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“Definitive” evidence of dinosaur swimming found

May 25, 2007
Courtesy Geological Society of America
and World Science staff

An un­der­wa­ter track­way with 12 claw marks pro­vides the most com­pel­ling ev­i­dence to date that some di­no­saurs swam, re­search­ers say. 

Sketch by Guillaume Suan, University of Lyon, France.


The track­way in Spain’s Cameros Ba­sin con­tains a clear rec­ord of swim­ming by a theropod—a di­no­saur of the line­age of meat-eaters with strong hind legs and short front limbs such as T. rex, sci­en­tists said.

Rubén Ez­querra of the Found­a­tion for Pa­le­on­to­lo­gi­cal Pa­t­ri­mony of La Ri­o­ja, Spain, and col­leagues found the prints in an ar­ea known for its abun­dance of di­no­saur track­ways from the early Cre­ta­ceous era, 125 mil­lion years ago. 

The find­ings are re­ported in the June is­sue of the re­search jour­nal Ge­ol­o­gy.

The 15-meter (49-foot) track­way con­sists of six pairs of two to three scratch marks each, pre­served in sand­stone.

Scratch marks said to be left by a swimming theropod.


Ac­cord­ing to co-author Loic Cos­teur of the Un­ivers­ity of Nantes, France, the S-shaped prints in­di­cate a large float­ing an­i­mal claw­ing the sed­i­ment as it swam in about 3.2 me­ters (3.5 yards) of wa­ter. 

Rip­ple marks on the sur­face of the site in­di­cate the di­no­saur was swim­ming against a cur­rent, strug­gling to go straight, he added. “The di­no­saur swam with al­ter­nat­ing move­ments of the two hind limbs, a pel­vic pad­dle swim­ming mo­tion,” said Cos­teur. 

“It is a swim­ming style of am­pli­fied walk­ing with move­ments si­m­i­lar to those used by mod­ern bipeds, in­clud­ing aquat­ic birds.”

Wheth­er di­no­saurs could swim has been re­searched for years, but lit­tle hard ev­i­dence ex­isted un­til now, sci­en­tists said. Large, pre­da­tory mar­ine rep­tiles did prowl the seas dur­ing the di­no­saur era; but these were re­la­tive­ly dis­tant re­la­tives of true di­no­saurs.

“The track­way at La Vir­gen del Cam­po opens the door to seve­ral new ar­e­as of re­search,” said Cos­teur. “New biome­chan­i­cal mod­el­ing will in­crease our un­der­stand­ing of di­no­saur phys­i­ol­ogy and phys­i­cal ca­pa­bil­i­ties, as well as our view of the ec­o­log­i­cal niches in which they lived.”


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An underwater trackway with 12 claw prints provides the most compelling evidence to date that some dinosaurs swam, researchers say. The trackway in Spain’s Cameros Basin contains a long, continuous record of swimming by a theropod—a dinosaur of the lineage of meat-eaters with strong hind legs and short front limbs such as T. rex, scientists said. Rubén Ezquerra of the Fundación Patrimonio Paleontológico de La Rioja in La Rioja, Spain, and colleagues found the prints in an area long known for its abundance of dinosaur trackways dating from the early Cretaceous era, 125 million years ago. The findings are reported in the June issue of the research journal Geology. The 15-meter (49-foot) trackway consists of six pairs of two to three scratch marks each, preserved in sandstone. According to co-author Loic Costeur of the University of Nantes, France, the S-shaped prints indicate a large floating animal clawing the sediment as it swam in about 3.2 meters (3.5 yards) of water. Ripple marks on the surface of the site indicate the dinosaur was swimming against a current, struggling to go straight, he added. “The dinosaur swam with alternating movements of the two hind limbs, a pelvic paddle swimming motion,” said Costeur. “It is a swimming style of amplified walking with movements similar to those used by modern bipeds, including aquatic birds.” Whether dinosaurs could swim has been researched for years, but little hard evidence existed until now, scientists said. “The trackway at La Virgen del Campo opens the door to several new areas of research,” said Costeur. “New biomechanical modeling will increase our understanding of dinosaur physiology and physical capabilities, as well as our view of the ecological niches in which they lived.”