該圖片由注冊用戶""提供， 反饋已知最(zui)早的(de)松(song)(song)(song)鼠(shu)(shu)(shu)類(lei)(lei)物(wu)(wu)(wu)種(zhong)的(de)化(hua)(hua)石(shi)(shi)來自始新世(shi)的(de)地層。那(nei)是(shi)距今6500萬年(nian)(nian)～3500萬年(nian)(nian)前的(de)久遠時(shi)代。那(nei)時(shi)恐龍剛剛滅絕不久，哺乳(ru)動物(wu)(wu)(wu)尚未(wei)在(zai)(zai)(zai)陸(lu)地上取得(de)控(kong)制權，青(qing)藏高原尚未(wei)成為陸(lu)地，歐洲(zhou)(zhou)(zhou)和(he)北(bei)(bei)美洲(zhou)(zhou)(zhou)仍然有(you)(you)陸(lu)地相連，南美洲(zhou)(zhou)(zhou)則是(shi)一個(ge)(ge)巨大(da)的(de)島嶼。最(zui)原始的(de)松(song)(song)(song)鼠(shu)(shu)(shu)生活在(zai)(zai)(zai)北(bei)(bei)美洲(zhou)(zhou)(zhou)，形(xing)態與今天的(de)鼯鼠(shu)(shu)(shu)接近。在(zai)(zai)(zai)北(bei)(bei)美洲(zhou)(zhou)(zhou)晚始新世(shi)的(de)地層中還發現了一系列(lie)松(song)(song)(song)鼠(shu)(shu)(shu)類(lei)(lei)物(wu)(wu)(wu)種(zhong)的(de)化(hua)(hua)石(shi)(shi)，不同(tong)于(yu)(yu)現在(zai)(zai)(zai)的(de)任何一類(lei)(lei)松(song)(song)(song)鼠(shu)(shu)(shu)。北(bei)(bei)美洲(zhou)(zhou)(zhou)異常(chang)豐富(fu)的(de)化(hua)(hua)石(shi)(shi)松(song)(song)(song)鼠(shu)(shu)(shu)種(zhong)類(lei)(lei)顯(xian)示，松(song)(song)(song)鼠(shu)(shu)(shu)科(ke)(ke)(ke)起源于(yu)(yu)始新世(shi)的(de)北(bei)(bei)美洲(zhou)(zhou)(zhou)，并在(zai)(zai)(zai)之后的(de)漫(man)長(chang)歲月中輻(fu)射到了大(da)洋洲(zhou)(zhou)(zhou)以(yi)外的(de)各(ge)大(da)洲(zhou)(zhou)(zhou)，在(zai)(zai)(zai)這個(ge)(ge)過程中演(yan)化(hua)(hua)出了形(xing)態各(ge)異、適應各(ge)種(zhong)環境的(de)物(wu)(wu)(wu)種(zhong)。在(zai)(zai)(zai)現存的(de)嚙(nie)齒(chi)目松(song)(song)(song)鼠(shu)(shu)(shu)亞(ya)目物(wu)(wu)(wu)種(zhong)中，主要分(fen)布于(yu)(yu)歐亞(ya)大(da)陸(lu)的(de)睡鼠(shu)(shu)(shu)科(ke)(ke)(ke)和(he)分(fen)布于(yu)(yu)北(bei)(bei)美洲(zhou)(zhou)(zhou)的(de)山河貍(li)科(ke)(ke)(ke)與松(song)(song)(song)鼠(shu)(shu)(shu)科(ke)(ke)(ke)有(you)(you)較(jiao)近的(de)親緣關系。而(er)松(song)(song)(song)鼠(shu)(shu)(shu)科(ke)(ke)(ke)是(shi)最(zui)為人熟知的(de)松(song)(song)(song)鼠(shu)(shu)(shu)家族成員，也是(shi)分(fen)布最(zui)廣、種(zhong)類(lei)(lei)最(zui)繁多的(de)一個(ge)(ge)類(lei)(lei)群。
廣(guang)布(bu)于(yu)古(gu)北(bei)(bei)(bei)界(jie)溫帶和寒(han)溫帶森林生態系統中(zhong)，西起伊(yi)比利亞和大不列顛島，東至堪(kan)察加半島、俄羅斯(si)薩哈林島和日(ri)本的(de)(de)北(bei)(bei)(bei)海(hai)道，南至地(di)中(zhong)海(hai)、黑海(hai)、蒙古(gu)北(bei)(bei)(bei)部、中(zhong)國的(de)(de)西北(bei)(bei)(bei)和東北(bei)(bei)(bei)地(di)區。
松鼠主要分布在(zai)(zai)由松屬(Pinus)、落葉松屬(Larix)和云(yun)杉屬(Picea)樹種(zhong)構(gou)成的(de)針葉林(lin)或針闊混交林(lin)中(zhong)。由于食物(wu)來源相(xiang)對(dui)較為豐富和穩定，松鼠在(zai)(zai)針闊混交林(lin)中(zhong)可以維(wei)持較高的(de)種(zhong)群密度，并可以利(li)用城郊(jiao)甚至(zhi)城市中(zhong)的(de)小片林(lin)地，成為伴人(ren)動物(wu)。
歐亞(ya)(ya)(ya)大(da)陸(lu)北部溫帶(dai)(dai)針葉林(lin)帶(dai)(dai)廣泛(fan)分(fen)(fen)布的(de)歐亞(ya)(ya)(ya)紅(hong)松(song)鼠(shu)(shu)(shu)（也(ye)稱北松(song)鼠(shu)(shu)(shu)）是(shi)松(song)鼠(shu)(shu)(shu)的(de)典型代表，也(ye)是(shi)大(da)眾熟知的(de)松(song)鼠(shu)(shu)(shu)形(xing)象的(de)原型。分(fen)(fen)布在(zai)歐亞(ya)(ya)(ya)大(da)陸(lu)東端(duan)的(de)歐亞(ya)(ya)(ya)紅(hong)松(song)鼠(shu)(shu)(shu)冬季(ji)背毛(mao)(mao)黑而(er)腹白，夏(xia)毛(mao)(mao)灰間棕紅(hong)色(se)；而(er)分(fen)(fen)布在(zai)歐亞(ya)(ya)(ya)大(da)陸(lu)西端(duan)的(de)歐亞(ya)(ya)(ya)紅(hong)松(song)鼠(shu)(shu)(shu)背毛(mao)(mao)全年均為棕紅(hong)色(se)。灰間棕紅(hong)色(se)也(ye)是(shi)北美洲森(sen)林(lin)中多數松(song)鼠(shu)(shu)(shu)的(de)主要色(se)調(diao)。歐亞(ya)(ya)(ya)紅(hong)松(song)鼠(shu)(shu)(shu)在(zai)分(fen)(fen)布范圍(wei)內從東至西不同地理群體毛(mao)(mao)色(se)的(de)變化(hua)也(ye)是(shi)歷史上松(song)鼠(shu)(shu)(shu)從北美大(da)陸(lu)起源，輻射進入(ru)歐亞(ya)(ya)(ya)大(da)陸(lu)這一過程的(de)反映。
在(zai)中(zhong)國(guo)，東北地(di)(di)區(qu)和新疆的(de)(de)泰加(jia)林是(shi)(shi)歐(ou)亞紅(hong)(hong)松(song)(song)(song)鼠(shu)(shu)的(de)(de)天(tian)然分布(bu)(bu)范圍。而(er)華北等地(di)(di)的(de)(de)闊(kuo)葉林和針(zhen)闊(kuo)混交林中(zhong)分布(bu)(bu)更為(wei)廣泛的(de)(de)松(song)(song)(song)鼠(shu)(shu)是(shi)(shi)巖(yan)松(song)(song)(song)鼠(shu)(shu)。巖(yan)松(song)(song)(song)鼠(shu)(shu)體(ti)型(xing)較歐(ou)亞紅(hong)(hong)松(song)(song)(song)鼠(shu)(shu)小，耳(er)朵上不具(ju)有長毛簇(cu)，色(se)偏灰(hui)黃，更多地(di)(di)會下到地(di)(di)面(mian)上活動，尤其在(zai)多巖(yan)地(di)(di)帶，因(yin)此得名。而(er)花(hua)鼠(shu)(shu)也(ye)(ye)是(shi)(shi)中(zhong)國(guo)溫(wen)帶地(di)(di)區(qu)常見的(de)(de)松(song)(song)(song)鼠(shu)(shu)。這(zhe)種背部長有黑白(bai)相間(jian)縱紋的(de)(de)小動物(wu)會花(hua)更多的(de)(de)時間(jian)在(zai)地(di)(di)面(mian)覓(mi)食(shi)，并(bing)常捕食(shi)小動物(wu)，還嗜啃食(shi)樹皮。赤腹(fu)松(song)(song)(song)鼠(shu)(shu)甚為(wei)膽大，且(qie)可適應(ying)受到干擾的(de)(de)林緣生(sheng)境，因(yin)此也(ye)(ye)能很好地(di)(di)生(sheng)活在(zai)城(cheng)(cheng)市公園綠(lv)地(di)(di)中(zhong)。在(zai)上海(hai)、廣州、成都(dou)和昆明等大城(cheng)(cheng)市的(de)(de)城(cheng)(cheng)市公園及周邊(bian)地(di)(di)區(qu)都(dou)生(sheng)存著赤腹(fu)松(song)(song)(song)鼠(shu)(shu)，也(ye)(ye)是(shi)(shi)中(zhong)國(guo)南方城(cheng)(cheng)市居民最(zui)易見到的(de)(de)野生(sheng)哺乳動物(wu)。
松(song)鼠(shu)全年(nian)活(huo)(huo)動(dong)(dong)，不冬(dong)眠，為(wei)日(ri)(ri)行性動(dong)(dong)物，每日(ri)(ri)開始(shi)活(huo)(huo)動(dong)(dong)時(shi)間(jian)(jian)與日(ri)(ri)出時(shi)間(jian)(jian)有關，而結束(shu)活(huo)(huo)動(dong)(dong)時(shi)間(jian)(jian)與日(ri)(ri)落時(shi)間(jian)(jian)無(wu)明顯關聯。松(song)鼠(shu)的(de)日(ri)(ri)活(huo)(huo)動(dong)(dong)節(jie)律受氣候條件的(de)影響，大風、暴雨和(he)(he)嚴寒酷暑都會減少(shao)松(song)鼠(shu)的(de)活(huo)(huo)動(dong)(dong)時(shi)間(jian)(jian)。覓食(shi)需(xu)要(yao)和(he)(he)留在巢(chao)中保(bao)存(cun)能量(liang)的(de)權衡(tradeoff)影響著松(song)鼠(shu)冬(dong)季的(de)活(huo)(huo)動(dong)(dong)格局。冬(dong)季日(ri)(ri)活(huo)(huo)動(dong)(dong)節(jie)律呈單峰型，在嚴寒天氣條件下(xia)也會留在巢(chao)中幾天不活(huo)(huo)動(dong)(dong)。夏季則在上(shang)午(wu)和(he)(he)下(xia)午(wu)各出現一個活(huo)(huo)動(dong)(dong)高峰,。春(chun)季和(he)(he)秋季的(de)日(ri)(ri)活(huo)(huo)動(dong)(dong)格局介于冬(dong)、夏之間(jian)(jian)。
松(song)(song)(song)鼠(shu)70%～80%的(de)時間都(dou)用于(yu)(yu)(yu)覓食(shi)(shi)活(huo)動，傾向(xiang)于(yu)(yu)(yu)在針葉林(lin)中覓食(shi)(shi)和貯(zhu)(zhu)食(shi)(shi)。秋(qiu)季(ji)松(song)(song)(song)鼠(shu)將堅果(guo)分散貯(zhu)(zhu)藏于(yu)(yu)(yu)地面，將真菌貯(zhu)(zhu)藏于(yu)(yu)(yu)樹枝上(shang)。秋(qiu)季(ji)貯(zhu)(zhu)食(shi)(shi)有利(li)于(yu)(yu)(yu)松(song)(song)(song)鼠(shu)越(yue)冬和第二(er)年(nian)的(de)生(sheng)育。松(song)(song)(song)鼠(shu)貯(zhu)(zhu)食(shi)(shi)微生(sheng)境(jing)選擇及(ji)貯(zhu)(zhu)食(shi)(shi)重取機(ji)制(zhi)得(de)到(dao)了深入的(de)研究，成為當前國內松(song)(song)(song)鼠(shu)生(sheng)態學研究的(de)熱點。
松(song)(song)鼠(shu)大(da)部(bu)分(fen)時間獨居。社群(qun)結構(gou)建(jian)立在(zai)同(tong)性間和(he)兩性間的(de)(de)優(you)勢序列基礎上，優(you)勢個體體型通常較其他個體大(da)。等級優(you)勢通常僅(jin)在(zai)生殖季節才得(de)以體現(xian)。松(song)(song)鼠(shu)會(hui)用尿(niao)液和(he)下頜腺的(de)(de)分(fen)泌物(wu)在(zai)樹干和(he)樹枝上涂抹,以標記家域(yu)(yu)(homerange)。松(song)(song)鼠(shu)的(de)(de)家域(yu)(yu)大(da)小與生境質(zhi)量(liang)、季節、性活動(dong)及食(shi)物(wu)豐度相關，不同(tong)分(fen)布區家域(yu)(yu)大(da)小差別很大(da)，但通常雄(xiong)性家域(yu)(yu)大(da)于雌性，優(you)勢個體家域(yu)(yu)大(da)于次(ci)級個體。在(zai)食(shi)物(wu)豐富的(de)(de)地(di)區,家域(yu)(yu)會(hui)出現(xian)小范圍的(de)(de)重疊。
松(song)(song)(song)(song)鼠營(ying)巢居生活，也可(ke)以(yi)利用樹洞和鳥巢。每個(ge)(ge)個(ge)(ge)體(ti)通(tong)常同時占有2～3個(ge)(ge)巢。由于杉樹枝(zhi)(zhi)葉(xie)相對(dui)松(song)(song)(song)(song)樹更(geng)為濃密，在人工林(lin)(lin)中(zhong)，松(song)(song)(song)(song)鼠通(tong)常選擇在杉樹上營(ying)巢。天然林(lin)(lin)中(zhong)的(de)(de)巢址選擇問題未見報(bao)道。巢大部分營(ying)建(jian)在距地面(mian)8～16m的(de)(de)樹枝(zhi)(zhi)上，靠近樹干(gan)或者位于樹枝(zhi)(zhi)分叉處，分為日(ri)間(jian)使(shi)(shi)用的(de)(de)休息巢和夜間(jian)使(shi)(shi)用的(de)(de)睡眠巢兩(liang)種(zhong)類型，通(tong)常呈球形(xing)，直徑約30cm，外(wai)層由細(xi)枝(zhi)(zhi)、松(song)(song)(song)(song)針和樹葉(xie)筑成(cheng)，內徑約12～16cm，覆以(yi)苔蘚、樹葉(xie)、松(song)(song)(song)(song)針、干(gan)草和枝(zhi)(zhi)皮等柔軟的(de)(de)材料。冬季(ji)松(song)(song)(song)(song)鼠巢內形(xing)成(cheng)一(yi)個(ge)(ge)微(wei)氣候環境，溫(wen)(wen)度能高出巢外(wai)20～30°C，從而減(jian)少了機體(ti)體(ti)溫(wen)(wen)調節所消耗的(de)(de)能量，減(jian)少了暴露在巢外(wai)低溫(wen)(wen)、大風中(zhong)的(de)(de)時間(jian)，這是生活于北溫(wen)(wen)帶地區的(de)(de)松(song)(song)(song)(song)鼠冬季(ji)生存策略(lve)之一(yi)。在寒冷的(de)(de)冬季(ji),也會(hui)出現(xian)幾只松(song)(song)(song)(song)鼠分享同一(yi)個(ge)(ge)巢以(yi)維(wei)持體(ti)溫(wen)(wen)的(de)(de)現(xian)象。
松鼠沒有明(ming)顯(xian)的遷徙，但有短距(ju)離的擴(kuo)(kuo)(kuo)散(san)行為(wei)，包括由(you)越冬地(di)向外的擴(kuo)(kuo)(kuo)散(san)和由(you)出生(sheng)地(di)向外的擴(kuo)(kuo)(kuo)散(san)。本地(di)競爭決定(ding)了種群松鼠生(sheng)態(tai)學研(yan)究(jiu)現狀(zhuang)與展望擴(kuo)(kuo)(kuo)散(san)距(ju)離。研(yan)究(jiu)表明(ming)，不同性別(bie)在(zai)(zai)擴(kuo)(kuo)(kuo)散(san)季(ji)節上(shang)存(cun)在(zai)(zai)差異(yi)，大部分雄性個體(ti)(ti)在(zai)(zai)春季(ji)擴(kuo)(kuo)(kuo)散(san)，而雌(ci)性通常在(zai)(zai)秋(qiu)季(ji)擴(kuo)(kuo)(kuo)散(san)。雌(ci)性個體(ti)(ti)的擴(kuo)(kuo)(kuo)散(san)受食(shi)物的影響，雄性的擴(kuo)(kuo)(kuo)散(san)則(ze)取決于雌(ci)性的分布。
松(song)鼠(shu)的生(sheng)殖狀(zhuang)態(tai)與(yu)食物獲取(qu)狀(zhuang)況密切相關。每年可以有兩次(ci)生(sheng)育(yu)，分別在2、3月(yue)和7、8月(yue)交(jiao)配(pei)(pei)，妊娠(shen)期約(yue)為38～39d。但如果食物獲取(qu)不足(zu)，則春季(ji)交(jiao)配(pei)(pei)會(hui)(hui)(hui)被推遲或消失。婚配(pei)(pei)制(zhi)度是一雄多雌(ci)制(zhi)或混交(jiao)制(zhi)。交(jiao)配(pei)(pei)前有求偶行(xing)為，通(tong)常(chang)優(you)勢(shi)雄鼠(shu)會(hui)(hui)(hui)擁有更多的交(jiao)配(pei)(pei)機會(hui)(hui)(hui)。初生(sheng)雌(ci)鼠(shu)通(tong)常(chang)第二年開始生(sheng)育(yu)，其生(sheng)殖能(neng)力與(yu)體重(zhong)(zhong)密切相關，只有超過一定體重(zhong)(zhong)閾的雌(ci)性松(song)鼠(shu)才具備(bei)生(sheng)育(yu)能(neng)力，而且體重(zhong)(zhong)越大能(neng)夠生(sheng)育(yu)的后代越多。幼仔由雌(ci)鼠(shu)單獨哺育(yu)，哺乳(ru)期超過10周。
