长脖子的蜥脚类恐龙可能并非像电影和艺术作品中描绘的那样是群居的巨兽。
据美国《科学》杂志在线新闻报道，与成群生活不同，一些蜥脚类恐龙——例如阿拉莫龙——可能是一种孤独的动物，它们只有在年幼的时候才会短暂地聚集在一起。
古生物学家在美国蒙大拿州和得克萨斯州发现了两个保存完好的恐龙“墓穴”，其中的恐龙全部为年轻个体。这些小恐龙可能是干旱的牺牲品，而研究人员在这两个墓穴中并没有发现任何成年蜥脚类恐龙的化石，这意味着小恐龙完全没有受到大恐龙的照顾。古生物学家推测，一些蜥脚类恐龙在成长到能够自己填饱肚子后便会本能地“离家出走”。
研究人员在即将出版的《古地理学、古气候学、古生态学》杂志上报告了这一研究成果。（生物谷Bioon.com）
生物谷推荐原始出处：
Palaeogeography, Palaeoclimatology, Palaeoecology，doi:10.1016/j.palaeo.2009.01.002 ，Timothy S. Myers，Anthony R. Fiorillo
Evidence for gregarious behavior and age segregation in sauropod dinosaurs
Timothy S. Myersa,and Anthony R. Fiorillob
aHuffington Department of Earth Sciences, Southern Methodist University, Dallas, TX 75275, United States
bMuseum of Nature and Science, P.O. Box 151469, Dallas, TX 75315, United States
Abstract
Both body fossil and ichnofossil evidence for gregarious behavior in sauropod dinosaurs is examined. Some localities suggest that herds were partitioned on the basis of age, whereas other sites reveal groups consisting of both adult and juvenile/subadult individuals. Two skeletal accumulations showing evidence of age segregation are examined in detail. The Mother's Day Quarry in the Upper Jurassic Morrison Formation of Montana contains the remains of several immature diplodocoid sauropods. An assemblage in the Upper Cretaceous Javelina Formation of Big Bend National Park in Texas consists entirely of juvenile Alamosaurus. Both the Mother's Day and Big Bend assemblages are interpreted here as remnants of age-segregated herds. The differences between skeletal accumulations composed entirely of immature animals and mixed-age ichnological assemblages imply that herd composition was variable. When age segregation is recognized, in both fossil and modern taxa, it is thought to minimize the fitness costs related to behavioral synchronization within social groups. Age segregation of herds also contraindicates extended parental care as typical of at least some sauropod taxa.
