Whale's ancestors are ... deer

Whales and dolphins evolved from a tiny animal with a deer-like appearance. From the mainland, they moved into the sea millions of years ago, a study has revealed.

The origin of whales has long been suspected of being 4-legged animals called artiodactyls, living on land in South Asia and gradually adapting to marine life.

Evidence for this comes from ungulate artiodactyls with even number of fingers, born before whales appear.

But until now, scientists still lack intermediate fossils that show a kinship relationship between artiodactyls and mammalian marine animals.

Researcher Hans Thewissen, an anatomy professor at Northeastern Ohio University's School of Medicine and Pharmacy, believes that they have now found new evidence of whale origin.

The sketch of Indohyus, the creature that could be the ancestor of mammal marine animals such as dolphins and whales.Photo: Jacqueline Dillard .

Accordingly, the ancestors of mammal marine animals (including whales, dolphins .) are Indohyus, a herbivore, ostensibly similar to a miniature deer and lives in the water for about 48 million years. before.

Thewissen draws this conclusion after digging through the 50-meter thick mudstone and finding hundreds of Indohyus bone fossils in Kashmir in India.

The biggest similarity between whales and Indohyus lies in the skull, ears and premolars. Indohyus' backbone also has a thick, thick outer layer that is much thicker than other animals of the same size. It is a sign that they are slow wading people.

The chemical composition of teeth also shows that this animal spends most of his time underwater.

In the past, scientists speculated that whales evolved from carnivorous artiodactyls, and gradually moved into the water to eat marine fish.

" But obviously, this is not the case, " Thewissen said.

" Indohyus is a herbivore and has lived in the water. The move to carnivorous, like today's whales still does, occurs after it moves from the land to the sea ."

In a nutshell, the new hypothesis suggests that marine mammals come from Indohyus (or another mammal close to it), gradually shifting from herbivorous diets to underwater predators, and move down to live underwater.

The findings are published today, in the journal Nature.

T. An