One Tyrannosaurus rex seems scary enough. Now picture 2.5 billion of them.
That is how many of the fierce dinosaur king probably roamed Earth over the course of a couple of million years, a new study has found.
Using calculations based on body size, sexual maturity and the creatures’ energy needs, a team at the University of California, Berkeley calculated how many T-rex lived over 127,000 generations.
Photo: Reuters
The study, published in Science on Thursday, presents a first-of-its-kind estimation, but has a margin of error the size of a T-rex.
“That’s a lot of jaws,” said University of California Museum of Paleontology director Charles Marshall, the study’s lead author. “That’s a lot of teeth. That’s a lot of claws.”
The species roamed North America for about 1.2 million to 3.6 million years, meaning that the T-rex population density was small at any one moment.
There would be about two in a place of the size of Washington DC, or 3,800 in California, the study said.
“Probably like a lot of people, I literally did a double take to make sure that my eyes had not deceived me when I first read that 2.5 billion T-rexes have ever lived,” said Kristi Curry Roger, a paleobiologist at Macalester College who was not part of the study.
The estimate helps scientists calculate the preservation rate of T-rex fossils and underscores how lucky the world is to know about them at all, Marshall said.
About 100 T-rex fossils have been found — 32 of them with enough material to determine that they were adults.
If there were 2.5 million T-rex instead of 2.5 billion, we would probably have never known they existed, Marshall said.
The researchers calculated the population by using a general biology rule of thumb that says that the bigger the animal, the less dense its population.
They added estimates of how much energy the carnivorous T rex needed to stay alive, which they think is somewhere between a Komodo dragon and a lion.
The more energy required, the less dense the population.
They also factored in that T-rex reached sexual maturity at about 14 to 17 years old and lived up to 28 years.
Given uncertainties in T-rex’s generation length, range and how long they roamed, the team said that the total population could be as little as 140 million or as much as 42 billion, with 2.4 billion as the middle value.
The science about the biggest land-living carnivores of all time is important, “but the truth, as I see it, is that this kind of thing is just very cool,” said James Farlow, a geologist at Purdue University.
The collapse of the Swiss Birch glacier serves as a chilling warning of the escalating dangers faced by communities worldwide living under the shadow of fragile ice, particularly in Asia, experts said. Footage of the collapse on Wednesday showed a huge cloud of ice and rubble hurtling down the mountainside into the hamlet of Blatten. Swiss Development Cooperation disaster risk reduction adviser Ali Neumann said that while the role of climate change in the case of Blatten “still needs to be investigated,” the wider impacts were clear on the cryosphere — the part of the world covered by frozen water. “Climate change and
Poland is set to hold a presidential runoff election today between two candidates offering starkly different visions for the country’s future. The winner would succeed Polish President Andrzej Duda, a conservative who is finishing his second and final term. The outcome would determine whether Poland embraces a nationalist populist trajectory or pivots more fully toward liberal, pro-European policies. An exit poll by Ipsos would be released when polls close today at 9pm local time, with a margin of error of plus or minus 2 percentage points. Final results are expected tomorrow. Whoever wins can be expected to either help or hinder the
DENIAL: Musk said that the ‘New York Times was lying their ass off,’ after it reported he used so much drugs that he developed bladder problems Elon Musk on Saturday denied a report that he used ketamine and other drugs extensively last year on the US presidential campaign trail. The New York Times on Friday reported that the billionaire adviser to US President Donald Trump used so much ketamine, a powerful anesthetic, that he developed bladder problems. The newspaper said the world’s richest person also took ecstasy and mushrooms, and traveled with a pill box last year, adding that it was not known whether Musk also took drugs while heading the so-called US Department of Government Efficiency (DOGE) after Trump took power in January. In a
IMBALANCE: In Vietnam, a preference for boys has caused the sex ratio at birth to be 112 boys for every 100 girls, despite penalties for gender selection The number of births in Japan last year fell for the ninth consecutive year, reaching another historical low of fewer than 700,000, government data showed yesterday, as Vietnam, which is also battling to reverse a declining birthrate, scrapped its long-standing policy of limiting families to two children. Fast-aging Japan welcomed 686,061 newborns last year — 41,227 fewer than in 2023, Japanese Ministry of Health, Labour and Welfare data showed. It was the lowest figure since records began in 1899. Japanese Prime Minister Shigeru Ishiba has called the situation a “quiet emergency,” pledging family friendly measures such as more flexible working hours to
RSS