Why are dinosaurs inactive when it was cold?

Dinosaurs were likely less active in cold conditions due to their physiological and ecological adaptations. Many species are believed to have been ectothermic, relying on external temperatures to regulate their body heat, which would limit their activity during colder periods. Additionally, food sources may have been scarce in the cold, leading them to conserve energy by becoming inactive until warmer conditions returned. This behavior would have been a survival strategy to cope with harsh environmental changes.