Sail-backed dinos had semiaquatic lifestyle

Isotopic analyses of fossils suggest crocodile-like habits

Paleontologists may have solved the mystery of how spinosaurs and tyrannosaurs — two dinosaur groups that included many large, fierce predators — could have lived in the same regions at the same time. A new study suggests that, like many pairs of surly neighbors, they simply avoided each other.

SPLISH SPLASH Oxygen isotopes in the fossilized teeth of spinosaurs hint that the creatures (shown in an artist’s reconstruction) spent much of their time in the water, as crocodiles and hippos do today.