基本介紹

已知最(zui)早(zao)的(de)(de)(de)(de)(de)(de)(de)(de)松(song)(song)(song)(song)鼠(shu)(shu)類(lei)物種(zhong)(zhong)的(de)(de)(de)(de)(de)(de)(de)(de)化(hua)石來自始(shi)新(xin)(xin)世的(de)(de)(de)(de)(de)(de)(de)(de)地(di)層(ceng)。那是距今6500萬(wan)年～3500萬(wan)年前的(de)(de)(de)(de)(de)(de)(de)(de)久遠時(shi)代。那時(shi)恐龍剛(gang)剛(gang)滅絕(jue)不久，哺乳動物尚未(wei)在(zai)(zai)陸(lu)地(di)上取得控制權(quan)，青藏高(gao)原尚未(wei)成(cheng)為(wei)陸(lu)地(di)，歐(ou)(ou)洲(zhou)(zhou)(zhou)和(he)北(bei)美(mei)洲(zhou)(zhou)(zhou)仍然(ran)有陸(lu)地(di)相連，南美(mei)洲(zhou)(zhou)(zhou)則是一(yi)(yi)(yi)個(ge)巨(ju)大(da)的(de)(de)(de)(de)(de)(de)(de)(de)島嶼。最(zui)原始(shi)的(de)(de)(de)(de)(de)(de)(de)(de)松(song)(song)(song)(song)鼠(shu)(shu)生活在(zai)(zai)北(bei)美(mei)洲(zhou)(zhou)(zhou)，形態與今天的(de)(de)(de)(de)(de)(de)(de)(de)鼯(wu)鼠(shu)(shu)接近(jin)。在(zai)(zai)北(bei)美(mei)洲(zhou)(zhou)(zhou)晚始(shi)新(xin)(xin)世的(de)(de)(de)(de)(de)(de)(de)(de)地(di)層(ceng)中(zhong)還發現(xian)了(le)(le)一(yi)(yi)(yi)系列松(song)(song)(song)(song)鼠(shu)(shu)類(lei)物種(zhong)(zhong)的(de)(de)(de)(de)(de)(de)(de)(de)化(hua)石，不同于(yu)現(xian)在(zai)(zai)的(de)(de)(de)(de)(de)(de)(de)(de)任何(he)一(yi)(yi)(yi)類(lei)松(song)(song)(song)(song)鼠(shu)(shu)。北(bei)美(mei)洲(zhou)(zhou)(zhou)異常(chang)豐(feng)富(fu)的(de)(de)(de)(de)(de)(de)(de)(de)化(hua)石松(song)(song)(song)(song)鼠(shu)(shu)種(zhong)(zhong)類(lei)顯示(shi)，松(song)(song)(song)(song)鼠(shu)(shu)科(ke)起源(yuan)于(yu)始(shi)新(xin)(xin)世的(de)(de)(de)(de)(de)(de)(de)(de)北(bei)美(mei)洲(zhou)(zhou)(zhou)，并在(zai)(zai)之后的(de)(de)(de)(de)(de)(de)(de)(de)漫(man)長歲(sui)月中(zhong)輻射到了(le)(le)大(da)洋洲(zhou)(zhou)(zhou)以外的(de)(de)(de)(de)(de)(de)(de)(de)各大(da)洲(zhou)(zhou)(zhou)，在(zai)(zai)這個(ge)過程中(zhong)演化(hua)出(chu)了(le)(le)形態各異、適應(ying)各種(zhong)(zhong)環(huan)境的(de)(de)(de)(de)(de)(de)(de)(de)物種(zhong)(zhong)。在(zai)(zai)現(xian)存(cun)的(de)(de)(de)(de)(de)(de)(de)(de)嚙(nie)齒(chi)目松(song)(song)(song)(song)鼠(shu)(shu)亞目物種(zhong)(zhong)中(zhong)，主要分布于(yu)歐(ou)(ou)亞大(da)陸(lu)的(de)(de)(de)(de)(de)(de)(de)(de)睡鼠(shu)(shu)科(ke)和(he)分布于(yu)北(bei)美(mei)洲(zhou)(zhou)(zhou)的(de)(de)(de)(de)(de)(de)(de)(de)山河貍科(ke)與松(song)(song)(song)(song)鼠(shu)(shu)科(ke)有較近(jin)的(de)(de)(de)(de)(de)(de)(de)(de)親緣關系。而松(song)(song)(song)(song)鼠(shu)(shu)科(ke)是最(zui)為(wei)人熟知的(de)(de)(de)(de)(de)(de)(de)(de)松(song)(song)(song)(song)鼠(shu)(shu)家(jia)族成(cheng)員，也是分布最(zui)廣、種(zhong)(zhong)類(lei)最(zui)繁多的(de)(de)(de)(de)(de)(de)(de)(de)一(yi)(yi)(yi)個(ge)類(lei)群。

生長與分布

廣(guang)布(bu)于(yu)古北(bei)(bei)界溫(wen)帶和寒(han)溫(wen)帶森林生態系統中(zhong)，西起伊比利亞和大(da)不列顛島，東至堪察加(jia)半島、俄(e)羅(luo)斯薩哈林島和日本的北(bei)(bei)海(hai)道，南(nan)至地中(zhong)海(hai)、黑海(hai)、蒙古北(bei)(bei)部、中(zhong)國的西北(bei)(bei)和東北(bei)(bei)地區。

松鼠(shu)主要(yao)分布在(zai)由(you)松屬(Pinus)、落(luo)葉(xie)(xie)松屬(Larix)和云杉屬(Picea)樹種(zhong)構成的(de)針(zhen)葉(xie)(xie)林(lin)或針(zhen)闊混交林(lin)中(zhong)。由(you)于食(shi)物來源相對較(jiao)為豐富和穩定，松鼠(shu)在(zai)針(zhen)闊混交林(lin)中(zhong)可以(yi)維持較(jiao)高的(de)種(zhong)群密度(du)，并(bing)可以(yi)利用城(cheng)郊甚至城(cheng)市中(zhong)的(de)小片林(lin)地，成為伴(ban)人(ren)動(dong)物。

形態及特征

歐(ou)亞(ya)(ya)大陸(lu)北部溫(wen)帶針葉林帶廣泛分(fen)布(bu)的(de)(de)(de)歐(ou)亞(ya)(ya)紅(hong)(hong)(hong)松(song)(song)鼠(shu)(shu)(shu)（也(ye)(ye)稱北松(song)(song)鼠(shu)(shu)(shu)）是(shi)松(song)(song)鼠(shu)(shu)(shu)的(de)(de)(de)典(dian)型(xing)(xing)代表，也(ye)(ye)是(shi)大眾(zhong)熟(shu)知(zhi)的(de)(de)(de)松(song)(song)鼠(shu)(shu)(shu)形象(xiang)的(de)(de)(de)原型(xing)(xing)。分(fen)布(bu)在(zai)歐(ou)亞(ya)(ya)大陸(lu)東(dong)端的(de)(de)(de)歐(ou)亞(ya)(ya)紅(hong)(hong)(hong)松(song)(song)鼠(shu)(shu)(shu)冬季背毛(mao)(mao)黑而腹白，夏(xia)毛(mao)(mao)灰(hui)間棕紅(hong)(hong)(hong)色(se)；而分(fen)布(bu)在(zai)歐(ou)亞(ya)(ya)大陸(lu)西(xi)端的(de)(de)(de)歐(ou)亞(ya)(ya)紅(hong)(hong)(hong)松(song)(song)鼠(shu)(shu)(shu)背毛(mao)(mao)全年均(jun)為棕紅(hong)(hong)(hong)色(se)。灰(hui)間棕紅(hong)(hong)(hong)色(se)也(ye)(ye)是(shi)北美洲森(sen)林中多數(shu)松(song)(song)鼠(shu)(shu)(shu)的(de)(de)(de)主要色(se)調。歐(ou)亞(ya)(ya)紅(hong)(hong)(hong)松(song)(song)鼠(shu)(shu)(shu)在(zai)分(fen)布(bu)范圍內從東(dong)至(zhi)西(xi)不同地理群(qun)體毛(mao)(mao)色(se)的(de)(de)(de)變化也(ye)(ye)是(shi)歷史上松(song)(song)鼠(shu)(shu)(shu)從北美大陸(lu)起(qi)源，輻射進入歐(ou)亞(ya)(ya)大陸(lu)這一過程的(de)(de)(de)反映。

在(zai)(zai)中國(guo)(guo)，東(dong)北地區和(he)新疆的(de)(de)(de)泰加林是歐亞(ya)紅松(song)鼠(shu)的(de)(de)(de)天然分(fen)布范(fan)圍。而(er)華(hua)北等(deng)地的(de)(de)(de)闊葉林和(he)針(zhen)闊混(hun)交林中分(fen)布更為廣泛(fan)的(de)(de)(de)松(song)鼠(shu)是巖(yan)松(song)鼠(shu)。巖(yan)松(song)鼠(shu)體型(xing)較歐亞(ya)紅松(song)鼠(shu)小，耳朵上(shang)不具(ju)有長毛(mao)簇，色偏灰黃(huang)，更多(duo)地會(hui)下到(dao)地面上(shang)活(huo)動，尤其在(zai)(zai)多(duo)巖(yan)地帶(dai)，因(yin)此得名(ming)。而(er)花(hua)鼠(shu)也(ye)是中國(guo)(guo)溫帶(dai)地區常(chang)見的(de)(de)(de)松(song)鼠(shu)。這種背部長有黑白相間(jian)縱紋的(de)(de)(de)小動物會(hui)花(hua)更多(duo)的(de)(de)(de)時間(jian)在(zai)(zai)地面覓食，并常(chang)捕食小動物，還嗜啃食樹(shu)皮。赤(chi)腹松(song)鼠(shu)甚為膽大(da)，且可適應受到(dao)干(gan)擾的(de)(de)(de)林緣生(sheng)境，因(yin)此也(ye)能(neng)很好地生(sheng)活(huo)在(zai)(zai)城(cheng)(cheng)市公(gong)園綠(lv)地中。在(zai)(zai)上(shang)海、廣州(zhou)、成(cheng)都和(he)昆明等(deng)大(da)城(cheng)(cheng)市的(de)(de)(de)城(cheng)(cheng)市公(gong)園及周(zhou)邊(bian)地區都生(sheng)存著赤(chi)腹松(song)鼠(shu)，也(ye)是中國(guo)(guo)南方城(cheng)(cheng)市居民最易(yi)見到(dao)的(de)(de)(de)野生(sheng)哺乳動物。

生活習性

松(song)(song)鼠全年活動(dong)(dong)(dong)(dong)(dong)，不冬眠，為日(ri)行性動(dong)(dong)(dong)(dong)(dong)物，每日(ri)開(kai)始活動(dong)(dong)(dong)(dong)(dong)時(shi)間(jian)(jian)與(yu)日(ri)出時(shi)間(jian)(jian)有關(guan)，而(er)結束活動(dong)(dong)(dong)(dong)(dong)時(shi)間(jian)(jian)與(yu)日(ri)落時(shi)間(jian)(jian)無明顯關(guan)聯(lian)。松(song)(song)鼠的(de)日(ri)活動(dong)(dong)(dong)(dong)(dong)節律受氣(qi)候條(tiao)件的(de)影響(xiang)，大風、暴雨和嚴(yan)寒酷(ku)暑都會減少松(song)(song)鼠的(de)活動(dong)(dong)(dong)(dong)(dong)時(shi)間(jian)(jian)。覓食(shi)需(xu)要和留(liu)(liu)在巢(chao)(chao)中保存能量的(de)權衡(tradeoff)影響(xiang)著松(song)(song)鼠冬季的(de)活動(dong)(dong)(dong)(dong)(dong)格局(ju)。冬季日(ri)活動(dong)(dong)(dong)(dong)(dong)節律呈單(dan)峰型，在嚴(yan)寒天氣(qi)條(tiao)件下也會留(liu)(liu)在巢(chao)(chao)中幾天不活動(dong)(dong)(dong)(dong)(dong)。夏季則在上午(wu)和下午(wu)各出現一個活動(dong)(dong)(dong)(dong)(dong)高峰,。春季和秋季的(de)日(ri)活動(dong)(dong)(dong)(dong)(dong)格局(ju)介于冬、夏之間(jian)(jian)。

松鼠70%～80%的(de)時間(jian)都用于(yu)覓(mi)食(shi)(shi)活動，傾向于(yu)在針葉(xie)林中(zhong)覓(mi)食(shi)(shi)和貯(zhu)(zhu)食(shi)(shi)。秋季松鼠將(jiang)堅(jian)果(guo)分(fen)散貯(zhu)(zhu)藏(zang)于(yu)地(di)面，將(jiang)真(zhen)菌(jun)貯(zhu)(zhu)藏(zang)于(yu)樹枝上。秋季貯(zhu)(zhu)食(shi)(shi)有利于(yu)松鼠越冬(dong)和第二(er)年的(de)生育。松鼠貯(zhu)(zhu)食(shi)(shi)微生境選擇及貯(zhu)(zhu)食(shi)(shi)重(zhong)取(qu)機制得到了深入的(de)研究，成為當(dang)前(qian)國內(nei)松鼠生態學研究的(de)熱點。

松(song)鼠(shu)大(da)部分(fen)(fen)時間(jian)(jian)獨居。社(she)群結構建立在同(tong)性(xing)間(jian)(jian)和兩性(xing)間(jian)(jian)的(de)優勢序列基礎上(shang)，優勢個(ge)體(ti)體(ti)型通(tong)常較(jiao)其他(ta)個(ge)體(ti)大(da)。等(deng)級優勢通(tong)常僅在生殖季節(jie)才得(de)以(yi)(yi)體(ti)現(xian)。松(song)鼠(shu)會用尿液和下頜(he)腺的(de)分(fen)(fen)泌物(wu)在樹干(gan)和樹枝上(shang)涂抹(mo),以(yi)(yi)標記家域(homerange)。松(song)鼠(shu)的(de)家域大(da)小與生境質量、季節(jie)、性(xing)活動及食物(wu)豐度相關，不同(tong)分(fen)(fen)布區(qu)家域大(da)小差別很(hen)大(da)，但通(tong)常雄性(xing)家域大(da)于雌性(xing)，優勢個(ge)體(ti)家域大(da)于次(ci)級個(ge)體(ti)。在食物(wu)豐富(fu)的(de)地區(qu),家域會出現(xian)小范圍的(de)重疊。

松(song)鼠(shu)營(ying)巢居生活，也可(ke)以利(li)用樹(shu)(shu)洞和鳥巢。每個個體通常同(tong)時占有2～3個巢。由(you)于(yu)杉樹(shu)(shu)枝(zhi)葉(xie)相(xiang)對松(song)樹(shu)(shu)更為濃密，在人工林中(zhong)(zhong)，松(song)鼠(shu)通常選擇在杉樹(shu)(shu)上營(ying)巢。天(tian)然(ran)林中(zhong)(zhong)的巢址選擇問題(ti)未見報道(dao)。巢大部分(fen)(fen)營(ying)建在距地面8～16m的樹(shu)(shu)枝(zhi)上，靠近樹(shu)(shu)干或(huo)者位(wei)于(yu)樹(shu)(shu)枝(zhi)分(fen)(fen)叉處，分(fen)(fen)為日間使(shi)用的休息巢和夜(ye)間使(shi)用的睡眠巢兩種(zhong)類型(xing)，通常呈球形，直(zhi)徑(jing)約30cm，外(wai)層(ceng)由(you)細枝(zhi)、松(song)針和樹(shu)(shu)葉(xie)筑(zhu)成(cheng)(cheng)，內徑(jing)約12～16cm，覆以苔蘚、樹(shu)(shu)葉(xie)、松(song)針、干草(cao)和枝(zhi)皮(pi)等(deng)柔軟的材料(liao)。冬季(ji)(ji)松(song)鼠(shu)巢內形成(cheng)(cheng)一(yi)個微(wei)氣候環境，溫度(du)能高出巢外(wai)20～30°C，從而(er)減(jian)少了機體體溫調節所消耗的能量，減(jian)少了暴露在巢外(wai)低(di)溫、大風中(zhong)(zhong)的時間，這是生活于(yu)北(bei)溫帶地區的松(song)鼠(shu)冬季(ji)(ji)生存策略之一(yi)。在寒冷的冬季(ji)(ji),也會出現幾只松(song)鼠(shu)分(fen)(fen)享(xiang)同(tong)一(yi)個巢以維持體溫的現象。

松鼠沒有(you)明顯的遷徙，但有(you)短(duan)距離(li)的擴(kuo)(kuo)散行(xing)為，包括由越冬(dong)地(di)向(xiang)外的擴(kuo)(kuo)散和(he)由出生地(di)向(xiang)外的擴(kuo)(kuo)散。本地(di)競(jing)爭(zheng)決定(ding)了種群松鼠生態學(xue)研(yan)究現狀與(yu)展(zhan)望(wang)擴(kuo)(kuo)散距離(li)。研(yan)究表明，不同性(xing)(xing)(xing)(xing)別在擴(kuo)(kuo)散季節上存在差異，大部分雄(xiong)性(xing)(xing)(xing)(xing)個(ge)體在春季擴(kuo)(kuo)散，而雌性(xing)(xing)(xing)(xing)通常在秋季擴(kuo)(kuo)散。雌性(xing)(xing)(xing)(xing)個(ge)體的擴(kuo)(kuo)散受(shou)食物的影響，雄(xiong)性(xing)(xing)(xing)(xing)的擴(kuo)(kuo)散則(ze)取決于雌性(xing)(xing)(xing)(xing)的分布。

繁殖方式

松鼠的(de)生殖狀(zhuang)態與(yu)食(shi)物(wu)(wu)獲(huo)取(qu)狀(zhuang)況密切(qie)相(xiang)關。每(mei)年可(ke)以有(you)兩次生育，分別在(zai)2、3月和7、8月交配，妊娠期約為(wei)38～39d。但如果食(shi)物(wu)(wu)獲(huo)取(qu)不足，則春(chun)季交配會(hui)被(bei)推遲(chi)或消失。婚配制度是(shi)一(yi)雄多雌制或混(hun)交制。交配前有(you)求偶行為(wei)，通常(chang)優勢雄鼠會(hui)擁有(you)更多的(de)交配機會(hui)。初(chu)生雌鼠通常(chang)第(di)二年開始生育，其生殖能力與(yu)體(ti)重(zhong)(zhong)密切(qie)相(xiang)關，只有(you)超過(guo)一(yi)定體(ti)重(zhong)(zhong)閾的(de)雌性松鼠才具備生育能力，而且體(ti)重(zhong)(zhong)越大能夠生育的(de)后代越多。幼仔(zi)由雌鼠單(dan)獨哺(bu)育，哺(bu)乳期超過(guo)10周。