該圖片由注冊用戶""提供， 反饋已(yi)知最(zui)(zui)早的(de)(de)(de)松(song)(song)(song)鼠(shu)(shu)(shu)(shu)類物(wu)(wu)種(zhong)(zhong)(zhong)(zhong)的(de)(de)(de)化石(shi)(shi)來自始(shi)新世的(de)(de)(de)地(di)層。那是(shi)距今6500萬(wan)年～3500萬(wan)年前的(de)(de)(de)久(jiu)遠時(shi)代。那時(shi)恐龍剛剛滅絕不(bu)久(jiu)，哺(bu)乳動(dong)物(wu)(wu)尚未在(zai)(zai)陸(lu)(lu)地(di)上取得控制權(quan)，青藏(zang)高原尚未成為陸(lu)(lu)地(di)，歐洲(zhou)(zhou)和北美(mei)洲(zhou)(zhou)仍然有陸(lu)(lu)地(di)相連，南美(mei)洲(zhou)(zhou)則是(shi)一(yi)(yi)個巨大(da)(da)的(de)(de)(de)島嶼。最(zui)(zui)原始(shi)的(de)(de)(de)松(song)(song)(song)鼠(shu)(shu)(shu)(shu)生活(huo)在(zai)(zai)北美(mei)洲(zhou)(zhou)，形(xing)態與(yu)今天的(de)(de)(de)鼯(wu)鼠(shu)(shu)(shu)(shu)接近。在(zai)(zai)北美(mei)洲(zhou)(zhou)晚始(shi)新世的(de)(de)(de)地(di)層中(zhong)還發現了一(yi)(yi)系(xi)列松(song)(song)(song)鼠(shu)(shu)(shu)(shu)類物(wu)(wu)種(zhong)(zhong)(zhong)(zhong)的(de)(de)(de)化石(shi)(shi)，不(bu)同(tong)于(yu)現在(zai)(zai)的(de)(de)(de)任何一(yi)(yi)類松(song)(song)(song)鼠(shu)(shu)(shu)(shu)。北美(mei)洲(zhou)(zhou)異常(chang)豐富的(de)(de)(de)化石(shi)(shi)松(song)(song)(song)鼠(shu)(shu)(shu)(shu)種(zhong)(zhong)(zhong)(zhong)類顯示，松(song)(song)(song)鼠(shu)(shu)(shu)(shu)科(ke)起源(yuan)于(yu)始(shi)新世的(de)(de)(de)北美(mei)洲(zhou)(zhou)，并在(zai)(zai)之后的(de)(de)(de)漫長歲月中(zhong)輻射到了大(da)(da)洋洲(zhou)(zhou)以外的(de)(de)(de)各(ge)大(da)(da)洲(zhou)(zhou)，在(zai)(zai)這個過程中(zhong)演化出了形(xing)態各(ge)異、適應各(ge)種(zhong)(zhong)(zhong)(zhong)環(huan)境(jing)的(de)(de)(de)物(wu)(wu)種(zhong)(zhong)(zhong)(zhong)。在(zai)(zai)現存(cun)的(de)(de)(de)嚙(nie)齒目松(song)(song)(song)鼠(shu)(shu)(shu)(shu)亞(ya)目物(wu)(wu)種(zhong)(zhong)(zhong)(zhong)中(zhong)，主要分布于(yu)歐亞(ya)大(da)(da)陸(lu)(lu)的(de)(de)(de)睡鼠(shu)(shu)(shu)(shu)科(ke)和分布于(yu)北美(mei)洲(zhou)(zhou)的(de)(de)(de)山河貍科(ke)與(yu)松(song)(song)(song)鼠(shu)(shu)(shu)(shu)科(ke)有較近的(de)(de)(de)親緣關系(xi)。而(er)松(song)(song)(song)鼠(shu)(shu)(shu)(shu)科(ke)是(shi)最(zui)(zui)為人熟(shu)知的(de)(de)(de)松(song)(song)(song)鼠(shu)(shu)(shu)(shu)家(jia)族(zu)成員，也是(shi)分布最(zui)(zui)廣、種(zhong)(zhong)(zhong)(zhong)類最(zui)(zui)繁多的(de)(de)(de)一(yi)(yi)個類群。
廣(guang)布于古北(bei)(bei)(bei)界溫帶(dai)和(he)寒溫帶(dai)森(sen)林生態系(xi)統(tong)中(zhong)，西起伊比利(li)亞(ya)和(he)大(da)不列顛島，東至堪察加半島、俄羅斯薩(sa)哈林島和(he)日(ri)本(ben)的(de)北(bei)(bei)(bei)海道，南(nan)至地(di)中(zhong)海、黑海、蒙古北(bei)(bei)(bei)部、中(zhong)國的(de)西北(bei)(bei)(bei)和(he)東北(bei)(bei)(bei)地(di)區。
松(song)鼠(shu)主(zhu)要分布(bu)在由(you)松(song)屬(Pinus)、落葉松(song)屬(Larix)和云杉屬(Picea)樹種構成的(de)針(zhen)葉林(lin)或針(zhen)闊混(hun)交林(lin)中(zhong)。由(you)于(yu)食物來源(yuan)相對(dui)較(jiao)為豐(feng)富和穩定，松(song)鼠(shu)在針(zhen)闊混(hun)交林(lin)中(zhong)可以(yi)維持較(jiao)高(gao)的(de)種群密(mi)度，并可以(yi)利用城(cheng)郊甚(shen)至(zhi)城(cheng)市中(zhong)的(de)小片林(lin)地，成為伴人(ren)動(dong)物。
歐(ou)(ou)亞(ya)(ya)(ya)(ya)大(da)陸(lu)(lu)北(bei)(bei)(bei)部溫帶針葉林(lin)帶廣(guang)泛(fan)分布的(de)(de)(de)歐(ou)(ou)亞(ya)(ya)(ya)(ya)紅松(song)(song)(song)鼠(shu)（也(ye)稱北(bei)(bei)(bei)松(song)(song)(song)鼠(shu)）是松(song)(song)(song)鼠(shu)的(de)(de)(de)典型代表(biao)，也(ye)是大(da)眾熟知的(de)(de)(de)松(song)(song)(song)鼠(shu)形象的(de)(de)(de)原型。分布在歐(ou)(ou)亞(ya)(ya)(ya)(ya)大(da)陸(lu)(lu)東端(duan)的(de)(de)(de)歐(ou)(ou)亞(ya)(ya)(ya)(ya)紅松(song)(song)(song)鼠(shu)冬季背(bei)毛(mao)黑而腹白，夏毛(mao)灰間棕紅色(se)(se)；而分布在歐(ou)(ou)亞(ya)(ya)(ya)(ya)大(da)陸(lu)(lu)西端(duan)的(de)(de)(de)歐(ou)(ou)亞(ya)(ya)(ya)(ya)紅松(song)(song)(song)鼠(shu)背(bei)毛(mao)全年均為棕紅色(se)(se)。灰間棕紅色(se)(se)也(ye)是北(bei)(bei)(bei)美(mei)洲森(sen)林(lin)中多數松(song)(song)(song)鼠(shu)的(de)(de)(de)主要色(se)(se)調(diao)。歐(ou)(ou)亞(ya)(ya)(ya)(ya)紅松(song)(song)(song)鼠(shu)在分布范圍內(nei)從(cong)東至西不(bu)同地(di)理群體毛(mao)色(se)(se)的(de)(de)(de)變化也(ye)是歷史(shi)上(shang)松(song)(song)(song)鼠(shu)從(cong)北(bei)(bei)(bei)美(mei)大(da)陸(lu)(lu)起源，輻射進入歐(ou)(ou)亞(ya)(ya)(ya)(ya)大(da)陸(lu)(lu)這一過(guo)程的(de)(de)(de)反映。
在(zai)中國(guo)，東北(bei)地(di)(di)(di)區和(he)新疆的(de)(de)泰加林(lin)(lin)是歐(ou)(ou)亞紅松(song)(song)鼠(shu)(shu)的(de)(de)天然分布(bu)范圍(wei)。而華北(bei)等(deng)地(di)(di)(di)的(de)(de)闊(kuo)葉林(lin)(lin)和(he)針闊(kuo)混交林(lin)(lin)中分布(bu)更(geng)為廣(guang)泛的(de)(de)松(song)(song)鼠(shu)(shu)是巖(yan)松(song)(song)鼠(shu)(shu)。巖(yan)松(song)(song)鼠(shu)(shu)體(ti)型較歐(ou)(ou)亞紅松(song)(song)鼠(shu)(shu)小，耳(er)朵上(shang)不具有(you)長(chang)毛簇(cu)，色偏灰(hui)黃，更(geng)多(duo)地(di)(di)(di)會(hui)下(xia)到(dao)地(di)(di)(di)面上(shang)活動(dong)，尤其在(zai)多(duo)巖(yan)地(di)(di)(di)帶，因(yin)此得名。而花(hua)鼠(shu)(shu)也是中國(guo)溫帶地(di)(di)(di)區常(chang)見(jian)的(de)(de)松(song)(song)鼠(shu)(shu)。這(zhe)種背部長(chang)有(you)黑白相間(jian)縱(zong)紋的(de)(de)小動(dong)物(wu)(wu)會(hui)花(hua)更(geng)多(duo)的(de)(de)時間(jian)在(zai)地(di)(di)(di)面覓食(shi)(shi)，并(bing)常(chang)捕食(shi)(shi)小動(dong)物(wu)(wu)，還嗜啃(ken)食(shi)(shi)樹皮。赤腹松(song)(song)鼠(shu)(shu)甚為膽大，且(qie)可適應受到(dao)干擾的(de)(de)林(lin)(lin)緣生(sheng)(sheng)境(jing)，因(yin)此也能很(hen)好(hao)地(di)(di)(di)生(sheng)(sheng)活在(zai)城(cheng)(cheng)市(shi)(shi)公園綠(lv)地(di)(di)(di)中。在(zai)上(shang)海、廣(guang)州(zhou)、成都(dou)和(he)昆(kun)明等(deng)大城(cheng)(cheng)市(shi)(shi)的(de)(de)城(cheng)(cheng)市(shi)(shi)公園及周邊地(di)(di)(di)區都(dou)生(sheng)(sheng)存著赤腹松(song)(song)鼠(shu)(shu)，也是中國(guo)南方城(cheng)(cheng)市(shi)(shi)居民最易見(jian)到(dao)的(de)(de)野(ye)生(sheng)(sheng)哺乳動(dong)物(wu)(wu)。
松(song)鼠全年活(huo)動(dong)(dong)(dong)，不冬眠，為日(ri)行性(xing)動(dong)(dong)(dong)物，每日(ri)開始活(huo)動(dong)(dong)(dong)時(shi)間(jian)(jian)與日(ri)出時(shi)間(jian)(jian)有(you)關，而結束活(huo)動(dong)(dong)(dong)時(shi)間(jian)(jian)與日(ri)落時(shi)間(jian)(jian)無明顯關聯。松(song)鼠的(de)(de)(de)日(ri)活(huo)動(dong)(dong)(dong)節(jie)律(lv)受(shou)氣(qi)候條(tiao)件的(de)(de)(de)影響(xiang)，大(da)風、暴雨和(he)嚴(yan)寒酷暑都會減少松(song)鼠的(de)(de)(de)活(huo)動(dong)(dong)(dong)時(shi)間(jian)(jian)。覓(mi)食需要和(he)留在巢中(zhong)保(bao)存能(neng)量的(de)(de)(de)權衡(tradeoff)影響(xiang)著松(song)鼠冬季(ji)的(de)(de)(de)活(huo)動(dong)(dong)(dong)格局。冬季(ji)日(ri)活(huo)動(dong)(dong)(dong)節(jie)律(lv)呈單峰型，在嚴(yan)寒天氣(qi)條(tiao)件下也會留在巢中(zhong)幾天不活(huo)動(dong)(dong)(dong)。夏季(ji)則在上(shang)午和(he)下午各(ge)出現一個活(huo)動(dong)(dong)(dong)高峰,。春季(ji)和(he)秋季(ji)的(de)(de)(de)日(ri)活(huo)動(dong)(dong)(dong)格局介于冬、夏之(zhi)間(jian)(jian)。
松(song)(song)鼠(shu)(shu)70%～80%的(de)(de)時間都用于(yu)(yu)覓食活(huo)動，傾向(xiang)于(yu)(yu)在(zai)針(zhen)葉林中覓食和貯(zhu)(zhu)食。秋(qiu)季松(song)(song)鼠(shu)(shu)將堅果(guo)分(fen)散貯(zhu)(zhu)藏(zang)于(yu)(yu)地面，將真菌貯(zhu)(zhu)藏(zang)于(yu)(yu)樹枝上。秋(qiu)季貯(zhu)(zhu)食有(you)利于(yu)(yu)松(song)(song)鼠(shu)(shu)越(yue)冬和第(di)二(er)年的(de)(de)生育。松(song)(song)鼠(shu)(shu)貯(zhu)(zhu)食微(wei)生境選擇及貯(zhu)(zhu)食重取(qu)機制得到了深(shen)入(ru)的(de)(de)研(yan)(yan)究，成為當(dang)前(qian)國內松(song)(song)鼠(shu)(shu)生態(tai)學(xue)研(yan)(yan)究的(de)(de)熱點。
松鼠(shu)大部(bu)分時間獨居。社群結(jie)構建立在同性(xing)(xing)間和(he)兩性(xing)(xing)間的優勢序(xu)列(lie)基(ji)礎上，優勢個(ge)(ge)體(ti)(ti)體(ti)(ti)型通常較(jiao)其(qi)他個(ge)(ge)體(ti)(ti)大。等級(ji)優勢通常僅在生(sheng)殖季節才(cai)得以(yi)體(ti)(ti)現。松鼠(shu)會用尿(niao)液(ye)和(he)下頜(he)腺的分泌物(wu)在樹干和(he)樹枝上涂抹(mo),以(yi)標記家域(yu)(homerange)。松鼠(shu)的家域(yu)大小(xiao)與生(sheng)境質量(liang)、季節、性(xing)(xing)活動及食(shi)物(wu)豐度相關，不同分布區家域(yu)大小(xiao)差別(bie)很(hen)大，但通常雄性(xing)(xing)家域(yu)大于雌(ci)性(xing)(xing)，優勢個(ge)(ge)體(ti)(ti)家域(yu)大于次級(ji)個(ge)(ge)體(ti)(ti)。在食(shi)物(wu)豐富(fu)的地區,家域(yu)會出現小(xiao)范(fan)圍的重疊。
松(song)鼠(shu)營(ying)巢居生活，也可以(yi)利用樹(shu)(shu)洞和(he)鳥巢。每個個體通(tong)常同(tong)時占有2～3個巢。由于杉(shan)樹(shu)(shu)枝(zhi)葉(xie)相對松(song)樹(shu)(shu)更為(wei)(wei)濃密，在人工林中，松(song)鼠(shu)通(tong)常選擇(ze)在杉(shan)樹(shu)(shu)上營(ying)巢。天然(ran)林中的(de)(de)巢址選擇(ze)問題未見報道(dao)。巢大部分營(ying)建(jian)在距地(di)(di)面(mian)8～16m的(de)(de)樹(shu)(shu)枝(zhi)上，靠(kao)近樹(shu)(shu)干或者位于樹(shu)(shu)枝(zhi)分叉(cha)處，分為(wei)(wei)日間使(shi)用的(de)(de)休息巢和(he)夜間使(shi)用的(de)(de)睡眠巢兩種類型，通(tong)常呈球(qiu)形，直(zhi)徑(jing)約30cm，外(wai)(wai)層由細枝(zhi)、松(song)針和(he)樹(shu)(shu)葉(xie)筑(zhu)成，內(nei)徑(jing)約12～16cm，覆以(yi)苔(tai)蘚、樹(shu)(shu)葉(xie)、松(song)針、干草和(he)枝(zhi)皮(pi)等柔軟的(de)(de)材(cai)料。冬季松(song)鼠(shu)巢內(nei)形成一(yi)個微氣候環(huan)境，溫(wen)(wen)度能(neng)高(gao)出巢外(wai)(wai)20～30°C，從而減少了機體體溫(wen)(wen)調節所(suo)消耗的(de)(de)能(neng)量，減少了暴(bao)露(lu)在巢外(wai)(wai)低溫(wen)(wen)、大風(feng)中的(de)(de)時間，這是生活于北(bei)溫(wen)(wen)帶地(di)(di)區(qu)的(de)(de)松(song)鼠(shu)冬季生存策略之一(yi)。在寒冷(leng)的(de)(de)冬季,也會出現(xian)幾只松(song)鼠(shu)分享同(tong)一(yi)個巢以(yi)維持體溫(wen)(wen)的(de)(de)現(xian)象。
松鼠(shu)沒有明(ming)(ming)顯的(de)(de)遷徙，但有短(duan)距離(li)的(de)(de)擴(kuo)(kuo)散(san)(san)(san)行為(wei)，包括由越冬地(di)向(xiang)外的(de)(de)擴(kuo)(kuo)散(san)(san)(san)和由出生地(di)向(xiang)外的(de)(de)擴(kuo)(kuo)散(san)(san)(san)。本地(di)競爭決(jue)定了種(zhong)群松鼠(shu)生態(tai)學(xue)研究現狀(zhuang)與(yu)展望(wang)擴(kuo)(kuo)散(san)(san)(san)距離(li)。研究表明(ming)(ming)，不同性別在(zai)擴(kuo)(kuo)散(san)(san)(san)季(ji)節(jie)上(shang)存在(zai)差(cha)異，大部分雄性個(ge)體在(zai)春季(ji)擴(kuo)(kuo)散(san)(san)(san)，而雌性通常在(zai)秋季(ji)擴(kuo)(kuo)散(san)(san)(san)。雌性個(ge)體的(de)(de)擴(kuo)(kuo)散(san)(san)(san)受(shou)食(shi)物的(de)(de)影響，雄性的(de)(de)擴(kuo)(kuo)散(san)(san)(san)則(ze)取決(jue)于雌性的(de)(de)分布。
松鼠(shu)(shu)的(de)生殖(zhi)狀(zhuang)態與食(shi)物獲取(qu)狀(zhuang)況密(mi)切(qie)相(xiang)關。每年(nian)可(ke)以有兩次生育(yu)(yu)(yu)，分別(bie)在2、3月和7、8月交配(pei)，妊娠期(qi)約為38～39d。但(dan)如果食(shi)物獲取(qu)不(bu)足，則春季交配(pei)會(hui)被推遲或消失。婚配(pei)制(zhi)度是一(yi)雄多雌制(zhi)或混交制(zhi)。交配(pei)前有求偶行為，通常(chang)優(you)勢(shi)雄鼠(shu)(shu)會(hui)擁有更多的(de)交配(pei)機(ji)會(hui)。初生雌鼠(shu)(shu)通常(chang)第二年(nian)開始生育(yu)(yu)(yu)，其生殖(zhi)能(neng)力(li)與體重密(mi)切(qie)相(xiang)關，只(zhi)有超過一(yi)定體重閾的(de)雌性(xing)松鼠(shu)(shu)才(cai)具備生育(yu)(yu)(yu)能(neng)力(li)，而且(qie)體重越大(da)能(neng)夠生育(yu)(yu)(yu)的(de)后代越多。幼仔由雌鼠(shu)(shu)單獨哺育(yu)(yu)(yu)，哺乳期(qi)超過10周(zhou)。
