Dinosaurs may not have been declining before the asteroid impact after all – new research shows that the apparent drop in species diversity could be due to gaps in the fossil record, not actual extinction trends.
Using advanced modeling techniques and deep analysis of North American rock formations, scientists found that dinosaur habitats were likely stable and that fossil discovery rates simply dropped due to fewer accessible rocks. This opens the door to the idea that if not for the asteroid, dinosaurs might still roam the Earth.
Rethinking the Dinosaur Decline
A long-standing theory suggests dinosaurs were already declining before a massive asteroid impact ended their reign 66 million years ago. But a new study led by researchers at UCL challenges that idea, arguing that the apparent drop in dinosaur diversity may be due to gaps in the fossil record, not an actual decline in species.
The study, published today (April 8) in Current Biology, examined the North American fossil record from the last 18 million years of the Cretaceous period, between 84 and 66 million years ago.
At first glance, the data – over 8,000 fossils – appear to show that dinosaur species peaked around 75 million years ago, followed by a steady decline leading up to the asteroid impact.
The Rock Record’s Hidden Bias
However, the researchers found this pattern likely reflects a decrease in fossil discovery, rather than a true drop in dinosaur populations. That’s because fewer rock formations from the final part of the Cretaceous are exposed and accessible today, making fossils from that time much harder to find.
Lead author Dr. Chris Dean (UCL Earth Sciences) said: “It’s been a subject of debate for more than 30 years – were dinosaurs doomed and already on their way out before the asteroid hit?
“We analyzed the fossil record and found that the quality of the record of four groups of dinosaur (clades) gets worse during the final 6 million years prior to the asteroid. The probability of finding dinosaur fossils decreases, while the likelihood of dinosaurs having lived in these areas at the time is stable. This shows we can’t take the fossil record at face value.
Diversity May Be Underrated
“Half the fossils we have from this time were found in North America. Our findings hint that, in this region at least, dinosaurs may have been doing better than previously suggested in the lead-up to the asteroid impact, potentially with a higher diversity of species than we see in the raw rock record.”
For the study, the research team looked at the dinosaur clades Ankylosauridae (armored herbivores such as club-tailed Ankylosaurus), Ceratopsidae (large three-horned herbivores including Triceratops), Hadrosauridae (duck-billed herbivores such as the Edmontosaurus), and Tyrannosauridae (carnivores such as Tyrannosaurus Rex).
Using Ecology Tools to Study the Past
They adopted a technique, occupancy modeling, previously used in ecology and biodiversity studies to estimate how likely a species is to inhabit a particular area.
They divided North America into a grid and, based on the geology, geography, and climate of the time, estimated how many of these grid cells the four dinosaur types likely occupied at four different times during the last 18 million years of the Cretaceous.
They found that, during this time, the proportion of land the four dinosaur clades likely occupied remained constant overall, suggesting their potential habitat area remained stable and risk of extinction stayed low.
Why Finding Fossils Got Harder
At the same time, they estimated the likelihood of the four dinosaur types being detected in each area, based on factors such as how much land is accessible to researchers (i.e., if it is covered in vegetation), how much relevant rock is exposed, and how many times researchers had attempted to find fossils from that area.
The team found that the likelihood of detection declined over the four time periods, with the most influential factor being how much relevant rock was exposed and accessible.
The researchers also found that, in contrast to the other three clades, Ceratopsian dinosaurs (such as Triceratops) were more likely to be detected later on in this period, as well as occupying more areas.
A Changing Landscape Favors the Horned
They suggested this was due to Ceratopsians favoring green plains away from rivers at a time when this kind of habitat became the main type of environment being preserved. This was due to the retreat of a large inland sea that split the continent in two and river systems feeding this sea drying up.
Co-author Dr. Alessandro Chiarenza (UCL Earth Sciences), who has previously published on end-Cretaceous dinosaur diversity and extinction, said: “If we take the fossil record at face value, we might conclude dinosaurs were already experiencing a decline before their final extinction.
Geological Forces, Not Dinosaur Demise
“In this study, we show that this apparent decline is more likely a result of a reduced sampling window, caused by geological changes in these terminal Mesozoic fossil-bearing layers – driven by processes such as tectonics, mountain uplift, and sea-level retreat – rather than genuine fluctuations in biodiversity.
“Dinosaurs were probably not inevitably doomed to extinction at the end of the Mesozoic. If it weren’t for that asteroid, they might still share this planet with mammals, lizards, and their surviving descendants: birds.”
Reference: “The structure of the end-Cretaceous dinosaur fossil record in North America” by Christopher D. Dean, Alfio Alessandro Chiarenza, Jeffrey W. Doser, Alexander Farnsworth, Lewis A. Jones, Sinéad J. Lyster, Charlotte L. Outhwaite, Paul J. Valdes, Richard J. Butler and Philip D. Mannion, 8 April 2025, Current Biology.
DOI: 10.1016/j.cub.2025.03.025
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18 Comments
Why are you using AI for the cover image when there is so much art of the extinction event
Meh, just fake up some more dinosaurs to fill in the gaps. Same old way – grab some bones from when the Ice Age, add the teeth, and get creative!
Flat-earther alert.
Loved the article. We need more of them.
Yeah, there’s a great deception for sure, but this is just more of it. The truth is that dinosaurs did not live millions of years ago, but just thousands. They existed side by side with man. The evidence is overwhelming. But delusional atheists continue to spin their fairy tales like this.
Here we go again.
While I am a believer in God, I have never accepted that “fairy tale” story called Genisis. I think of some old Rabbi sitting around a camp fire after all of the tribe just finished a Goat. When they asked the Rabbi what created them and so on, the Rabbi invented the story of Genisis. Since there was no Google to verify his story – “it stuck”!
So, you seem to have been rapped over your head with a Bible too often and you have absolutely no “open mind”.
Every atom that makes up the universe is God. He gave the “spin” of creation from the beginning. Do you think that out of the trillions of galaxies that we are the only life? I am sure God provided for life throughout the Universe. He also provided the vast spaces between everything to keep the separation.
Yeah, it’s pretty clear who’s delusional when it comes to telling geological time. Why do biblical literalists insist that reality must conform to metaphor when it’s so obvious that metaphor attempts to describe reality?
What if there’s a third option which I believe there is a way that you’re uniquely both right
You see I evolution happening until the point where God puts his spirit in Adam at the evolutionary stage that he created.
Anyhow, it is however it is and it’s all our opinions and we should still care about each other more than who is right who is wrong. And I know you believe that too I believe.
Believing the story of creation in Genesis in no way limits God from doing it ages and ages before Moses ‘put it in writing.’
You speak the truth. And that secret third option is focusing on the dinosaurs. Really fascinating stuff, this article has.
Wow, micro encephalopathy.
Dinosaur died because they could not compete with the better dinosaur the modern crocodilian the spinosauridae dinosaur spinosauridae live.archaeopteryx is true bird it has notarium like dromaeosauridae the dorsal is fuse for flapping flight and landing also found in flightless dinosaur pterosaur a aquatic animal it does not have long ankle like bird it has real knee so archaeopteryx is good flyer it also has pisiform like today good flying bird not all today bird flying bird have pisiform they only have 3 carpal .archaeopteryx has 4 carpal like the gator early mesoeucrocodylia has 6 carpal .this is archaeopteryx lithographica adult they say there 4 archaeopteryx spices the truth is one 4 carpal archaeopteryx albersdoerferi is archaeopteryx lithographic not new species juvenile subadult adult the same animal.antebrachiocarpal joint in gator chameleon dromaeosauridae archaeoteryx a flight feature .clearly mammal walker chameleon and gater are convergent evolution it’s mammal feature in mesoeucrocodilian it only happen in eusuchian mesoeucrocodilian.on perforated acetabular archosaur on researchgate academi edu.its gator acetabular is a fake it should look like orthosuchus a protosuchus pseudosuchus the gator a spinosauridae it’s too small I thought mite be salt water crocodile but it’s smaller and said it’s a gator the hip of salt water crocodile look nothing like a dinosaur or crocodile it look like a gator some none eusuchian mesoeucrocodylia acetabular look like the alligator these are early mesoeucrocodylia .new species confuciousornis has a pisiform a good flying bird it’s not new species it’s adult conficiousornis .archaeopteryx albersdoerferi has hypocledium furca for flight muscle the v furcula does not have muscle the dinosaur furcula the stick that hold up the v is hypocledium furcula allso found in early mammal that alive today no cartilage at sternum that bird feature the furcula move.
Archaeopteryx albersdoerferi the finger is fuse like today bird. dromaeosauridae probably is like that the adult.gator and chameleon lizard anterbrachiocarpal joint technology is not bird like the chameleon is better than the gator.chameleon the mammal walk lizard no sprawling.anterbrachiocarpal joint is reason they claim gator can not do bipedal even though there video of them doing bipedalism because mammal has this feature .the gator hip socket is open like theropod dinosaurs
Archaeopteryx was semi aquatic it has opisthocoelous neck vertebrae may be that the reason they do not have bird neck the opisthocoelous is gar fish and amphibian vertebrae a advance fish vertebrae allso found in compsognathus only compsognathidae has it allso in carnotaurus and some early gator type mesoeucrocodylia and compsognathus allso has platycoelous allso found in mesoeucrocodylia and pseudosuchus.opisthocoelous also found one dromaeosauridae tail there uncinate processes is diving bird they have bird type ziphodont teeth so they have land lifestyle so dromaeosauridae has aquatic bird ancestor. allso saw scientist say that archaeopteryx was aquatic and it live on a island .dromaeosauridae has mammal vertebrae not a dinosaur feature a bird feature.synsacrum is bird flight feature this on YouTube Kelly kage.bird has it with bird feature .carnotaurus ceratosaurus has it with dinosaur feature because they can not fly .convergent evolution allso for bipedal mesoeucrocodylia need it because lost all That sacral for bipedalism. mesoeucrocodylia with a synsacrum has 3 sacral today croc has 2 sacral most dinosaur has 4,5,6,.opisthocoelous allso found in a spinosaurus like spinosauridae
The super dinosaur is alive the advance eusuchian mesoeucrocodylia the modern crocodilian gator crocodile gharial.salt water crocodile acetabular is so small I could see it it was not a drawing the perforated was mark so has it .Nile crocodile actabular is hard to find on the internet I found mugger crocodile acetabular it look like alligator but hip was dinosaur but i do not like useing a advance crocodile were there is evolution.alligator mugger crocodile acetabular is dinosaur size they say Nile crocodile is bigger than usgator this is for expert the early bird look the same as dinosaur but it is not fully open for the early birds.for mugger crocodile is was not a drawing the real skeleton.some fossil mesoeucrocodylia were known for there very big acetabular
So why don’t we look beyond ourselves and compare fossil records of the period with regions elsewhere in the world where those same rock layers are more abundantly exposed?
I can tell you have absolutely no credentials to back up your theory of dinosaurs still living just thousands of years ago. I venture to say you’re a Republican too; you have that narrow-minded inability to fully grasp time relevancy. I’m a Christian, but I prefer to interpret the Bible using geological facts. God is timeless; He is the Alpha and the Omega and a day to Him could very easily be millions of years. He created man and beast on the sixth day, but in what order; the Bible does not say simultaneously. God has an incredible imagination; just read about the incredible beings with four faces and multiple eyes and wings and other fantastic creatures indicated in Revelations. That God would have created dinosaurs first and millions of years before man ON THE SAME DAY is entirely possible. Humans have a habit of interpreting the Bible and it’s sequence of events on our own terms, not understanding how incredibly vast God actually is. The Bible does not say how many years passed between the time He banished Adam and Eve and the arrive of Noah. It follows certain men and their offspring and the generations after them and it does not say when in time those men came; it must have taken hundreds of thousands of years to populate the world enough to even build cities or even learn how to. Adam and Eve lived in Paradise; they had no need to learn how to survive; God took care of them. And the Bible doesn’t say anything about Adam and Eve having children while in Paradise (but if they did, those offspring would have been fully taken care of too and clueless to any other way of living); outside of Paradise they had to learn to survive and work together from scratch. The Bible was written exclusively about the relationship between God and man, and not what may have come before, so don’t put the world and human history in human terms without considering God’s.