Large dinosaurs, especially sauropods, were so heavy they lived primarily in swamps and water to support their weight.
Paleontological evidence including fossilized trackways, bone stress analysis, and biomechanical modelling shows that most large dinosaurs were fully terrestrial. Sauropods had skeletal features adapted for weight-bearing on land, including columnar limbs and reinforced vertebrae. Trackways demonstrate they walked across diverse terrain types. The outdated notion that sauropods needed water-born support stemmed from early assumptions about reptilian locomotion. Skeletal proportions indicate sauropods were similar to modern large terrestrial mammals in their weight-bearing capabilities.