We thought the blue whale was huge. Until we found Colossus, the heaviest animal in history
“Many scientists did not believe in the existence of this animal, because an animal with such great bone density had never been discovered”
Never has a nickname been more apt.
When it came to finding a name for the new primitive cetacean discovered in the desert of the Ica Valley in southeastern Peru, the paleontologists who participated in the discovery opted for a form that was as simple and obvious as it was obvious: Perucetus Colossus.The first is an indication of the place where it was found. The second, “Colossus”, a label that alludes to its enormous dimensions, so huge that it has already been presented as the heaviest animal known and is also a sure candidate to be the heaviest animal that has ever walked or swam on Earth. .by its seas.
What have we found? Some bones. Fascinating, yes. 13 years ago, Chilean paleontologist Mario Urbina discovered the first bones of what would eventually be revealed. Perucetus Colossusan ancestor related to dolphins and whales. The fossils attracted the attention of scientists and during the last decade they continued to study them and promote excavation campaigns until obtaining a “small” treasure, which is now in the Natural History Museum of Lima (UNMSM): 13 vertebrae, four ribs and part of a pelvis.
It’s not a complete skeleton and the skull is still missing, but it has helped experts get an idea of what the creature looked like.
conclusion? Giovanni Bianucci of the University of Pisa explains: “Although the skeleton we studied is not complete, rigorous estimates based on measurements of the preserved bones and comparisons with a large database of present-day and fossil organisms indicate that the skeleton was largely intact.” Perucetus Colossus It weighed between five and eight tonnes, at least twice as much as the largest living animal, the blue whale.” The data is astonishing, but it is by no means the only conclusion they reached.
What else? This ancient cetacean – whose bones were discovered in 39 million year old rocks in the Ica desert – could reach a length of 20 meters and an astonishing body mass, which would range between a minimum of 80 tons and a maximum of 340 tons. These are fascinating data, far greater than those of the great creatures known so far.
Although they can be somewhat larger and reach 30 meters, blue whales rarely exceed 150 tons. The WWF states that some specimens Balaenoptera musculus intermediate They can reach 180, but even that figure is small in comparison Perucetus Colossus, ArgentinosaurusOne of the largest land animals recorded to date, it also weighed quite a lot: 70 tons. The data may vary between specimens, but as the University of Lima clarifies, it exceeded a maximum weight of 340 tons PerucetusCalculations point to a standard of about 200 tonnes.
Can we imagine this? We can do even more. The researchers summarized their findings in an article published in the journal Nature And both the UNMSM and the University of Pisa have published a collection of images that help us understand what is going on Perucetus Colossus,
And it includes both photographs of its vertebrae and drawings that reconstruct what it might have been like. Undoubtedly, there’s work ahead. Paleontologists haven’t yet recovered relevant pieces of its skeleton, such as the skull, so that hasn’t stopped them from suggesting that Colossus may have been a scavenger that ate food found on the ocean floor, such as buried animals.
And how was his body? One of the specialties of Perucetus What can be seen in the scientific illustrations is that it would have had front limbs for walking on the sea floor and others, smaller and vestigial, located on the hind end. Small hind legs are found in other basilosaurids, the family of archaic cetaceans that includes the creature discovered in the Ica Valley. Scientists have also looked at their bone tissue and how compact and dense their bones are, a feature less clearly found among sea cows today.
Can we go further? Yes. For example, due to their experience and available data, scientists speculate that his special skeleton can give such Perucetus Colossus It needed stability to live in turbulent waters, to stay close to the coast and where it could feed on the carcasses of other marine vertebrates. What is clear is that the weight of cetaceans represented a challenge for paleontologists, who had to deal with heavy vertebrae: the lightest of all weigh more than 100 kilograms.
To reach the bones, scientists had to break several meters long rocks in a remote area.
How was the announcement received? “It was an unexpected discovery. Many scientists did not believe in the existence of this animal, since an animal with such a great bone density had never been discovered,” says Rodolfo Salas, from the Department of Paleontology at the MHN. At first, in fact, it was believed that the bones were rocks, something that turned out to be false after studying them in the laboratory.
Regarding its age, thanks to the study of plankton species and volcanic ash found in the area of discovery, experts from the University of Milano-Bicocca have concluded that the fossil is between 39.8 and 37.84 million years old. Conclusion: Perucetus Colossus Lived in the Eocene, “when the ancestors of present-day cetaceans abandoned the terrestrial lifestyle in favor of a marine one,” note Elisa Malinverno and Guilia Bosio.
Why is it so important? For several reasons. The first and most obvious is that it’s not every day that one can announce the discovery of a “giant” cetacean, a solid candidate for being the heaviest animal ever. The second may be less impressive, but just as important: it opens up an interesting avenue of research into when gigantism arose in the sea.
“In general terms, gigantism known so far among aquatic tetrapods has evolved within pelagic and active swimmers. Here we describe Perucetus ColossusA basilosaurid whale from the Middle Eocene of Peru,” studied by Natureand elaborates about the new creature: “The peak body mass of cetaceans was already reached 30 million years earlier than previously estimated in a coastal context.”
Images | Università di Pisa and UNMSM 1 and 2
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*An earlier version of this article was published in August 2023