Water buoyancy in waterlogged environments reduced the weight of dinosaurs, creating elongated claw scratches rather than deep three-toed footprints at depths around three meters in some sites.

At certain tracksites, researchers found faint scratches and claw marks instead of full footprints, signaling near-floating movement through water rather than full walking or swimming.

Sediment context, ripple marks, and distinctions between true tracks and undertracks help differentiate swim marks from distortions caused by weight, reinforcing aquatic-associated traces.

The findings broaden our view of dinosaur ecology, showing they navigated rivers, lakes, and shallow basins and could move through changing water environments rather than staying on dry ground.

In Bolivia’s Carreras Pampa, El Molino Formation yielded about 1,400 trackways, including both footprints and swimming marks, with depth-dependent changes from deep prints to shallow scratches as water depth varied.

La Virgen del Campo in Spain revealed theropods moving through water with hind limbs paddling and only claw tips touching the bottom, suggesting a forward, gliding motion.

The shift from footprints to scratches supports the idea that increasing water depth reduced ground contact due to buoyancy, demonstrating a spectrum from walking to swimming-like locomotion.

Even light, claw-tip contact records can reveal dynamic behaviors, showing how near-floating traces contribute to reconstructing ancient dinosaur life.