【古生物学】恐竜の営巣戦略は生息分布に影響を与えたか

The use by dinosaurs of specific materials and techniques in nest building, which influenced incubation heat, may have affected where they were able to live, according to a study in Scientific Reports.

Kohei Tanaka and colleagues found that different clades of dinosaur preferred different materials for nest-building; some used soil or plant materials to build mounds whereas others dug holes in the sand in which they laid their eggs. The holes, which were favoured by some sauropods, relied mainly on heat from sunlight to incubate eggs. Their temperature was only slightly higher than air temperature. Other sauropods and hadrosaurs preferred mounds made of soil and plants that were heated by microbes as they decayed organic matter, making them significantly warmer than the surrounding air.

In order to better understand the implications of dinosaur nesting habits, the authors looked at the nesting strategies of living animals such as crocodiles and birds to assess whether certain types of nest could have been used by dinosaurs in cooler climates. The authors also compared existing data on dinosaur nests, eggs and eggshells to determine whether dinosaurs preferred certain materials to build covered nests. The comparisons suggest that the relationship between nest types, nest building materials, and heat sources for incubation that can be observed in living animals may give clues about nesting habits in extinct, non-avian dinosaurs. The authors conclude that the built mounds potentially allowed the dinosaurs that built them to reproduce in colder, more northerly climates, such as the Arctic, and that the dinosaurs’ preferred nesting style may have played a role in where they were able to live.