Scientist Claims Humans Were Meant to Live Longer, But The Dinosaurs Ruined It

A researcher from the United Kingdom believes he has unearthed compelling evidence that humans’ genetic makeup once permitted our species to live much longer.

João Pedro de Magalhães, a distinguished biologist, is the mastermind behind this groundbreaking theory.

Due to their immense size, dinosaurs ruled the Earth for over 150 million years during the Mesozoic era. However, they also had several special traits, including warm blood and the ability to thrive in varied habits, which gave them an advantage over other animals.

De Magalhães, a microbiologist at the University of Birmingham, developed the “longevity bottleneck hypothesis,” which suggests ancient mammals evolved away from longevity to ensure their species could survive amidst dinosaurs.

During the Mesozoic period, the constant threat of being prey to dinosaurs forced most mammals to accelerate their reproductive cycles. This led to the unfortunate loss of key longevity genes, showcasing a significant consequence of evolutionary pressure.

Speaking on his theory in a paper published in BioEssays, de Magalhães wrote, “My hypothesis is that such a long evolutionary pressure on early mammals for rapid reproduction led to the loss or inactivation of genes and pathways associated with long life.”

De Magalhães admits in his study that elephants, whales and humans have the potential to live fairly long lives when compared to other mammals. However, the evolution of mammals during the Mesozoic era reduced our potential longevity.

According to the microbiologist, mammals went about life in a much different way during the era of dinosaurs. Mammals were positioned much lower on the food chain, and many were nocturnal to remain out of the sight of dinosaurs.

In his paper, De Magalhães suggests that the pressure to stay alive led to the elimination of genes required for the longevity witnessed in animals such as reptiles and others with much slower biological aging processes.

In a statement, de Magalhães explained, “Some of the earliest mammals were forced to live toward the bottom of the food chain and have likely spent 100 million years during the age of the dinosaurs evolving to survive through rapid reproduction.”

After further research into his theory, de Magalhães believes he has come across evidence to suggest mammals lost certain enzymes during the Mesozoic Era, which also limited their ability to repair damage.

Despite the reproductive abilities of several animals around the world, ancient mammals did not prioritize genetic information and enzymes, as they were deemed unnecessary.

De Magalhães admits that this research is little more than a hypothesis as it currently stands. But he claims it could help scientists better understand why humans evolved as we did.

When it comes to longevity, scientists have long suspected that reptiles have an edge. Galapagos tortoises, eastern box turtles, cave-dwelling salamanders, and other reptiles and amphibians can live more than a century.

Most of the evidence highlighting the longevity of these animals has come from anecdotal reports from zoos, according to Beth Reink, a biologist at Northeastern Illinois University in Chicago, (via Popsci).

Researchers found that aging and lifespan varied greatly from one species to the next. Turtles, crocodilians, and salamanders generally aged very slowly and had disproportionately long lifespans for their size.

Reinke and her collaborators drew from long-running studies on a wide variety of animals for their study and tracked reptile and amphibian populations over an average period of 17 years.

To determine how quickly a species ages, the team calculated the rate at which individual members of these species died overtime after hitting sexual maturity. The team estimated the species’ lifespan from the number of years it took for 95% of these adult animals to die.

When compared to a group of birds and mammals with slower metabolisms that put less wear and tear on their bodies, the results of whether or not reptiles and amphibians would live longer varied.

However, one thing can not be denied: Turtles, as a group, were “uniquely slow agers,” she says.

The team also found that reptiles that lived in warm temperatures aged more quickly, while amphibians that lived in similar conditions aged more slowly.

“There are a lot of really interesting patterns that we brought to light that need to be explored further,” Reinke says.

In the Demark study, roughly 75% of the reptiles showed slow or negligible senescence while 80% aged more slowly than modern humans.

“They’re both excellent pieces of research,” Rob Salguero-Gomez, an ecologist at the University of Oxford, says. While Salguero-Gomez was not involved in any of these studies, he believes that our understanding of reptiles’ aging process is about to change.