊びの重要性(The Importance of Play for Young Chimpanzees and Their Mothers)

2024-03-15

2024-03-14 タフツ大学

新しい研究によると、チンパンジーの母親は、自分の子供の育成については余分な努力を惜しまないようです。ウガンダのキバレ国立公園での10年間の観察データを使用し、研究者らは成人はしばしば遊び、若いチンパンジーは遊ぶが、食料が不足すると成人は遊びを置き去りにして生存に焦点を当てることを発見しました。しかし、その間も、母親のチンパンジーは子供の主要な遊び相手であり続けます。これは、母親チンパンジーが食料不足の状況下でも、子供の身体的および社会的発達を促す不可欠な役割を果たすことを示唆しています。

<関連情報>

大人の社会的遊びの生態学的変化から、野生のチンパンジーにとって母親であることの隠れた代償が明らかになった Ecological variation in adult social play reveals a hidden cost of motherhood for wild chimpanzees

Kris H. Sabbi,Sophia E. Kurilla,Isabelle G. Monroe,Martin N. Muller,Richard W. Wrangham,Zarin P. Machanda
Current Biology Published:March 14, 2024
DOI:https://doi.org/10.1016/j.cub.2024.02.025

Highlights

•Adult chimpanzees played more often with all partners when diet quality was high

•Unlike other dyads, only mother-offspring play persisted when diet quality was low

•Playing with offspring helps balance the costs of grouping with offspring needs

•Like with humans, parent-offspring play may be crucial to development for chimpanzees

Summary

Though common among humans, social play by adults is an uncommon occurrence in most animals, even between parents and offspring.¹^,²^,³The most common explanation for why adult play is so rare is that its function and benefits are largely limited to development, so that social play has little value later in life.³^,⁴^,⁵^,⁶Here, we draw from 10 years of behavioral data collected by the Kibale Chimpanzee Project to consider an alternative hypothesis: that despite its benefits, adult play in non-humans is ecologically constrained by energy shortage or time limitations. We further hypothesized that, since they may be the only available partners for their young offspring, mother chimpanzees pay greater costs of play than other adults. Our analysis of nearly 4,000 adult play bouts revealed that adult chimpanzees played both among themselves and with immature partners. Social play was infrequent when diet quality was low but increased with the proportion of high-quality fruits in the diet. This suggests that adults engage in play facultatively when they have more energy and/or time to do so. However, when diet quality was low and most adult play fell to near zero, play persisted between mothers and offspring. Increased use of play by adult chimpanzees during periods of resource abundance suggests that play retains value as a social currency beyond development but that its costs constrain its use. At the same time, when ecological conditions constrain opportunities for young to play, play by mothers fills a critical role to promote healthy offspring development.