Perucetus colossus. Could this ancient whale dethrone the blue whale as Earth's heaviest creature?

The newly discovered beast, the Perucetus colossus, roamed the Earth approximately 37 to 39 million years ago. Its bone structure was more robust and heavier than contemporary whales, functioning as a buoyancy regulator for traversing shallow coastal waters. Despite leading a fully aquatic lifestyle, it displayed residual limbs, characteristic of ancient whales capable of short-term land mobility.

This striking information is accredited to the paleontologists who made this groundbreaking discovery in the Ica Valley in southern Peru. They intrepidly unearthed 13 vertebrae, four ribs, and a hip bone, each one massive in size. Analysis and comparisons with modern species enabled them to speculate that this leviathan could have spanned a length of 66 feet, a measure rivaling that of the blue whale. Simultaneously, its estimated weight could almost double the heft of its immediate rival.

"Dense bones naturally sink to the bottom and require constant energy to rise to the surface," explains Eli Amson, a co-author of the study hailing from the State Museum of Natural History in Stuttgart. Marine animals sport significant buoyant tissue (muscles or fats) to counterbalance this aspect. "We used a plausible ratio of skeletal tissue to other tissues for estimating the body mass," adds Amson, referring to the weight above assessment.

The findings of these paleontologists not only revise our understanding of the largest creatures to have ever lived on Earth but also implicate a reevaluation of the evolutionary history of whales. Present knowledge dictates that these marine mammals achieved their vast sizes relatively late, possibly in the past three million years. If the claims about the Perucetus colossus hold, it implies that these animals achieved mammoth body masses over 35 million years earlier.

The partial skeleton of this colossal whale was first unearthed 13 years prior. Mario Urbina from the National University of San Marcos faced the Herculean task of persuading his team that these weren't mere boulders but fossilized bones. Subsequent, more meticulous analysis vindicated his claims.

Unfortunately, additional information about the Perucetus colossus remains scarce beyond its distinctive size and habitat. Scientists agree that based solely on its skeletal structure, it is challenging to surmise what the creature consumed, although the consensus leans towards fish and crustaceans. While a herbivorous diet remains possible, such a finding would be unprecedented among whales. It is also surmised to have sported a disproportionately small head like its relative species. These findings are detailed in an article published in the journal Nature.

The absence of the entire skeletal structure hampers the formation of a comprehensive image of this species and raises questions about the weight assessment. Furthermore, the Perucetus colossus is part of an extinct lineage of whales that might have exhibited differing body proportions.

Amid these revelations, a faction of scientists remains dubious. Thus, while nothing is concrete, we can undoubtedly affirm that this whale, regardless of its exact weight, was an imposing behemoth.