Instead, cetaceans, the group comprising current whales and dolphins, evolved 50 million years ago from small four-legged animals carrying hooves.
Rather than being one of the greatest creatures on Earth, as they are now, they came from creatures the size of an average dog.
The discovery of 2011 by Mario Urbina and his international team contained several surprises.
"As it is the first four-legged whale skeleton of South America and the entire Pacific Ocean, this discovery was a major surprise," wrote the co-author of the study, Olivier Lambert, in an email. Lambert works at the Royal Belgian Institute of Natural Sciences. "We were also surprised by the geological age of the discovery (42.6 million years ago) and by the state of conservation [of] as many bones of most parts of the skeleton, including even a patella (patella), a few small ankle bones and the last phalanges with tiny hoof marks. "
It is the oldest known whale in this part of the world and the most complete skeleton ever discovered outside of India and Pakistan. This particular creature would have made up to 4 feet long, or 11 feet, tail included.
The team that found him named Peregocetus pacificus. It means "the traveling whale that has reached the Pacific".
Scientists knew that the body shape of whales had changed over the years, making them better adapted to life in the water. However, they did not know how the creature had moved from South Asia to South America. The early ancestors of whales were not entirely aerodynamic, unlike whales today.
"The four-legged whales, ancestors of whales and dolphins nowadays, have already been found in three main regions: the oldest geologically come from India / Pakistan, a little younger taxa. [the plural of taxonomy] have been described from North and West Africa, and even from the youngest of eastern North America, "said Lambert. On the basis of the available evidence and the fact that the post-cranial skeleton is little known in species from Africa and North America, there remained several questions to be debated: when did the quadrupeds reach the New world? What path did they take? And what [were their] locomotion abilities during this long journey? "
This 2011 discovery confirmed that the animals were probably good swimmers and able to move on land.
Unfortunately, the scientists did not find the last part of this creature's tail, but the first vertebra connecting this part of the bones was similar to that of modern beavers and otters.
The old whales also had long toes that were probably webbed, which meant that they were moving a lot like the otters of today. It's probably so that they've crossed the Atlantic Ocean, researchers said. Today, a giant otter-like creature is expected to travel a long distance to migrate, but at this time in the history of Earth, the distance between Africa and South America was twice as short and the currents strong.
From South America, they probably migrated to North America as well. According to scientists, they probably did not become fully marine animals until about 12 million years after this creature roamed the Earth.
Many milestones in this "dramatic evolutionary history" have been discovered over the years, but we still lack elements, so we need to continue to search the entire world, especially in the southern hemisphere, for skeletons of these strange four-legged whales, so that the whole scenario is better understood, "Lambert said.
Scientists will continue to dig in this region of Peru. They hope to find bones that could be even older in order to fill more pieces of this puzzle about how the whale has evolved over time.
"A skull would be great, as well as the tip of the tail," Lambert said.