即使最讓人恐怖的食肉恐龍也曾有自己的童年。
如今,，科學(xué)家在蒙古發(fā)現(xiàn)了霸王龍（Tyrannosaurs rex）的一個(gè)最不成熟的親戚——一只近乎完好的2到3歲（相當(dāng)于人類的7到8歲）的恐龍化石。
根據(jù)5月9日發(fā)表在《古脊椎動(dòng)物學(xué)期刊》上的一篇論文,，這具生活在7000萬年前的白堊紀(jì)的恐龍化石屬于特暴龍（Tarbosaurus bataar）,，這是暴龍家族中的一種龐大的食肉恐龍，其從頭至尾的長度相當(dāng)于一幢4層高的樓房,。
經(jīng)過詳盡的解剖分析,，日本東京市自然與科學(xué)國家博物館的TAKANOBU TSUIHIJI與蒙古和美國的同事認(rèn)為，這只幼小的恐龍——其體型與成人相仿——尚不能像它的父母那樣碾碎骨骼,，或是運(yùn)用下顎強(qiáng)勁的咬合力與切向力,。
因此，與那些并未與其同行且以其他大型恐龍為食的成年個(gè)體不同,，幼小的特暴龍很可能會(huì)捕食小型的爬行動(dòng)物,。
研究人員指出，在動(dòng)物王國中,，一個(gè)幼年個(gè)體與一個(gè)成年個(gè)體之間在飲食上的差異如此之大確實(shí)非常罕見,，并且在恐龍的世界中也是史無前例的。
研究人員表示,，如果古生物學(xué)家對于特暴龍的了解尚不及現(xiàn)在的多,，那么他們很可能將這一幼年個(gè)體劃歸為另一個(gè)物種。
霸王龍又名暴龍，是一種大型的肉食性恐龍,，身長約13米,，體重約7噸，生存于白堊紀(jì)末期,。目前大量的化石材料使得科學(xué)家有足夠的資料研究暴龍生理的各個(gè)層面,，包括生長模式與生物力學(xué)，有些研究人員也發(fā)現(xiàn)了軟組織與蛋白質(zhì),。但霸王龍的食性,、生理機(jī)能以及移動(dòng)速度，仍在爭論當(dāng)中,。（生物谷Bioon.com）
生物谷推薦原文出處：
Journal of Vertebrate Paleontology DOI： 10.1080/02724634.2011.557116
Cranial osteology of a juvenile specimen of Tarbosaurus bataar (Theropoda, Tyrannosauridae) from the Nemegt Formation (Upper Cretaceous) of Bugin Tsav, Mongolia
Takanobu Tsuihiji;Mahito Watabe;Khishigjav Tsogtbaatar;Takehisa Tsubamoto;Rinchen Barsbold;Shigeru Suzuki;Andrew H. Lee;Ryan C. Ridgely;Yasuhiro Kawahara;Lawrence M. Witmer
A juvenile skull of the tyrannosaurid Tarbosaurus bataar found in the Bugin Tsav locality in the Mongolian Gobi Desert is described. With a total length of 290 mm, the present specimen represents one of the smallest skulls known for this species. Not surprisingly, it shows various characteristics common to juvenile tyrannosaurids, such as the rostral margin of the maxillary fenestra not reaching that of the external antorbital fenestra and the postorbital lacking the cornual process. The nasal bears a small lacrimal process, which disappears in adults. Lacking some of the morphological characteristics that are adapted for bearing great feeding forces in adult individuals, this juvenile specimen suggests that T. bataar would have changed its dietary niches during ontogeny. The numbers of alveoli in the maxilla (13) and dentary (14 and 15) are the same as those in adults, suggesting that they do not change ontogenetically in T. bataar and thus are not consistent with the hypothesis that the numbers of alveoli decreases ontogenetically in tyrannosaurids.
