在接下來幾年,奧斯特倫姆及格蘭特·邁耶(Grant E. Meyer)研究這些新發現化石,以及布朗所命名的"Daptosaurus"化石,發現牠們是同種生物,並在1969年將這些化石命名為平衡恐爪龍(Deinonychus antirrhopus)。種名antirrhopus意為「平衡」,指的是牠們堅挺尾巴的可能用途[20]。同年,奧斯特倫姆公布更廣泛的恐爪龍專題論文[19]。
在Cloverly組,常在腱龍化石的附近發現恐爪龍的牙齒。而在其中兩個採石場,已發現相當完整的恐爪龍化石,就位在腱龍化石的附近。第一個是蒙大拿州Cloverly組的耶魯採石場,發現過四個恐爪龍的成年個體與一個幼年個體,以及眾多的牙齒。基於在同一位點發現大量恐爪龍的骨骼,且在腱龍的附近發現恐爪龍的牙齒,估計恐爪龍是獵食腱龍的。奧斯特倫姆與德斯蒙德·麥斯威爾(W. Desmond Maxwell)更以此推斷恐爪龍是成群生活及獵食的[37]。第二個採石場則位在奧克拉荷馬州的鹿角組。該地發現六個腱龍的部份骨骸,體型不一,附近另有一個恐龍的部份骨骸與眾多牙齒。一個腱龍的肱骨上有齒痕,可能是恐爪龍所留下。在1998年,丹尼爾·布林曼(Daniel L. Brinkman)等人提出成年的恐爪龍為70到100公斤,而成年腱龍為1到4公噸。單一的恐爪龍無法獵殺成年的腱龍,顯示牠們應是採群體方式獵食腱龍[38]。
但是在2007年,布林曼與B. T. Roach基於現今肉食性動物的獵食方式及腱龍位點的埋葬學,質疑了恐爪龍在群獵時的合作性行為。現今的主龍類(鳥類及鱷魚)及科莫多龍有少數的合作性捕獵,不過牠們主要是單獨獵食,或是被吸引至已死的屍骸,而會為了搶食獵物屍體而發生打鬥。例如,當一群科莫多龍一同攝食時,最大的會先吃,且會攻擊其他嘗試吃食的較小型科莫多龍;如果小型的科莫多龍被殺死,牠們的屍體會被同類搶食。當這些資料套用在腱龍與恐爪龍的位點時,這似乎與科莫多龍與鱷魚的攝食模式很吻合。在這些位點發現的恐爪龍骨骼都是接近成年的,而失去了的部位可能是被其他恐爪龍吃了[39]。在2007年,科學家們在中國山東省發現了第一個大量的馳龍科足跡化石。這個足跡化石可能是由大型馳龍科恐龍所留下,而且是由六個相近大小的個體,沿者海岸共同前進。這些個體相距約一公尺,朝同一方向緩慢前進。研究人員提出,雖然該足跡化石並不能明確指出馳龍科的獵食行為,但無法排除牠們以群體獵食的可能性[40]。
在1970年,約翰·奧斯特倫姆曾參考鴕鳥與食火雞,發現這些鳥類會用較大型的第二趾爪攻擊獵物,進而產生恐爪龍會利用第二趾爪攻擊獵物的理論[19]。食火雞的第二趾爪可長達12.5公分[49]。奧斯特倫姆並引用一個1958年的鳥類論文,認為後肢與第二趾爪,可用來將獵物的身體撕開、將內臟挖出[50]。在近年,Chhristopher P. Kofron研究241件食火雞的攻擊紀錄,發現總計有1個人類、2隻狗的被攻擊死亡案例,但沒有證據顯示食火雞會用第二趾爪將獵物的內臟挖出[51][52]。相反地,食火雞將趾爪作為防衛武器,攻擊對牠們產生威脅的動物、或威嚇對方[49]叫鶴也具有較大的第二趾爪,卻是用在撕裂小型獵物,以適合吞嚥。[53]。在2011年的一項恐爪龍類趾爪研究,也認為第二趾爪無法作出有效的刺穿、劃開獵物身體的動作,並提出第二趾爪有固定獵物功能的理論[41]。
在2002年,肯尼思·卡彭特(Kenneth Carpenter)的生物力學研究,確認了恐爪龍的前肢最可能是用來捉住獵物的,因為其前肢的長度較其他獸腳亞目更易於捕捉。大及長的鳥喙骨顯示,恐爪龍有強壯的前肢肌肉,更加強了這個解釋[54]。卡彭特的研究也製作骨頭模型來實驗。實驗證明恐爪龍是不能掘曲牠的手臂,像鳥類般緊貼身體,這與嘉克斯·高斯特(Jacques Gauthier)[55]及葛瑞格利·保羅(Gregory S. Paul)兩人在80年代的各別推論有所不同[4]。
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