Dinosaurs May Have Eaten Seaweed Research

Recent research published in Frontiers in Ecology and Evolution on August 6, 2026, reveals that dinosaurs and other Cretaceous animals living near ancient coastlines consumed food derived from the sea, pointing strongly to seaweed consumption. Led by Dr. Clayton Forster at the University of Arkansas, scientists examined chemical signatures preserved in fossil teeth from North American coastlines. The researchers analyzed carbon isotope ratios, specifically measuring lighter carbon 12 and heavier carbon 13 expressed as δ13C values, in fossil specimens from sites bordering the Western Interior Seaway and the ancient Gulf of Mexico. Coastal fossils consistently exhibited higher δ13C values compared to landlocked formation fossils, indicating marine subsidization across food webs. The findings demonstrate that terrestrial organisms in Cretaceous greenhouse climates relied on marine resources to supplement their diets. Given that few organisms besides marine macroalgae or macrophytes match the criteria of remaining available over millions of years along coasts, researchers concluded that large coastal herbivores likely ate seaweed. This study bridges gaps between terrestrial and marine ecosystems, emphasizing their deep intertwinement over hundreds of millions of years. The insights highlight the importance of environmental linkages across time and space, prompting further research into polar or equatorial latitudes and different geological periods.