Perucetus Colossus: Recorded Largest Animal of All Time Could be Impossible, Paleontologists Argue

Perucetus colossus is an extinct whale species whose 39-million-year-old fossil was discovered by scientists in Peru. Its historical reveal also led to the designation that the prehistoric creature could be the largest animal of all time. It was also reported that P. colossus even surpassed the blue whale (Balaenoptera musculus) in terms of weight and length. However, new research shows the gargantuan Peruvian whale could be morphologically impossible.

The largest living animal on Earth is the blue whale and scientists have concluded that B. musculus is also the biggest mammal to have ever existed. The longest blue whale specimen recorded was over 110 feet and 17 inches in length. Furthermore, the heaviest blue whale weighed approximately 190 tons, which is equivalent to 30 elephants or 2,500 humans, according to the organization Whale and Dolphin Conservation.

Given the morphological features of the blue whale, findings about P. colossus means that the animal kingdom's heavyweight contender pushes the boundaries of vertebrate morphology, according to a study last year. The initial findings about the extinct whale confirms previous fossil record that some terrestrial animals were able to adapt and evolve to a fully aquatic lifestyle, just like whales.

Perucetus Colossus

In the study published in the journal Nature in August 2023, researchers confirmed that whale evolution involves a substantial increase of their maximum body size in an elongated pattern. In their assessment, scientists described that Perucetus colossus (a basilosaurid whale) from the middle Eocene epoch of Peru possess a skeletal mass that exceeded any known aquatic or mammal vertebrate. This makes the it the largest creature of all time.

The confirmed discovery of P. colossus was only made last year but the initial discovery of its fossils in the Peruvian desert occurred more than 10 years ago. It was previously designated as an unknown species but succeeding assessments show that the species belong to the extinct genus of early whale called Perucetus. The extinct ancient marine mammal species likely lived almost 40 million years ago, according to scientists.

Downsizing Perucetus Colossus

Despite the designation of Perucetus colossus as the largest animal of all time, a new study earlier this year shows otherwise. In the research paper published in the journal Paleontology and Evolutionary Science on February 29, scientists 'downsized the heavyweight' by revising weight estimates of the giant fossil whale P. colossus. The conclusion is based on factors and methodological approaches used by the researchers.

According to the February 2024 study, some of the basis for the downsizing of the P. colossus is based on the following parameters or evidence below:

• various data sources coming from large extant cetaceans
• comparing published body mass estimates with body outlines
• weighing in isometry between skeletal and body masses
• addressing the issue of method-dependent error rates
• correlating Perucetus with known physiological and ecological limits of living whales