圖片來(lái)源：National Veterinary School of Alfort
一群睡著的兔寶寶并不僅僅是看起來(lái)可愛(ài)——它們對(duì)于種群的延續(xù)也很重要,。
新降生的小兔子會(huì)為了媽媽的奶水而展開(kāi)競(jìng)爭(zhēng),，而成功的幼崽則會(huì)長(zhǎng)得更加結(jié)實(shí)，并更有可能將它們的基因傳遞給下一代,。
然而根據(jù)本月發(fā)表在《科學(xué)公共圖書(shū)館—綜合》上的一項(xiàng)研究成果,，作為競(jìng)爭(zhēng)對(duì)手，這些兄弟姐妹們會(huì)擱置分歧,，彼此保護(hù)以抵御寒冷,。
利用紅外攝像機(jī)，以及一些溫度從23攝氏度緩慢降至11攝氏度的房間,，英國(guó)格拉斯哥大學(xué)的動(dòng)物學(xué)家Dominic J. McCafferty和同事發(fā)現(xiàn),，當(dāng)溫度降低后，生下來(lái)不足5天的沒(méi)毛兔寶寶會(huì)擠在一起取暖,。
就像投資者聯(lián)合創(chuàng)業(yè)一樣,，這種合作會(huì)花費(fèi)較少的個(gè)體成本。
這是因?yàn)槔蒙眢w的脂肪產(chǎn)生熱量會(huì)耗費(fèi)氧氣,，而使用太多的氧氣則會(huì)阻礙小兔子的生長(zhǎng),。但是通過(guò)分享熱量，兔寶寶能夠互相確保它們的兄弟姐妹不會(huì)使用太多的能量來(lái)抵御寒冷,，從而有助于全部存活下來(lái),，為今后種群的發(fā)展作出貢獻(xiàn)。（生物谷 bioon.com）
doi:10.1371/journal.pone.0033553
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PMID:
Private Heat for Public Warmth: How Huddling Shapes Individual Thermogenic Responses of Rabbit Pups
Caroline Gilbert1, Dominic J. McCafferty, Sylvain Giroud, André Ancel, Stéphane Blanc
Background Within their litter, young altricial mammals compete for energy (constraining growth and survival) but cooperate for warmth. The aim of this study was to examine the mechanisms by which huddling in altricial infants influences individual heat production and loss, while providing public warmth. Although considered as a textbook example, it is surprising to note that physiological mechanisms underlying huddling are still not fully characterised. Methodology/Principal Findings The brown adipose tissue (BAT) contribution to energy output was assessed as a function of the ability of rabbit (Oryctolagus cuniculus) pups to huddle (placed in groups of 6 and 2, or isolated) and of their thermoregulatory capacities (non-insulated before 5 days old and insulated at ca. 10 days old). BAT contribution of pups exposed to cold was examined by combining techniques of infrared thermography (surface temperature), indirect calorimetry (total energy expenditure, TEE) and telemetry (body temperature). Through local heating, the huddle provided each pup whatever their age with an ambient “public warmth” in the cold, which particularly benefited non-insulated pups. Huddling allowed pups facing a progressive cold challenge to buffer the decreasing ambient temperature by delaying the activation of their thermogenic response, especially when fur-insulated. In this way, huddling permitted pups to effectively shift from a non-insulated to a pseudo-insulated thermal state while continuously allocating energy to growth. The high correlation between TEE and the difference in surface temperatures between BAT and back areas of the body reveals that energy loss for non-shivering thermogenesis is the major factor constraining the amount of energy allocated to growth in non-insulated altricial pups. Conclusions/Significance By providing public warmth with minimal individual costs at a stage of life when pups are the most vulnerable, huddling buffers cold challenges and ensures a constant allocation of energy to growth by reducing BAT activation.
