Whales in the desert - page 3

The excavation site that brought Olivier all the way to Peru is exceptionally rich in fossils: “The enormous surface area is strewn with them: we find a fossil every 10 metres,” Olivier tells us. “The zone in which the desert area now lies must have been extremely shallow. Carcasses are usually deposited in shallow water. The coastal currents must have brought them there.”

The fossils are also of exceptional quality. “Sediments must have buried them quickly in the shallows. Not only are the bones well preserved, but the skeletons have remained in anatomical connection as a result.” The whale fossils are cleaned of sand, glued on site, and safely packed in plaster for transportation to the lab.

Some specimen had extremely well preserved baleens, thanks the fineness of the sand that quickly covered the corpses.

The site is also rich in archaeological remains. The team regularly finds potsherds, shells… left behind by ancient Inca peoples

Olivier is enthusiastic about the finds, particularly because they tell us a lot about the emergence of the modern whale groups. “About 35 million years ago the Archaeoceti - the first whales - made way for the second large (current) groups of whales: the toothed whales and baleen whales. With the start of the Miocene epoch in particular (23-5 million years ago), we see a whole series of modern families: true dolphins, porpoises, Monodontidae (beluga and narwhal), river dolphins, sperm whales… The initial radiation of most of these new groups occurred in the Pacific Ocean.”

And that makes this area of Peru the ideal place: “During this period the site was part of the Pacific Ocean floor, and we are finding fossils of the oldest members of these families here!”

Of the many fossils found, Olivier takes most care of the toothed whales: whales with teeth, and without baleens. “My particular area is the beaked whales,” says Olivier. ”New extant species of this mysterious family are still being discovered in remote parts of the southern hemisphere. What characterises these animals is the noticeable reduction in the number of teeth. Only one or two pairs remain, but in fully grown males these are all the more spectacular!”

The Pisco area allows Olivier to research the first members of this special group of dolphins from the Miocene period. “But we have conducted the greater part of this expedition in the desert sands,” laughs Olivier. “In February we are going back to the University of Lima to study the finds in the lab. Who knows what else we might discover!”

The wind progressively exposes the skeletons. Here you can see the different layers containing fossils, eroded by the wind