2022年7月29日晚，在中國(guó)古動(dòng)物館，中科院古脊椎動(dòng)物和古人類學(xué)研究所（IVPP）教授托馬斯·斯坦哈姆（Thomas A. Stidham）以“鳥類——會(huì)飛的神奇恐龍”為題，為小朋友們帶來了一場(chǎng)生動(dòng)的科普講座。他介紹了“鳥類是恐龍后裔”的多種證據(jù)，比如它們?nèi)绾握玖⑿凶?、相似的骨骼結(jié)構(gòu)和形狀、羽毛和蛋的特點(diǎn)，等等。

托馬斯來自美國(guó)，在中國(guó)已經(jīng)工作了10余年，是一位鳥類進(jìn)化和化石研究方面的知名專家。我們的采訪，就約在了中國(guó)古動(dòng)物館的一間教室。這家博物館并不大，主要陳列中國(guó)各地發(fā)現(xiàn)的脊椎動(dòng)物化石，比如帶羽恐龍、早期頜魚、生活在中國(guó)的第一批人類等，尤其是由中國(guó)人自主發(fā)現(xiàn)、發(fā)掘、研究的第一條恐龍——許氏祿豐龍，這些化石為我們展示了脊椎動(dòng)物的進(jìn)化歷程。教室四周的墻上掛滿了我國(guó)著名地質(zhì)學(xué)家和古生物學(xué)家楊鐘健的照片，他是我國(guó)古脊椎動(dòng)物學(xué)的開拓者，最早刊發(fā)了關(guān)于許氏祿豐龍的論文。

托馬斯說，他的研究涉及多門學(xué)科，大家可以稱他是進(jìn)化生物學(xué)家、古生物學(xué)家、鳥類學(xué)家、綜合生物學(xué)家，甚至是動(dòng)物考古學(xué)家。簡(jiǎn)單來說，他運(yùn)用各種方法研究來自中國(guó)和世界各地的鳥類化石，研究重點(diǎn)是鳥類的進(jìn)化。短短兩個(gè)小時(shí)的采訪，他帶領(lǐng)我們走進(jìn)神奇的古生物世界。

問：古生物學(xué)如何引發(fā)了您的興趣，并讓您投身其中？

托馬斯·斯坦哈姆（美國(guó)），獲加州大學(xué)伯克利分校綜合生物學(xué)博士學(xué)位，并在該校完成博士后研究。他曾在美國(guó)得克薩斯A&M大學(xué)工作。2012年來到中國(guó)，現(xiàn)任中國(guó)科學(xué)院古脊椎動(dòng)物與古人類研究所教授、中國(guó)科學(xué)院大學(xué)兼職教授。在《自然》《自然通訊》和《美國(guó)國(guó)家科學(xué)院院刊》等期刊上發(fā)表約80篇論文。Thomas Stidham (United States). He obtained his Ph.D. in integrative biology from the University of California at Berkeley. After graduation,he held a postdoctoral position in the University of California at Berkeley.He worked at Texas A&M University in the USA. He came to China in 2012, and he is a professor of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, and an adjunct professor of the University of Chinese Academy of Sciences. He has published about 80 papers with many in the leading journals of Nature, Nature Communications, and Proceedings of the National Academy of Sciences.

我從三歲起就對(duì)化石感興趣，那時(shí)父親給了我人生中的第一本恐龍書，我很快記住了所有恐龍的名字。有趣的是，多年后，我在第一次參加古生物學(xué)的專業(yè)會(huì)議上遇到了這本書的作者，一位已退休多年的科學(xué)家。四歲的時(shí)候，我開始在學(xué)校操場(chǎng)的礫石中收集貝殼，撿化石、捕捉昆蟲和蜥蜴、觀察巖石這樣的事情充滿了我的童年。我一直熱愛科學(xué)，在大學(xué)一年級(jí)上完第一堂地質(zhì)學(xué)課后，我便從工程專業(yè)轉(zhuǎn)到了地質(zhì)專業(yè)。從那時(shí)起，因?yàn)閷?duì)科學(xué)的熱愛、對(duì)古生物學(xué)的追求，我走遍了世界很多地方，包括北京，也讓我有了重大發(fā)現(xiàn)，增進(jìn)了我對(duì)脊椎動(dòng)物特別是鳥類進(jìn)化的了解。古生物學(xué)告訴我們?cè)S多不同的事情?；C明了進(jìn)化和滅絕的事實(shí)，幫助展示我們的歷史，讓我們知道我們從哪里來，并為我們提供了前進(jìn)方向的線索。對(duì)于古生物學(xué)家來說，每一天都在穿越時(shí)間，像個(gè)探險(xiǎn)家一樣，發(fā)現(xiàn)一個(gè)新物種或者揭開一頁(yè)無人知曉的歷史。

問：您是如何來到中國(guó)工作的？

這是我在中國(guó)的第11年了。12年前，我的中國(guó)朋友周忠和（原古脊椎動(dòng)物和古人類學(xué)研究所所長(zhǎng)）建議我來中國(guó)。我們?cè)谧x研究生的時(shí)候就認(rèn)識(shí)了，到現(xiàn)在已經(jīng)認(rèn)識(shí)25年了。當(dāng)時(shí)我正想調(diào)整一下工作，于是我申請(qǐng)來研究所做一年的訪問學(xué)者。原計(jì)劃只待一年，結(jié)果現(xiàn)在變成了11年，這其中一個(gè)重要原因就是我在這里的第一年遇到了我的中國(guó)妻子，這改變了我的生活方向；而且我很快就愛上了在北京的研究工作，也很開心和中國(guó)同事一起工作。我和中國(guó)很有淵源，兒時(shí)就夢(mèng)想來北京參觀、認(rèn)識(shí)很多中國(guó)古生物學(xué)家，還有我的博士后導(dǎo)師、著名古人類學(xué)家克拉克·豪威爾是尼克松總統(tǒng)訪華后第一批來到中國(guó)訪問的美國(guó)古生物學(xué)家之一，他被邀請(qǐng)來中國(guó)研究周口店北京人遺址化石，這次來訪是中國(guó)在化石研究領(lǐng)域開展國(guó)際合作的重要轉(zhuǎn)折點(diǎn)。

10多年前我剛到北京的時(shí)候，研究所做鳥類研究的同事大都在研究遼寧、河北、內(nèi)蒙古等地發(fā)現(xiàn)的熱河生物群的早期鳥類化石；相反，我的研究主要關(guān)注目前仍存在的一些鳥類的化石，像已滅絕的鴨子、野雞和貓頭鷹。當(dāng)時(shí)中國(guó)幾乎沒有人研究這個(gè)方向，我開始建立研究團(tuán)隊(duì)。因?yàn)椋袊?guó)有太多的鳥類化石可以研究了。

問：在您發(fā)表的論文中有很多鳥類化石的圖片，請(qǐng)您介紹一些在中國(guó)進(jìn)行野外實(shí)地考察、發(fā)現(xiàn)化石的經(jīng)歷。

我走過中國(guó)的很多地方，做科研或是旅游。例如，我在內(nèi)蒙古挖掘過恐龍骨骼，在山西農(nóng)村和新疆偏遠(yuǎn)地區(qū)發(fā)現(xiàn)過一些牙齒骨頭化石。當(dāng)然我在世界許多地方都做過實(shí)地考察，其實(shí)中國(guó)大部分的區(qū)域都或多或少被考察過了，除了青藏高原、新疆的一些非常偏遠(yuǎn)的地區(qū)。

我熱愛在世界各地做實(shí)地考察。野外工作大多是白天在夏日陽(yáng)光暴曬下12小時(shí)不停歇地仔細(xì)觀察地面（希望找到牙齒或骨頭化石碎片的一絲線索），晚上住在狹窄的帳篷里。但是，發(fā)現(xiàn)新化石、發(fā)現(xiàn)新化石遺址、與好朋友在一起、在滿是星星的天空看到美妙的日出和日落，以及看到野生動(dòng)物等，會(huì)讓我忘記這些所有的困難。

最令人興奮的是發(fā)現(xiàn)全新的東西。幾年前，我和研究所所長(zhǎng)鄧濤以及幾名研究生一起去了山西省榆社縣。榆社縣以哺乳動(dòng)物化石聞名。我們選擇了一個(gè)之前考察不多的區(qū)域，巖石層更新一些。我們采集了很多石頭，裝進(jìn)大袋子里，背到附近的河邊，然后用非常細(xì)的篩網(wǎng)沖洗掉數(shù)百公斤的沉淀物，以篩選出微小的骨骼和牙齒的化石。在把一塊石頭放進(jìn)篩網(wǎng)中時(shí)，我突然看到一塊破碎的鳥腳骨頭從石頭里伸出來。簡(jiǎn)單清理后，我立刻認(rèn)出它不僅是鳥，而且是鸊鷉——一種會(huì)潛水的鳥。中國(guó)還沒有發(fā)表過鸊鷉化石相關(guān)的論文，我當(dāng)時(shí)就知道自己發(fā)現(xiàn)了一種新的已滅絕的鳥類。這真是太棒了！

問：在中國(guó)工作了10余年，您感受如何？

中國(guó)在許多方面改變了我的生活。中科院古脊椎動(dòng)物和古人類學(xué)研究所是世界上頂級(jí)的古脊椎動(dòng)物研究所，作為一名科學(xué)家，在這里我能夠不斷成長(zhǎng)、推進(jìn)我的研究，我能夠與我的中國(guó)同事以及世界各地的合作者密切合作。我已與20多名同事合作發(fā)表了論文、獲得了科研基金。此外，我一直在研究這個(gè)世界上一些最神奇的化石。中國(guó)擁有大量化石，特別是恐龍、早期鳥類和人類化石。例如，我們剛剛發(fā)表了論文，介紹第一個(gè)在白天而不是晚上活動(dòng)的貓頭鷹化石，這改變了我們對(duì)貓頭鷹進(jìn)化的看法。總的來說，我在這里能一直專注于研究，這在其他地方可能無法做到。

此外，我在中科院大學(xué)教授《脊椎動(dòng)物骨骼比較學(xué)》課程，我們研究所的所有學(xué)生都必須學(xué)習(xí)這門課程，也有一些來自北京大學(xué)和清華大學(xué)的學(xué)生也來學(xué)習(xí)這門課程，因?yàn)槿本┲挥形覀冮_設(shè)這門課程。雖然我是鳥類專家，但我也非常了解各種脊椎動(dòng)物的骨骼，比如哺乳動(dòng)物、魚類甚至爬行動(dòng)物。我的同事會(huì)給我一堆動(dòng)物骨骼，讓我?guī)兔Ψ诸惒⒋_認(rèn)。我很喜歡這種工作，因?yàn)榭梢砸贿吢犚魳?，一邊通過顯微鏡觀察微小的骨骼來搜索新發(fā)現(xiàn)，而不是在電腦前伏案。除了常規(guī)教學(xué)工作，我還花了大量時(shí)間培養(yǎng)學(xué)生如何成為科學(xué)家，尤其是指導(dǎo)他們把自己的發(fā)現(xiàn)寫成英文論文。講好科學(xué)故事，這也是一種技能，我努力把它教授給學(xué)生們。

問：為什么中國(guó)對(duì)古生物學(xué)研究很重要？

中國(guó)對(duì)古生物學(xué)研究很重要有很多原因。其中一個(gè)重要原因是中國(guó)的科學(xué)家，中國(guó)有一些優(yōu)秀的古生物學(xué)家和科學(xué)家。他們使用尖端技術(shù)和最好的方法來研究生命的進(jìn)化。我們的研究所擁有先進(jìn)的實(shí)驗(yàn)室和設(shè)施，如古代DNA實(shí)驗(yàn)室、解剖實(shí)驗(yàn)室、高效的電腦網(wǎng)絡(luò)、CT掃描儀和其他設(shè)備。

同時(shí)，中國(guó)是世界上研究恐龍的領(lǐng)先地區(qū)之一。如果你看看中國(guó)的地質(zhì)歷史，中國(guó)大部分地區(qū)在過去數(shù)百萬年中都是陸地，而美國(guó)則部分被海洋覆蓋。所以在中國(guó)會(huì)有很多陸地化石，很多恐龍，但鯊魚和鯨魚的化石很少。在中國(guó)發(fā)現(xiàn)了很多的化石，提供了大量的證據(jù)，證明了恐龍并不是都滅絕了，比如獸腳類恐龍就進(jìn)化成了我們今天的鳥類。第一個(gè)帶羽恐龍的化石就來自中國(guó)，我們?cè)谥袊?guó)東北發(fā)現(xiàn)了很多帶羽恐龍的化石。在中國(guó)，很多學(xué)者從事從恐龍到鳥類進(jìn)化的研究。2021年我們?cè)凇蹲匀煌ㄓ崱飞习l(fā)表了一篇論文，證明了早期鳥類頭骨的許多特征與霸王龍等恐龍相同，但與當(dāng)今鳥類頭骨的結(jié)構(gòu)和功能是不同的。事實(shí)上，很多早期鳥類仍然具有許多恐龍的特征。

青藏高原也是另一個(gè)重要的研究區(qū)域。鄧濤所長(zhǎng)及其團(tuán)隊(duì)的工作表明，在200萬年前的冰河時(shí)期，許多最初在寒冷、干燥的青藏高原生活的動(dòng)物擴(kuò)散到了歐洲、亞洲甚至北美。200多萬年前，正是全球氣候變得更冷、更干旱的時(shí)期，這些變化讓這些動(dòng)物擴(kuò)大他們的居住范圍，它們甚至到了北京。青藏高原的隆起如何影響氣候變化和亞洲動(dòng)物的進(jìn)化，我們對(duì)此非常感興趣。因此，我的研究主要關(guān)注青藏高原的鳥類化石，希望能把這個(gè)進(jìn)化的歷程描述得更清晰。

問：中國(guó)古生物學(xué)研究近年來有怎樣的進(jìn)展？

在過去的二三十年中，中國(guó)在古生物學(xué)研究方面發(fā)生了巨大的變化。毫無疑問，中國(guó)在化石、生命演化研究的許多方面已經(jīng)成為研究重鎮(zhèn)，這一點(diǎn)得到了大家的認(rèn)同。這得益于全國(guó)發(fā)現(xiàn)了許多化石遺址，培養(yǎng)了新一代訓(xùn)練有素的科學(xué)家，以及在重要研究問題上開展了國(guó)際合作。正是這些進(jìn)展讓我在中國(guó)的生活和事業(yè)蒸蒸日上。中國(guó)在脊椎動(dòng)物進(jìn)化的許多領(lǐng)域處于領(lǐng)先地位，不斷有突破性的發(fā)現(xiàn)和論文發(fā)表，而且中國(guó)古生物學(xué)家已經(jīng)很好地融入了全球?qū)W術(shù)界。

問：您發(fā)表了很多關(guān)于鳥類化石的科研論文。您是如何根據(jù)化石做研究的？

托馬斯在野外進(jìn)行實(shí)地考察

一切都是從化石開始的。對(duì)于鳥類骨骼化石，首先你需要確定它是哪一塊骨頭。然后要仔細(xì)觀察骨骼上的特征，比如肌肉附著處的痕跡、與其他骨骼連接的關(guān)節(jié)以及任何洞或開口。對(duì)于比較完整的頭骨或骨骼，我們會(huì)進(jìn)行CT掃描，這樣可以獲得表面和內(nèi)部的詳細(xì)信息。我在世界各地的博物館看過成千上萬的各類鳥類的骨骼，我可以根據(jù)骨頭的特征來識(shí)別某一特定鳥類的身份。由于我研究當(dāng)今的鳥類群體，我必須將化石與當(dāng)今世界存在的1萬多種鳥類的骨骼以及200多年來已發(fā)表的鳥類化石進(jìn)行比較。在知道了一塊化石是哪種鳥類之后，我用許多不同學(xué)科的知識(shí)來回答關(guān)于古代鳥類如何進(jìn)化、生活和死亡這些問題。例如，我們利用鳥類骨骼中的膠原蛋白、使用穩(wěn)定同位素技術(shù)來分析它們當(dāng)時(shí)吃什么食物。我們可以做到這一點(diǎn)是因?yàn)楣趋乐械乃袞|西都來自我們吃的食物和水。你的骨頭和牙齒中隱藏著你吃了什么的記錄，當(dāng)然要通過詳細(xì)的化學(xué)分析才能知道。類似的，關(guān)于貓頭鷹白天行為的發(fā)現(xiàn)，涉及許多不同的研究領(lǐng)域，包括收集詳細(xì)的數(shù)據(jù)、利用幾何學(xué)重建貓頭鷹眼睛的大小和形狀、與數(shù)百種鳥類和爬行動(dòng)物進(jìn)行比較、對(duì)比它在鳥類族譜中的位置，以及研究當(dāng)今鳥類的行為習(xí)慣等?，F(xiàn)代古生物學(xué)已跨越了傳統(tǒng)學(xué)科的界限，我們可以使用任何可能的方法來提高我們對(duì)生命演化的認(rèn)識(shí)。

問：您認(rèn)為古生物學(xué)研究的意義何在？

首先是了解我們這個(gè)星球的歷史。每一塊新化石都可以講述一個(gè)新故事，或者是為已知的世界增加新的更豐富的信息，或者是改變我們之前的認(rèn)識(shí)。簡(jiǎn)單如一塊骨頭或者一顆牙齒就可以改變我們對(duì)地球歷史和演化的看法?；菍?duì)遠(yuǎn)古歷史的唯一直接記錄?；凸派飳W(xué)激發(fā)了人們的想象力。對(duì)許多孩子來說，是恐龍和化石為他們打開了科學(xué)的大門。

在我發(fā)表關(guān)于第一塊來自青藏高原的鳥骨化石的論文之前，科學(xué)家們只能推測(cè)高原鳥類的歷史故事。作為一名鳥類專家，我曾多次前往青藏高原觀察鳥，雖然我們知道今天生活在那里的生物，但沒有化石我們無法知道它們的歷史。這塊鳥骨化石來自一種目前在西藏非常普遍的鴨子——麻鴨，這一塊化石就證明它們已經(jīng)在這里生活了數(shù)百萬年。

我專門研究當(dāng)今鳥類的化石和進(jìn)化，研究重點(diǎn)是建立鳥類進(jìn)化譜系，研究鳥類如何應(yīng)對(duì)過去的氣候變化?；仡櫟厍虻臍v史，它曾有過比今天更暖或更冷的時(shí)期。隨著當(dāng)前全球變暖，我很想了解氣候和環(huán)境變化如何影響世界各地的鳥類。通過化石記錄，我們不僅可以看到過去100年來的氣候變化對(duì)動(dòng)物的影響（很多記錄顯示鳥類分布、飲食和體重發(fā)生了變化），還可以觀察過去更早的時(shí)期，以此了解全球變暖未來可能給當(dāng)今的動(dòng)物帶來什么影響。通過對(duì)來自北極的一些鳥類化石的研究，我證明了在5000萬年前氣候變暖的情況下，許多鳥類向北移動(dòng)了數(shù)千公里進(jìn)入北極圈，然后從一個(gè)大陸又到另一個(gè)大陸。氣候變化將給我們和鳥類帶來怎樣的未來呢？

問：近年來極端天氣頻發(fā)，古生物學(xué)的研究對(duì)我們?nèi)绾螒?yīng)對(duì)氣候變化有怎樣的借鑒意義？

我們剛剛談了過去100年間的氣候變化。接下來的問題是，未來一百年或一千年會(huì)發(fā)生什么。化石和巖石記錄是回答這個(gè)問題的關(guān)鍵。我們可以看到許多物種滅絕發(fā)生在上一次冰河時(shí)代結(jié)束后的變暖時(shí)期。在一項(xiàng)研究中，我們?cè)噲D弄清楚為什么一些大型食肉鳥類滅絕了，另一些卻沒有。結(jié)果是，一種名為teratorns的鳥（陸地上最大的飛鳥），因?yàn)樗鼈兊氖澄锩歪锵蠛腿辇X象滅絕而滅絕了；加利福尼亞禿鷹僅在加利福尼亞州幸存下來，因?yàn)樵谶@里他們還能吃到鯨和海豹等海洋動(dòng)物。類似的研究和數(shù)據(jù)可以幫助我們?cè)谖磥淼臍夂蜃兓斜Ｗo(hù)鳥類多樣性，可以根據(jù)歷史預(yù)測(cè)將來會(huì)發(fā)生什么。我們通過預(yù)測(cè)一些動(dòng)物會(huì)向哪里遷移來幫助我們做好規(guī)劃，比如新建或擴(kuò)建國(guó)家公園，或者是制訂其他全新的計(jì)劃。正因如此，我把重點(diǎn)放在對(duì)當(dāng)今鳥類的研究，而不是那些早已滅絕的、有著恐龍般牙齒的早期鳥類。

問：今年7月全國(guó)科技活動(dòng)周期間，您參與“外國(guó)專家科學(xué)講堂”項(xiàng)目為青少年做科普講座，在中國(guó)做科普感受如何？

除了教授課程外，我還投入了大量精力做科普，包括在古動(dòng)物館組織恐龍之旅、公開講座、恐龍之夜活動(dòng)。古動(dòng)物館館長(zhǎng)王原非常支持我從事恐龍相關(guān)的科普活動(dòng)。此外，我經(jīng)常在周口店北京人遺址及其博物館組織家庭科普活動(dòng)，也在北京周邊組織昆蟲和鳥類的觀察活動(dòng)。我還走進(jìn)許多學(xué)校，就恐龍、化石、鳥類和其他科學(xué)主題演講，很高興看到孩子們與化石和動(dòng)物親密接觸。家長(zhǎng)們總是會(huì)給我發(fā)孩子們的照片或視頻，展現(xiàn)他們對(duì)昆蟲、巖石和大自然日漸濃厚的興趣，看到科普和教育活動(dòng)給孩子們帶來的這些變化，我很自豪，希望他們能夠繼續(xù)參與，甚至有一天來和我一起工作。我正在利用北京最好的資源來激發(fā)下一代中國(guó)科學(xué)家對(duì)科學(xué)的興趣。

雖然一本書或一部《侏羅紀(jì)公園》會(huì)引起孩子們的興趣，但我相信像我這樣的科學(xué)家更應(yīng)該發(fā)揮重要作用，向大眾傳播科學(xué)知識(shí)，激發(fā)他們的科學(xué)熱情和想象力，并向他們展示如何實(shí)現(xiàn)科學(xué)夢(mèng)想。

問：工作之余您喜歡做些什么？

首先，我喜歡探索中國(guó)這個(gè)國(guó)家。從爬長(zhǎng)城到參加貴州的少數(shù)民族節(jié)日，我去過中國(guó)大部分地區(qū)。青藏高原仍然是我最喜歡的地方之一，我一直計(jì)劃著再次去那里觀察鳥類和品味文化。在北京，我經(jīng)常上烹飪課，學(xué)習(xí)如何制作傳統(tǒng)的中國(guó)美食，比如月餅、豆腐和餃子。此外，因?yàn)槲已芯盔B類，所以只要有機(jī)會(huì)我就會(huì)去觀鳥。中國(guó)有很多種類的鳥類，在過去的幾年里，我一直嘗試拍攝更多的照片。我對(duì)中國(guó)的探索還遠(yuǎn)遠(yuǎn)沒有結(jié)束，還有很多東西等待我去發(fā)現(xiàn)。在中國(guó)生活了這么多年后，當(dāng)人們問我來自哪里時(shí)，我通?；卮鸨本３赡旰?，這里是我生活最久的地方。在我心里，我覺得自己就是個(gè)北京人。（托馬斯愛人王穎為采訪和本文撰寫提供幫助，特此致謝）

On the evening of July 29, 2022, Thomas A. Stidham, a professor of the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP),Chinese Academy of Science, gave a lively science lecture to the assembled children and families titled “Birds are Amazing Flying Dinosaurs”at the Paleozoology Museum of China. He surveyed the different lines of evidence demonstrating that birds are the living descendants of dinosaurs. He focused on how they stand and walk, their shared bone structures and shapes, the characteristics of their feathers and eggs,and other body parts.

Thomas, from the United States, has worked in China for more than ten years and is a leading expert in the fossil record and evolution of birds worldwide. Our interview with Thomas was in the science classroom for educational activities at the Paleozoology Museum of China.The museum may not be large, and it tells stories of the fossil record of vertebrates from across China. It records the spectacular discoveries of feathered dinosaurs, early jawed fish, the first humans living in China and Beijing, and even, the first dinosaur independently discovered, excavated, and studied by Chinese paleontologists. In addition, the classroom walls are covered with photos of Yang Zhongjian,also known as C.C. Young. Yang is perhaps the most famous Chinese geologist and paleontologist. He pioneered Chinese paleontology and helped to found China’s studies in ancient vertebrate evolution, including describing the first Chinese dinosaur,.

Thomas explains that he pursues many scientific pathways in his research, and he may be called an evolutionary biologist, a paleontologist,an ornithologist, an integrative biologist, or even a zooarcheologist.Despite that seemingly broad approach to science, he focuses his studies on the evolution of birds by examining their fossils from China and around the world. Over our two-hour-long interview, he helped us to dive into the magical world of ancient creatures.

：

Thomas A. Stidham: I’ve been interested in fossils since I was three.My father gave me my first dinosaur book at that age, and I quicklyremembered the names of all of the dinosaurs in that book and others.The funny thing is that I met the long-retired scientist author of that book many years later while attending my first professional paleontology meeting. When I was four, I started collecting fossil shells in the gravel of my school playgrounds, and I picked up fossils, caught insects and lizards, and looked at rocks throughout my childhood. Science was crucial to my life, and my scientific passion has never stopped. After taking my first geology class during my first year of college, I changed my major to geology from engineering. My pursuit of paleontology, and science in general, has since taken me around the world, including Beijing. It has allowed me to make critical discoveries impacting what we know about the evolution of vertebrates, particularly birds. The study of paleontology and the fossil record tells us many different things. Beyond fossils demonstrating the facts of evolution and extinction, they help to show us ourhistory on this planet, tell us where we came from, and give us clues as to where we might be going. For a paleontologist, every day is traveling through time and being an explorer who can discover a new species or uncover a page of history that no one knew even existed.

：

Thomas A. Stidham: This is my 11th year in China. About 12 years ago,a Chinese friend and colleague, Zhou Zhonghe (former IVPP director),suggested I come to China. I have known him for over 25 years since we were graduate students. At that time, I was looking for a change in my career. So, I applied as he suggested and was awarded a one-year visiting position in the IVPP. That year has since become 11, partly because I met my Chinese wife during my first year, radically changing my direction in life, but also because I quickly grew to enjoy my Beijing-based research and work with my Chinese colleagues. I have always had links and dreams related to China. I know many Chinese paleontologists and have wanted to visit Beijing since childhood. My postdoctoral advisor,Clark Howell, was an eminent paleoanthropologist. Clark was part of the first group of American paleontologists invited to Beijing to study fossils from the Zhoukoudian Peking Man site after President Nixon visited China. Their visit nearly 50 years ago in 1975 marks a turning point in international cooperation on studying fossils from China.

When I arrived in the IVPP a decade ago, most of the people that study birds here worked on the fantastic fossil skeletons of the early members of bird evolution from the spectacular Jehol Biota found in fossil deposits in Liaoning, Hebei, and Inner Mongolia. However, my focus is mainly on the fossils of living groups of birds, like extinct ducks, pheasants,and owls. At that time, no one was doing what I was doing anywhere in China, and I started to build that research strength in Beijing because there are so many fossil birds in China to study.

：

Thomas A. Stidham: In China, I have traveled across much of the country for pleasure and research. From digging up dinosaur bones in Inner Mongolia to finding tiny teeth and broken bones in rural Shanxi and remote parts of Xinjiang, I have helped recover thousands of fossils, including new species in our institute. While I’ve found new fossil specimens in China, I have continued to work on bird fossils from around the world. I love doing fieldwork all over the world. However,fieldwork can be seemingly endless days of carefully looking at the ground under a bright summer sun for 12 hours nonstop (hoping for the hint of a fossil tooth or bone fragment). Then there are the rough nights in the same cramped tent. Nevertheless, there is unparalleled excitement in finding new fossils and fossil sites. Not to mention, being with good friends, seeing fantastic sunrises and sunsets with skies full of stars, and watching unique wildlife in remote areas can make one forget all of those hardships.

Finding something that no one has ever seen is exciting. I went with Deng Tao, director of IVPP, and several graduate students to Yushe County in Shanxi Province several years ago. Yushe County is well known for its mammal fossils. We explored an area that had not been visited before, where the rocks are a bit geologically younger. We collected heavy bags of rocks with fossils and carried them on our backs to the nearby river. We washed the hundreds of kilograms of sediments through fine screens to capture the tiny fossil bones and teeth as the deposits were washed away. I was pulling the rocks out of the bags to put into the screens and saved one stone from destruction in the screens because I saw a small broken bird foot bone sticking out from the rock.After cleaning it a little with my finger, I recognized it instantly as a bird bone and a bone from a diving bird called a grebe. There are no published papers on fossil grebes (yet) from China, and I knew then that I had just found a new extinct bird species. It was amazing!

：

Thomas A. Stidham: China changed my life in many ways. IVPP is the top institute for vertebrate paleontology in the world. As a scientist, I have grown and developed my research. I’ve been able to work closely with my Chinese colleagues, as well as with student and professional collaborators around the world. The institute is filled with great colleagues, students, and friends, and I’ve published papers or obtained research grants with more than 20 of my colleagues. In addition, I have worked on some of the most fantastic fossils in the world. China has many spectacular fossils, particularly dinosaurs, early birds, and humans. For example, we just published a paper on the first fossil owl active during the day, not at night, and that single fossil skeleton has changed our view of owl evolution. Overall, I’ve been able to focus on and develop my research in ways I wouldn’t have been able to elsewhere.

I have taught our comparative vertebrate osteology course at the University of Chinese Academy of Sciences for a decade with a few other faculty members. All students in our institute have to take that class.We even get some students from Peking University and Tsinghua University because we offer the only vertebrate osteology class in Beijing.Though I’m an expert on birds, I know very well the skeletons of most groups of vertebrates, like mammals, fish, and even reptiles. Word of my knowledge has spread, and many of my colleagues will give me their unidentified and random fossil bones, asking me to sort through and identify them. I enjoy that kind of work, not on the computer where I can listen to music, stare through the microscope at tiny bones,and make endless discoveries. In addition to formally teaching students in the classroom, I spend a lot of time working with our students to train them to be professional scientists, in particular by helping them to write and publish their papers on their brilliant discoveries in English. Telling fantastic science stories is a skill I try to pass on to our students.

：

Thomas A. Stidham: There are many reasons why China is crucial.One of those reasons is the people. We have some excellent paleontologists and scientists here. They use cutting-edge equipment and the best analyses, techniques, and methods to study the evolution of life. Our institute also has some of the best facilities in the world, with multiple CT scanners, an ancient DNA lab, an anatomy lab, a great computer network, and other scientific equipment.

China is one of the top places in the world to study dinosaurs and other kinds of animals. If you look at the geological history of China, much of China’s land has existed over many millions of years of geological history. By contrast, America was covered partially by various oceans and seaways during large parts of geological time. As a result, in China, you get more fossils of animals that live on land, like dinosaurs, but very few fossils of sharks or whales. China also provides some of the best fossil materials and key proof to show that not all dinosaurs are extinct;birds evolved from one group of dinosaurs, called theropod dinosaurs.The first fossils of feathered dinosaurs were found in China, and we have discovered many new large and small species of feather dinosaurs in northeastern China. Many people study the evolutionary transition from dinosaurs to birds in China. For example, we published a paper inlast year describing our discovery that many features of early bird skulls are shared with dinosaurs likeand differ from the structure and function of living bird skulls.However, many of these early birds retained many features of their dinosaur ancestors.

The Tibetan Plateau is another significant area for research. Deng Tao and his group’s work has shown that during the ice ages over the last 2 million years, many groups of animals that first evolved on the cold and dry Tibetan Plateau spread out of Tibet into the cold and arid habitats of ice age across Europe and Asia, with some even immigrating to North America. The change to a more challenging and drier global climate more than 2 million years ago allowed these animals to expand their ranges over large areas, including Beijing. We are very interested in understanding the role of the rise of the Tibetan Plateau on climate change and the evolution of animals across Asia. I am trying to fill in the part of that story with my studies concerning the fossil record of birds from the plateau.

：

Thomas A. Stidham: In the last 20 to 30 years, many significant changes have taken place in China related to the study of paleontology. Indeed,the recognition of China as a center of excellence for studying many aspects of the fossil record and the evolution of life has increased significantly. That increase results from many amazing fossil site discoveries across the country, the development of a new generation of well-trained scientists, and international cooperation on essential questions in evolu-tion. Those qualities have led me to a life and career in China. As a result,China is leading the study of many areas of vertebrate evolution with ongoing groundbreaking discoveries and publications, and its paleontologists are well-integrated into global research circles.

：

Thomas A. Stidham: Everything starts with the fossil specimen. For a bird bone fossil, first, you need to determine which bone of the skeleton it is. Then, you have to look in detail at the features on the bone,like scars from where muscles are attached, articulations with other bones, and any natural holes or openings. For more complete skulls or skeletons, we will CT-scan the fossils to get detailed information on the surface of the bones and what we usually cannot see inside bones and skulls. As an expert who has looked at thousands of bird skeletons of all groups of birds in museums around the world, I know how to use the features of the bones to exclude some groups as potential identifications. I also know how to obtain the evidence I need to support the best identification of a particular group or species of birds. Since I work on living groups of birds and birds flying everywhere in the world,workers like me have to compare fossils to skeletons of the over 10,000 species of living birds around the world and over 200 years of published fossil birds. After we know what kind of bird the fossil belongs to, I use many different fields of science to answer questions about how ancient birds evolved, lived, and died. For example, we used fossilized stable isotopes of several atomic elements found in the collagen proteins preserved in some bird bones to help reconstruct what long-dead birds ate. We can do that because everything in your bones starts as food and water through your mouth. Your bones and teeth keep a hidden record of what you eat that can only be read with detailed chemical analysis.Similarly, our project examining the oldest record of daytime behavior in owls involved several different lines of study, from gathering precise measurements and using geometry to reconstruct the size and shape of the eye in a fossil owl and comparing it to hundreds of species of birds and reptiles to examining the day and night behaviors across living birds in comparison to their placement in the bird family tree. Old traditional boundaries do not restrict modern paleontology among the sciences, but we use appropriate methods to improve our knowledge of past life.

：

Thomas A. Stidham: Firstly, I think paleontology allows us to know our history on this planet. Every discovery, or new fossil, can either add something to that story or it can change everything about what we thought we knew. It can take as little as one bone or tooth to completely change our view of Earth’s history and evolution. Fossils and the rocks they are found in are the only direct record of what happened in the deep past. Fossils and paleontology light the imagination of people around the world. For many children, dinosaurs and fossils are their introductions to science.

Before I published the first fossil bone of a bird from the Tibetan Plateau, scientists could only speculate about the story of birds on the plateau. As a bird specialist, I have gone to the Tibetan Plateau many times to watch living birds, and while we can see what lives there today, we have no idea what their history is without fossils. So it happens that the fossil from the Tibetan Plateau that I reported is from a group of ducks called a shelduck, and that type of duck is quite common across the Tibetan region today. So this single bone fossil helps to show that they have lived there for millions of years and are not recent arrivals.

As I’ve said, I specialize in the evolution and fossil record of the living group of birds. My research focuses on building the family tree of birds as a document of their evolution and studying how birds have responded to past climate change. If we look at the history of the Earth,we can see periods when it was warmer or colder than today. With current global warming, I am interested in understanding how climate and environmental change impact birds worldwide and over time. Instead of just seeing the impact of climate change on animals over the last 100 years (with many documented changes to bird distributions, diets,and body masses), the fossil record allows us to look over much more extended periods and potentially see what the future global warming may bring to the animals alive today. For example, in my study of some fossil birds from the Arctic, I showed that with a warming climate 50 million years ago, different groups of birds moved thousands of kilometers further north into the Arctic Circle, which then spread from one continent to another. So what future does climate change have in store for birds and us?

：

Thomas A. Stidham: We just talked about the last 100 years of climate change. The natural question is what will happen in the next hundred or thousand years. The fossil and rock records are crucial to answering that question. We can see many extinctions during the last significant warming event after the end of the last ice age. In one of my studies, we tried to figure out why some large carnivorous birds became extinct,and others didn’t. Our analyses showed that one extinct group of birds called teratorns (giant flying birds on land) ate dead mammoths and mastodons (which became extinct, too). The endangered California Condor ate many of the same animals across North America. Teratorns became extinct because their food became extinct. However, the California Condor survived the extinction event only in California, where it was able to eat meat from marine animals like dead whales and seals.Data like those and from other studies on birds can help us plan to conserve bird diversity in the future of climate change by using what happened in the past to predict what will happen soon. We can predict where species should move, and that knowledge can help us to plan for conservation work to protect biological diversity, like building new national parks, expanding existing ones, or developing plans we haven’teven thought of yet. This kind of research and broader impact is why I focus on the living groups of birds, not the long-extinct, early-toothed dinosaur-like birds.

：

Thomas A. Stidham: Beyond my teaching and effort to train future scientists in China, I’ve put in a lot of effort to promote engagement with science and science careers in Beijing. This work includes developing, organizing, and leading many “dinosaur expert” tours for students and families, public talks, and a family overnight dinosaur program in the museum. The museum director, Wang Yuan, has supported my dinosaur outreach activities. In addition, I frequently run a popular family activity and tour at the UNESCO Zhoukoudian “Peking Man” Site and Museum and other insect and bird field experiences around Beijing. I also have visited many school classrooms across Beijing, giving talks and running activities about dinosaurs, fossils, birds,insects, and other science topics. Seeing the excited children engaging with the fossils and animals I love is great. I also am proud to see the long-term impact of my educational programs as parents continue to send me photos or videos of their children months later showing their ongoing discoveries and interests in insects, rocks, and nature, as well as their wish to join my next program or even coming to work with me someday. I am using the best resources in Beijing to light the imagination and interest in science among the next generation of scientists.While a book or a Jurassic Park movie might garner a child’s interest for a moment, I believe that active research scientists like myself need to play a significant role in communicating not only our knowledge of science but also our passion for science to capture the imagination of the public and show them how to make their science daydreams a reality.

：

Thomas A. Stidham: First, I enjoy exploring the country. From hiking the Great Wall to visiting minority festivals in far-flung places like rural Guizhou, I have seen most parts of China during my time here.The Tibetan Plateau is one of my favorite places in the world, and I’m always planning to return for its rich bird life and culture. In Beijing, I also frequently take cooking classes, learning to make traditional Chinese dishes from scratch, like mooncakes, noodles, tofu, and dumplings. Additionally, since I study birds, I try to watch birds whenever I can. China and Beijing have many species of birds, and I have been trying to take more pictures of them in the last few years. I am far from done exploring China, and I think there is so much left to discover. After being a part of China for so long, I will typically answer Beijing when people ask me where I am from. I have lived here longer than any other place in my adult life, and in my heart, I feel I am a Beijinger now.