韋恩食記

thermoregulation 體溫調節
https://zh.wikipedia.org/wiki/%E9%AB%94%E6%BA%AB%E8%AA%BF%E7%AF%80

In contrast to mammals and birds, amphibians are unable to produce thermal energy through their metabolic activity, which would allow them to regulate their body temperature independent of the surrounding or ambient temperature. 與晡乳動物和鳥類相反，兩棲類動物不能通過它們的代謝活動產生熱能，這將使它們能夠利用周圍溫度或環境溫度來調節體溫。

However, the idea that amphibians have no control whatsoever over their body temperature has been proven false because their body temperature does not always correspond to the surrounding temperature. 然而，兩棲類動物完全不能控制其體溫的說法已被證明是假的，因為他們的體溫並不總是與周圍的溫度相對應。

While amphibians are poor thermoregulators, they do exercise control over their body temperature to a limited degree. 儘管兩棲類在溫度調節上比較薄弱，他們會在有限的程度上控制他們的身體溫度。

Physiological adaptations can assist amphibians in colonizing habitats where extreme conditions prevail. 生理適應性可以幫助兩棲動物在極端條件的棲息地生存。

The tolerance range in body temperature represents the range of temperatures within which a species can survive. 體溫的耐受範圍代表一個物種可以生存的溫度範圍。

One species of North American newt is still active when temperatures drop to -2ºC while one South American frog feels comfortable even when temperatures rise to 41ºC — the highest body temperature measured in a free — ranging amphibian. 當溫度降到-2°C時，一種北美蠑螈依然活躍，而即使溫度上升到41°C，南美洲青蛙依然感覺舒適，這是在自由放養的兩棲動物中測到的最高體溫。

☐ Recently it has been shown that some North American frog and toad species can survive up to five days with a body temperature of -6ºC with approximately one-third of their body fluids frozen. 最近有證據表明，一些北美青蛙和蟾蜍的物種可以在體溫-6°C並且大約三分之一的體液凍結的情況下生存五天。

☐ The other tissues are protected because they contain the frost-protective agents glycerin or glucose. 它們的其他組織受到保護，因為這些組織包含防凍劑甘油或葡萄糖。

☐ Additionally, in many species the tolerance boundaries are flexible and can change as a result of acclimatization (long-term exposure to particular conditions). ☐
此外，許多物種的忍受極限是彈性的，可以適應變化而變化（長期暴露於特定的條件下）。

Frog species that remain exposed to the sun despite high diurnal (daytime) temperatures exhibit some fascinating modifications in the skin structure that function as morphological adaptations. 儘管白天溫度高，暴露在太陽下的青蛙物種在皮膚結構中產生了一些有趣的改變，其作用是形態適應。

Most amphibian skin is fully water permeable and is therefore not a barrier against evaporation or solar radiation. 大多數兩棲動物的皮膚是完全透水性的，因此不是一種阻擋蒸發或太陽輻射的屏障。

The African savanna frog Hyperolius viridiflavus stores guanine crystals in its skin, which enable it to better reflect solar radiation, thus providing protection against overheating. 非洲大草原的青蛙Hyperolius viridiflavus在其皮膚裡儲存鳥嘌呤晶體，使它能夠更好地反射太陽輻射，從而提供對過高溫度的保護。

The tree frog Phyllomedusa sauvagei responds to evaporative losses with gland secretions that provide a greasy film over its entire body that helps prevent desiccation (dehydration). 樹娃Phyllomedusasauvager應對蒸發損失的方法是通過腺分泌物在其整個身體提供油脂薄膜，有助於防止乾燥(脫水)。

However, behavior is by far the most important factor in thermoregulation. 然而，行為是迄今為止在體溫調節中最重要的因素。

The principal elements in behavioral thermoregulation are basking (heliothermy), heat exchange with substrates such as rock or earth (thigmothermy), and diurnal and annual avoidance behaviors, which include moving to shelter during the day for cooling and hibernating or estivating (reducing activity during cold or hot weather, respectively). 行為的體溫調節中最主要元素的是曬太陽(取暖)，與基材如岩石或泥土等熱交換(地熱)，和每日或每年的迴避行為，包括移動到庇護地去冷卻和冬眠或夏眠(分別在過冷或過熱的天氣減少活動)。

Heliothermy is especially common among frogs and toads: it allows them to increase their body temperature by more than 10ºC. 取暖在青娃和蟾蜍中是特別常見的：這使得他們能夠提高體溫超過10°C。

The Andean toad Bufo spinulosus exposes itself immediately after sunrise on moist ground and attains its preferred body temperature by this means, long before either ground or air is correspondingly warmed. 安第斯蟾蜍Bufo spinulosus在日出後立即將自身暴露在潮濕地面上，早早在地面或空氣溫度升高之前，通過這種方式達到其喜好的體溫。

A positive side effect of this approach is that it accelerates the digestion of the prey consumed overnight, thus also accelerating growth. 這種方法的正面副作用是，它加速了晚上對獵物的消化，從而也加速增長。

Thigmothermy is a behavior present in most amphibians, although pressing against the ground serves a dual purpose: heat absorption by conductivity and water absorption through the skin. 地熱是大多數兩棲動物常見的行為，雖然緊貼地面有雙重目的：通過導電性吸熱和通過皮膚吸收水分。

The effect of thigmothermy is especially evident in the Andean toad during rainfall: its body temperature corresponds to the temperature of the warm earth and not to the much cooler air temperature. 在降雨的時候，地熱的效果在安第斯蟾蜍尤其明顯：它依據溫暖的地面溫度調節體溫，而不是與更冷的空氣溫度相對應。

Avoidance behavior occurs whenever physiological and morphological adaptations are insufficient to maintain body temperature within the vital range. 避免行為會在生理和形態的適應不足以將身體的溫度保持在重要範圍內時發生。
Nocturnal activity in amphibians with low tolerance for high ambient temperatures is a typical thermoregulatory behavior of avoidance.  對周圍溫度有著比較低的耐受性的兩棲動物的夜間活動是一種典型的逃避式體溫調節行為。
Seasonal avoidance behavior is extremely important in many amphibians. 季節性迴避行為在許多兩棲類動物中極為重要。
Species whose habitat lies in the temperate latitudes are confronted by lethal low temperatures in winter, while species dwelling in arid and semi-arid regions are exposed to long dry, hot periods in summer. 溫帶地區的物種的棲息地在冬季會面臨著致命的低溫，而居住在乾旱和半乾旱地區的物種會暴露於長期乾燥炎熱的夏天。

In amphibians hibernation occurs in mud or deep holes away from frost. 兩棲動物的冬眠發生在冬眠發生在遠離霜凍的泥漿或深孔中。

North of the Pyrenees Mountains, the natterjack toad offers a good example of hibernation, passing the winter dug deep into sandy ground. 比利牛斯山脈以北，natterjack蟾蜍為冬眠提供了一個很好的例子，通過挖掘到沙地深處度過冬季。

Conversely, natterjacks in southern Spain remain active during the mild winters common to the region and are instead forced into inactivity during the dry, hot summer season. 相反，在西班牙南部的natterjacks在該地區常見的暖冬仍然活躍著，但是不得不在乾燥、炎熱的夏季處於休眠狀態。

Summer estivation also occurs by burrowing into the ground or hiding in cool, deep rock crevasses to avoid desiccation and lethal ambient temperatures. 夏眠也是通過鑽入地下或隱藏在陰涼、深處的岩體裂隙來實現，這樣能避免干燥和致死溫度。

Amphibians are therefore hardly at the mercy of ambient temperatures, since by means of the mechanisms described above they are more than able to exercise some control over their body temperature. 因此，兩棲類動物是不受環境溫度控制的，因為通過上述的機制，他們對他們身體的溫度進行了控制。