Deutsche Welle (English edition)
Billions of T. rex existed on Earth, scientists reveal
A new study has calculated just how many of these ferocious dinosaurs inhabited the planet before becoming extinct.
Around 2.5 billion Tyrannosaurus rex dinosaurs existed on Earth, a new study reported Thursday.
It is the first time the total T. rex population over the estimated 2.4-million-year period that the species was on the planet has been calculated.
How scientists calculated the number
A team at the University of California, Berkeley, took into account factors including the size of the dinosaur's geographic range, its body mass, growth pattern, age at sexual maturity and life expectancy. They also estimated the duration of a
single generation and the total time that T. rex existed before extinction 66 million years ago.
The team also used a process called Damuth's law linking population to body mass: the bigger the animal, the fewer the individuals that could live at one time.
Some factors proved more difficult to estimate, meaning that the exact number of T. rex's to have lived remains uncertain.
The researchers said the total population could be as little as 140 million or as much as 42 billion. The 2.4 billion figure is a middle value.
The researchers estimated that there were approximately 20,000 adults alive at any one time.
Key T. rex facts
The T. rex was among the largest carnivorous dinosaurs. Its skull measures around 1.5 meters (5 feet) long, with massive and muscular jaws and banana-sized teeth.
According to the new study, the average adult T. rex weighed in at 4717 kilograms (5.2 tons), a male African elephant by comparison weighs between 1,800 and 6,300 kilograms.
Researchers estimate the T. rex had an average lifespan at 28 years and that the species existed on Earth for a total of 125,000 generations.
The dinosaur was spread over around 2.3 million square kilometers (890,000 square miles),
with one T. rex roughly every 100 square kilometers.
What's next?
Paleontologist Charles Marshall, who led the study published in the journal Science, said he hoped the formula used to calculate the number of T. rexs could be applied to other extinct animals in the future.
kmm/rt (Reuters, AP)
mune reaction to the administration of the anticoagulant heparin, in which the number of platelets decreases.
In the case of vaccinations, platelet factor 4 does not react to heparin, but probably to something else, suspects Berlin physician Klamroth: "It could be the vector [i.e. the transport virus]. It could be something from the spike protein. It could be something in the general immune response that combines with platelet factor 4."
How can thrombosis be properly identified?
If physicians suspect a case of thrombosis, they can diagnose the condition very quickly by a simple antibody test that responds to the heparin-platelet factor 4 complex.
This would be indicative of a platelet-activating coagulopathy, which can also typically occur as an autoimmune reaction after administration of the anticoagulant heparin. This would match with the observations from the US, where three of the patients were diagnosed this way.
H ow treated?
The most effective remedy, in addition to the administration of other anticoagulants, is highly concentrated treatment with certain lgG immunoglobulins, says Klamroth.
These specific antibodies of the immune defense serve to flood the immune system, to put it simply, and thereby displace the unwanted and harmful antia re t h ro m b o s e s bodies that trigger the thromboses.
Are all vector vaccines now under suspicion?
The fact that the phenomenon has now occurred with two vector vaccines makes medical experts wonder. "In my opinion, the fact that both vaccines are based on the same principle and cause the same problems rather suggests that the vector itself is the cause," Johannes Oldenburg of Bonn University Hospital told the German Press Agency DPA.
So far, however, no cases of thrombocytopenia with the Russian vaccine Sputnik V or the Chinese vector vaccine CanSino have been reported.
Klamroth hopes for new research results from the Greifswald immunologists: "Mr. Greinacher is continuing his research and is looking at what is associated with platelet factor 4. There are very different hypotheses [...], we are still in the dark at the moment."