求偶 Courting |
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蝙蝠的交配系統遠比我們想像的複雜且有趣。許多蝙蝠採行一夫多妻制。單一雄蝠支配數隻雌蝠，通常會負責保護棲所並在勢力範圍內展現視覺、聽覺和嗅覺性的複雜求偶儀式求歡，並阻止其他雄蝠接近。有的蝙蝠為一夫一妻制例如大雙紋蝠的近親細尾雙紋蝠，有的則為雜交型。
聽覺儀式極發達的槌頭果蝠有一雙氣囊可隨意充氣成擴音器，充滿整個胸腔迫使心肺向後及側面發展。連續的呱呱叫聲就像美國牛蛙，群聚時合唱聲可貫穿樹梢，用於建立交配秀場。夜間25-132隻蝙蝠在直徑10m的領域內聚集以叫聲和拍翅競技，雌蝠盤旋後擇一雄蝠配對。
大雙紋蝠基本社群為妻妾群由1雄與1-8隻雌蝠配對，雄蝠捍衛1-3㎡的領域，並表演精巧的視覺和聽覺展示以吸引妻妾群。
數個妻妾群約40-50隻蝙蝠成一個聚落。落單的雄蝠混入其中尋找自組妻妾群的機會，若是太靠近有主的妻妾群，被侵入的雄蝠僅會頻頻呼叫不會造成傷害。捍衛領域並競爭雌蝠的活動持續整年。妻妾群間的成員常互相移動，新來者會受排擠：在聚落附近單獨覓食。聚落內的覓食區由擁有妻妾群的雄蝠各自捍衛，僅容妻妾群內的雌蝠分享，並驅趕其他雄蝠。雌蝠也會驅趕群外的雌蝠。當一隻雌蝠改變妻妾群，覓食區亦須改變。
成年後的雌蝠飛離家族，雄蝠則留在家族附近以趁機接手或重組妻妾群。
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| Three basic types of mating system occur in bats. The first involves one male and many females (the group of harem)and is called polygamy. When males and females mate with more than one partner and there is no bond between mating pairs, this is called promiscuous. When the long-term relationships are maintained between individual males and females, it is a monogamous system.
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槌頭果蝠
Hypsignathus
monstrosus
有特殊的交配秀場的配對行為。
Hammer-headed fruit
bat had a 'lek" mating
system. |
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大雙紋蝠
Saccopteryx bilineata
交配系統為妻妾群。
Male white-lined bats
compete for the harem
by complicate courtship
ritual. |
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| 交配 Mating |
雙紋蝠除了繁複的求偶儀式外，雄蝠還會控制翼膜上囊狀的腺體發散某種費洛蒙以吸引異性。肩章果蝠的雄蝠在肩膀的腺囊上有白色肩章毛簇，在複雜的求愛過程中會從腺囊釋出分泌物助「性」。非洲甘比亞肩章果蝠從求偶到交配過程為：
(1) 雄蝠展示平常不顯見的肩章（視覺吸引）、飄散腺體分泌物（嗅覺吸引）並發出叫聲（聽覺吸引）以
誘惑雌蝠，
(2) 受誘惑的雌蝠飛向展示中的雄蝠，
(3) 雌蝠與雄蝠進行交配前的互動，
(4) 交配中的蝙蝠。交配時，雄蝠跨坐在雌蝠背後，並用雙翼和拇指摟住雌蝠，有時還用牙齒咬住雌蝠的
頸部皮毛。
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During the breeding season, the males would fly to a location and start to emit courting calls. The calls seemed to space out the males and attract females. While calling, the male would display the normally concealed epaulet (1). The female fly to the courting male (2) and start to interact with the male (3). During mating, the male mount the female from the rear, typically using wings and the thumbs to restrain the female (4).
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| 孕育 Breeding |
蝙蝠是哺乳動物因此行體內受精，雌性在胸前有一對乳房供哺乳，有的在腹部有一對假乳供幼蝠攀附。懷孕期平均約兩個月。幼蝠出生時裸禿無毛，也無活動能力。
雄蝠有醒目的陰莖，睪丸能輕易從腹腔移到陰囊的位置。大蝙蝠的雄性陰莖很像某些靈長類，但是牠們幾乎不管育兒事務。
蝙蝠的交配期、繁殖期及冬季遷移和排卵受精等的時間表因種類而有極大差異。冬眠型的蝙蝠多數會在秋季交配，往往雌雄成群飛行。
有的蝙蝠（例如長指蝠）排卵和交配同時進行，受精隨之發生，但發育過程緩慢經過整個冬天，直到春天才生小蝙蝠。
溫帶地區的蝙蝠會先交配，將精子存在雌蝠的生殖道中，直到春天才排卵受精（例如淡黃家蝠），胚胎著床到分娩的妊娠期至少約需44天。有的雄蝠有時將精子存在尾部的副睪，在冬眠期甦醒時或是春季冬眠一結束時，立即交配，確保春季受孕，好掌握溫帶短暫的夏季撫育幼蝠。
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The reproductive patterns of bats are various depending on the species. Long-fingered bat mate in the fall, fertilization occurs shortly thereafter, embryonic development is retarded through hibernation, and the young are not born until spring.
Eastern pipistrelle has two mating periods per year: one in the fall followed by storage of the sperm in the uterus of the female during hibernation, and a second in the spring followed by ovulation. Gestation, as measured from implantation to parturition, lasts at least 44 days.
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帥氏長指蝠
Miniopterus schreibersi
Schreibers's long-fingered bat |
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黃果蝠
Eidolon helvum
Straw-colored fruit bat |
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| 哺育 Nursing |
幼蝠出生時體型碩大體重甚至可以達到母蝠的40%，換算成人的比例就是50公斤的母親產下20公斤的巨嬰，通常三週就和成蝠一樣大並能飛行。
蝙蝠在棲所內分娩，母蝠生產時倒掛著身體，有些以拇指攀壁固定並以尾膜充作搖籃承接新生兒。幼蝠出生時尾先頭後（俗稱臀位分娩）以免雙翼卡住產道，此時拇指及腳發育良好但雙翼尚未完全，會用爪子緊抓母蝠，將自己的上半身拉出產道，然後開始移動尋找母蝠腋下的乳頭。
幼蝠還小時夜晚成群倒掛留置棲所，母蝠出外覓食但會回到棲所數次餵食，直到白天母蝠回來，再安穩的藏入母蝠腋窩下，緊貼著乳頭。多數的母蝠每胎只生一隻幼蝠，少數會生雙胞胎。生三或四胞胎，對乳頭只有一對的母蝠在哺育時十分困難。特殊的是灰毛尾蝠，母蝠有四個乳頭，常一口氣生四隻幼蝠，也無後顧之憂。
哺乳期依種類而異一般約為1.5至2個月。群體生活的蝙蝠其幼蝠棲所像是大型托兒所，母蝠全憑一點空間概念以及叫聲和氣味才能從全部裸禿的幼蝠中，找到自己的孩子，進行授乳，辨識過程要花上一小時。
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Baby bats are enormous at birth and may weigh up to 40% of their mother's weight. Young bats grow very quickly and can fly about 18 days. Producing such large baby makes the birth process difficult.
Baby bats are born bottom-first, which is known as a breech presentation in human. The arrangement minimizes the chances of the baby getting its wings tangled in the birth canal. Fortunately, their wings are tiny compared to those of an adult. The thumbs and hind feet, are virtually adult-sized at birth so that the newborn can cling to its mother or to a roost.
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長鼻蝠
Rhynchonycteris naso
Tufted bat
雌蝠與幼蝠因毛色近似地衣有保護色效果。 |
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