Troodon formosus, a theropod from the Late Cretaceous, is one of the few species of dinosaurs with multiple nest sites uncovered. It has been consistently demonstrated that eggs within these nests would have been partially buried in life—an exceedingly rare state in modern vertebrates. There has been debate over Troodon's capacity to engage in thermoregulatory contact incubation, especially regarding an adult's ability to efficiently supply partially buried eggs with energy. An actualistic investigation was undertaken to determine the thermodynamic efficiency of contact incubating partially buried eggs. An efficient system would keep eggs at temperatures closer to the surrogate parent than the ambient, without prohibitively high energy input. For the experiment, a surrogate dinosaur was created and used in both indoor controlled ambient temperature trials and in an outdoor variant. Even with ambient temperatures that were likely cooler than Cretaceous averages, the results showed that contact incubating partially buried eggs did seem to confer an energetic advantage; egg temperatures remained closer to the surrogate than ambient in both indoor and outdoor tests. Still, critics of contact incubating partially buried eggs are correct in that there is a depth at which adult energy would fail to make much of an impact—perhaps more relevant to buried eggs, as partially buried eggs would be in contact with an adult and likely above the thermal input threshold. Additionally, results from this experiment provide evidence for a possible evolutionary path from guarding behavior to thermoregulatory contact incubation.

中文翻译：

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古生物学家会梦想电动恐龙吗？调查恐龙接触孵化部分埋藏的蛋的假定效率低下

伤齿龙是一种来自白垩纪晚期的兽脚亚目，是为数不多的发现多个巢穴的恐龙物种之一。一直有证据表明，这些巢穴中的卵在生命中会被部分掩埋——这在现代脊椎动物中极为罕见。一直有争论伤齿龙参与体温调节接触孵化的能力，特别是关于成年人有效地为部分埋藏的卵提供能量的能力。进行了一项实际调查以确定接触孵化部分埋藏的鸡蛋的热力学效率。一个有效的系统将使鸡蛋保持在比环境更接近代孕父母的温度下，而没有过高的能量输入。在实验中，创造了一种替代恐龙，并在室内受控环境温度试验和室外变体中使用。即使环境温度可能比白垩纪的平均温度低，结果表明，接触孵化部分埋藏的鸡蛋似乎确实带来了能量优势。在室内和室外测试中，鸡蛋温度都比环境温度更接近替代温度。尽管如此，对接触孵化部分埋藏的卵子的批评是正确的，因为在一定深度，成虫的能量无法产生很大的影响——也许与埋藏的卵更相关，因为部分埋藏的卵会与成虫接触，而且很可能高于热输入阈值。此外，该实验的结果为从保护行为到体温调节接触孵化的可能进化路径提供了证据。