New evidence to help solve how earliest birds took flight

University of Southampton

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An illustration of Archaeopteryx.

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Credit: Mark Witton

The first ever bird to inhabit the Earth used its robust hind legs to make two or three powerful leaps while flapping its way to flight, according to a study by the University of Southampton.

Scientists have debated for over a century how Archaeopteryx – a 150 million year old reptile-like bird – was able to take-off into the air.

The creature, which represents an important evolutionary step between non-avian dinosaurs and birds, was incapable of achieving flight with just a single jump as modern birds do.

Archaeopteryx had limited shoulder mobility and no breastbone, which hampered its ability to quickly reach flight speed. Exactly how it left the ground has, until now, remained a puzzle.

“Archaeopteryx is the first real bird,” explains palaeobiologist at the University of Southampton, Dr Neil Gostling. “It was covered in feathers and possessed wings, but also retained a number of distinctly dinosaur features, such as a long bony tail, claws on separate fingers, and teeth in a beakless jaw. It wasn’t a particularly well developed ‘bird’ compared to those we know today.”

Professor of Biomechanics at Southampton, Markus Heller, adds: “We know Archaeopteryx couldn't rely on its wings to take off – with no keeled sternum, and a shoulder that couldn't lift the wing above the back – so we asked what its legs could contribute. It turns out that is where take-off is won: the legs generate the force, and the wings take over afterwards.”

Several mechanisms for how early birds first left the ground have been suggested over the years, including flapping while running up an incline, and gliding from a height – for example from a tree, or a cliff.

These methods are difficult to test experimentally, but following observations made by the late Dr Colin Palmer, the team combined sophisticated computer modelling with these observations from living birds, such as gulls, magpies, crows and finches, and fitted this to Archaeopteryx’s anatomy. By analysing joint moments at the hip, knee, and ankle, alongside muscle capacity, they estimated the ancient bird’s take-off velocity.

The scientists, including Dr Pauline Provini from the Muséum National d’Histoire Naturelle in Paris, concluded that Archaeopteryx could have achieved its minimum sustainable flight speed in as few as two or three leaps, without requiring the energetically demanding single leap used by modern birds.

“Our findings show that a mid-sized, 400g Archaeopteryx could have achieved a sustainable flight speed of seven metres per second with three bipedal leaps, or with two bipedal leaps with a downward flap between jumps.” said Dr Erik Meilak, a former PhD researcher at the University of Southampton who carried out the study.

“All birds push with their legs when they take-off,” explains Dr Gostling. “In fact up to 90 percent of the force required to get off the ground comes from the legs and then the wings take over.

“Archaeopteryx would have either taken off with a leap, leap, leap and then lots of flapping, or a leap, a flap, another leap and more flapping.

“Although today’s birds can take-off with just one leap, we still see many, such as crows, magpies and seagulls, also using the multiple hop technique. They use one leap if startled, stressed or threatened, or – like their ancestors – two or three or more if they are saving energy.”

The researchers findings are published in the journal Developmental Biology.

Ends
 

Notes to editors
 

1. The paper ‘Hop, hop and away: On the take-off of Archaeopteryx using a multiple leaping mechanism’ is published in the journal Developmental Biology, DOI 10.1016/j.ydbio.2026.07.018 and can be read here: https://doi.org/10.1016/j.ydbio.2026.07.018
    
2. For interviews or more information contact Peter Franklin, Media Manager, University of Southampton. press@soton.ac.uk +44 23 8059 3212 or Dr Neil Gostling, n.j.gostling@soton.ac.uk 07528 498792.
    
3. Images can be downloaded here: https://safesend.soton.ac.uk/pickup?claimID=KtrxWv8XRahx9FpN&claimPasscode=Khyf3nAJddcwMn3a&emailAddr=286425
    
4. Authors on the paper are: Dr Erik Meilak, Dr Neil Gostling, Dr Colin Palmer and Professor Markus Heller, all of the University of Southampton, UK, and Dr Pauline Provini of the Muséum National d’Histoire Naturelle in Paris, France.
    
5. This Manuscript is of even more importance to the authors because Dr Colin Palmer passed away at the end of last year, and this project came about with him at the centre. A photo of Colin is available.
    
6. For more about Biological Sciences at the University of Southampton visit: https://www.southampton.ac.uk/about/faculties-schools-departments/school-of-biological-sciences
    
7. The University of Southampton drives original thinking, turns knowledge into action and impact, and creates solutions to the world’s challenges. Our academics are leaders in their fields, forging links with high-profile international businesses and organisations, and inspiring a 25,000-strong community of exceptional students, from over 135 countries worldwide. Through our high-quality education, the University helps students on a journey of discovery to realise their potential and join our global network of over 300,000 alumni. www.southampton.ac.uk

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Journal

Developmental Biology

DOI

10.1016/j.ydbio.2026.07.018 

Method of Research

Observational study

Subject of Research

Animals

Article Title

Hop, hop and away: On the take-off of Archaeopteryx using a multiple leaping mechanism

Article Publication Date

15-Aug-2026

 

An illustration of how Archaeopteryx could have taken off.

Credit

Science Graphic Design

 

A model of Archaeopteryx.

Credit

Karen Fawcett

Were there tiny dinosaurs? New study explores one of evolution’s biggest mysteries

Mathematical models reveal that even the smallest dinosaurs were surprisingly large—and suggest that flight allowed birds to break the rules

American Museum of Natural History

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A model of Microraptor being put on display at the American Museum of Natural History. Microraptor was one of the smallest known dinosaurs, weighing about one pound—roughly the size of a large rabbit.

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Credit: Alvaro Keding / ©AMNH

Dinosaurs are famous for being big, from the towering Tyrannosaurus rex to the colossal Apatosaurus. But a new study published today in the journal Evolution by scientists at the American Museum of Natural History and Princeton University suggests that one of the greatest mysteries of dinosaur evolution isn’t how some species became giants—it’s why even the smallest dinosaurs never became truly tiny.

Using mathematical models to investigate the evolution of body size across vertebrates, researchers found that while energetics and physiology can explain the sizes of mammals, birds, and turtles, they cannot explain why the smallest non-bird dinosaurs remained unusually large throughout their evolutionary history. Instead, the findings suggest that competition with small-bodied early mammals may have prevented dinosaurs from becoming mouse- or sparrow-sized animals that are so common among vertebrates today.

“Everyone loves a giant dinosaur,” said study co-author Roger Benson, the Macaulay Curator of Dinosaur Paleobiology at the Museum. “But we decided to look at the other end of the scale. The absence of tiny dinosaurs may be just as interesting as the existence of giant ones. We already knew that dinosaurs prevented mammals from evolving to large sizes before the end-Cretaceous mass extinction. Here we suggest that mammals in turn prevented dinosaurs from evolving to small sizes.”

While the largest dinosaurs weighed more than 80 tons, the smallest known non-bird dinosaurs weighed nearly one pound (approximately 450 grams)—about the size of a large rabbit. This is more than 200 times larger than the world’s smallest bird, the bee hummingbird, which weighs just 1.75 grams and the smallest mammal, the Etruscan shrew, which is about 1.8 grams. The smallest lizard, the dwarf gecko, is only 0.15 grams.

Roughly 75 percent of living mammal species and 90 percent of living bird species are smaller than the smallest non-bird dinosaurs.

“Small animals dominate modern ecosystems,” said Stephanie Lechki, the lead author of the study and a postdoctoral fellow at Princeton University. “If we want to understand how today’s biodiversity evolved, we need to understand why tiny dinosaurs appear to have been missing.”

One possible explanation is simply that scientists haven’t found fossils of the smallest dinosaurs. Tiny animals are harder to discover, and their delicate bones are less likely to fossilize. But Benson and Lechki argue that explanation is unlikely because fossil deposits that preserve dinosaurs routinely preserve much smaller animals as well, including mammals, lizards, amphibians, and other vertebrates. If mouse-sized dinosaurs had existed, scientists would expect at least some of them to appear alongside these other small animals.

Instead, the fossil record suggests that genuinely tiny non-avian dinosaurs were rare, or maybe they were absent altogether.

To investigate why, the researchers used mathematical models that predict how natural selection shapes body size, based on the physiology of energy uptake and reproduction. These models are based on the idea that animals should evolve into sizes that help them most efficiently turn energy into offspring.

This approach successfully predicted observed body size distributions of mammals, birds, and turtles, but it did not work for snakes, lizards, and crocodilians. And even after accounting for a wide range of physiological possibilities, the models could not explain why most non-avian dinosaurs were so much larger than expected.

The findings suggest that physiology alone cannot explain dinosaur body sizes. Instead, ecological factors—including competition, predation, and the availability of different ecological niches—likely played a large role in limiting how small non-avian dinosaurs could become.

The study also offers new insight into one of the most dramatic transitions in vertebrate evolution: the emergence of birds. Although birds evolved from dinosaurs, modern birds are dramatically smaller than even the smallest known non-avian dinosaurs. Birds evolved body sizes far smaller than any other group of dinosaurs in just a short time after they first appeared in the Early Cretaceous.

The researchers found that this shift toward miniature body sizes also cannot be explained by physiology alone. Instead, they propose that the evolution of powered flight fundamentally changed the ecological opportunities available to early birds. By taking to the air, birds may have escaped the ecological constraints that prevented their dinosaur ancestors from evolving into much smaller animals.

“The ability to fly may have opened entirely new ways of life,” Lechki said. “Once birds entered those new ecological niches, they were free to evolve body sizes that had simply not been possible for other dinosaurs.”

Future studies may reveal even more about the ecological pressures that determined which body sizes flourished and which never evolved at all.

“We have this unusual situation where the ancestors of dinosaurs could be tiny. The living descendants of dinosaurs—birds—they can be tiny. But dinosaurs themselves seemed to be forbidden from being tiny,” Benson said. “And we don’t really understand that yet, but it’s a question we should continue to explore if we really want to understand dinosaurs and their fascinating biology.” 

Study DOI: 10.1093/evolut/qpag117

 

ABOUT THE AMERICAN MUSEUM OF NATURAL HISTORY (AMNH)

The American Museum of Natural History in New York City, founded in 1869 with a dual mission of scientific research and science education, is one of the world’s preeminent scientific, educational, and cultural institutions. The Museum encompasses more than 40 permanent exhibition halls, galleries for temporary exhibitions, the Rose Center for Earth and Space including the Hayden Planetarium, and the Richard Gilder Center for Science, Education, and Innovation. The Museum’s scientists draw on a world-class permanent collection of more than 30 million specimens and objects, some of which are billions of years old, and on one of the largest natural history libraries in the world. Through its Richard Gilder Graduate School, the Museum offers two of the only free-standing, degree-granting programs of their kind at any U.S. museum: the Ph.D. program in Comparative Biology and the Master of Arts in Teaching (MAT) Earth Science residency program. Visit amnh.org for more information.

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Journal

Evolution

DOI

10.1093/evolut/qpag117 

A fossil of Microraptor, one of the smallest known dinosaurs. 

Credit

Mick Ellison / ©AMNH

 

New species of dinosaur, a cousin of Velociraptor, probably glided on four “wings” and hunted early birds

Field Museum

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The new microraptor dinosaur Jian changmaensis (left) attacks the early bird Gansus yumenensis (right) in what is now the Changma Basin of northwestern China approximately 120 million years ago. Credits: illustration by Lewis LaRosa, colorized by Jão Canola.

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Credit: Credits: illustration by Lewis LaRosa, colorized by Jão Canola.

A fossil bed in northwestern China is littered with the remains of hundreds of prehistoric birds—including some whose broken bones were crushed into pellets, similar to those coughed up by modern owls. For years, scientists guessed that a larger predatory animal must have hunted these ancient birds, but they never found direct fossil evidence of this predator. But in a new paper published in the Annals of Carnegie Museum, researchers announced the discovery of a new species of dinosaur from this fossil bed—a cousin of Velociraptor with long feathers on its front and back limbs. Based on the dinosaur’s distinctive arm and shoulder bones, scientists hypothesize that this animal is the missing predator.

“Scientists have found these weird, broken-up clusters of bird bones at this site, and we didn’t know what made them. This new microraptor dinosaur, Jian changmaensis, is our best guess,” says Jingmai O’Connor, the associate curator of fossil reptiles at the Field Museum in Chicago and senior author of the paper describing the new species. “It’s the only dinosaur found at this site that wasn’t a bird, it was a carnivore, and it was much bigger than everything else that we’ve found there.”

Modern birds are the only group of dinosaurs that survived the after-effects of a meteorite hitting the Earth 66 million years ago. But birds and their fellow dinosaurs lived together for tens of millions of years in the Jurassic and Cretaceous periods. One group of dinosaurs, the dromaeosaurs, were close cousins of the bird-dinosaurs. Dromaeosaurs, like birds, were covered in feathers and tended to be relatively small and speedy. The Velociraptors made famous in Jurassic Park are probably the most famous dromaeosaurs (but they would have been smaller and more feathery than they're depicted in the movies).

The new species, Jian changmaensis, belongs to a clade within the dromaeosaur family called microraptors. Microraptors tended to be small; the most well-known species is about the size of a crow. “Jian is one of the biggest microraptor specimens that has ever been found,” says O’Connor. “The piece of its upper arm bone that we have is about 4 inches long, so the entire dinosaur probably had something like a four-foot wingspan, around the size of a barn owl.”

And while scientists only have Jian’s arm, they suspect that Jian, like its fellow microraptors, had long feathers on both its arms and its legs, giving it the appearance of having four “wings” that it used to glide. “Jian and the other microraptors probably weren’t capable of true, powered flight, but they could probably glide like a flying squirrel,” says O’Connor.

The new dinosaur’s name, Jian changmaensis, is a reference to its bird-like appearance and its place of origin. Jian is a winged creature in Chinese mythology, and the fossil was found in the Changma Basin in China’s Gansu province.

“Jian changmaensis reveals that non-avian dinosaurs lived in what is now the Changma Basin, an area famous for its fossil birds,” says Matt Lamanna, corresponding author of the study and  Carnegie Museum of Natural History’s Mary R. Dawson Curator of Vertebrate Paleontology and senior dinosaur researcher. “Our team has recovered more than a hundred bird fossils at Changma, but only this single non-avian dinosaur specimen. Jian provides critical new insight into the biological history of the Changma region and the ecological context of the ancestors of today’s birds.”

“You cannot understand life on the planet today without looking at its origins,” says O’Connor. “Birds are arguably the most successful group of land-dwelling vertebrate animals on Earth today. Learning about early birds and their close non-bird dinosaur relatives gives us a better understanding of what made the group of birds that survived so special.”

This study was contributed to by Ling-Qi Zhou (Gansu Geological Museum), Matthew Lamanna (Carnegie Museum of Natural History), Ashley Poust (University of Nebraska State Museum and University of California Museum of Paleontology), Da-Qing Li (Gansu Agricultural University), Hai-Lu You (Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences), and Jingmai O’Connor (Field Museum).

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Figure 2 from Zhou et al paper, showing the arm bones of the new dinosaur Jian.

Credit

Zhou et al

Journal

Annals of Carnegie Museum

Article Title

FIRST NON-AVIAN THEROPOD (DROMAEOSAURIDAE, MICRORAPTORINAE) FROM THE BIRD-BEARING LOWER CRETACEOUS XIAGOU FORMATION OF THE CHANGMA BASIN, GANSU PROVINCE, NORTHWESTERN CHINA

Article Publication Date

4-Jun-2026

DENTAL FOSSILS NOT DENTAL FLOSS

Dinosaur dental fossils reveal bird-like parental care bonds

Tooth patterns reveal complex nurturing behavior, study says

Ohio State University

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COLUMBUS, Ohio – Baby dinosaurs were likely fed more nutritious food than their adult counterparts, a finding that could offer insights into their social evolution, suggests a new study. 

Paleontologists uncovered this finding by studying wear on the fossilized teeth of Maiasaura peeblesorum, a duck-billed dinosaur species that lived about 75 to 80 million years ago during the Late Cretaceous. First discovered in Montana, these large, herbivorous dinosaurs lived in herds and were thought to have been highly social creatures, especially in contrast to those that may have had different reproductive strategies. 

Extensive fossil findings of preserved Maiasaura nests have since made them a key species for understanding the reproductive behaviors and ecology of many other types of duck-billed dinosaurs. Now, closer analysis of their dental wear patterns has revealed that while juvenile Maiasaura teeth had significantly more crushing wear, adults exhibited more shearing wear, suggesting parents could have been bringing softer, higher-protein food to their children than they themselves ate. 

Today, this behavior is typical of birds whose young are confined to the nest for a time after hatching, said John Hunter, lead author of the study and an associate professor in evolution, ecology and organismal biology at The Ohio State University, meaning that these dinosaurs could have exhibited a level of parental care unusual for most species on Earth at the time.  

“The urge for a bird to feed a youngster is a very old behavior,” said Hunter. “What we’re providing is that evidence for that behavior probably goes much further than the origin of birds, perhaps to the origin of dinosaurs.”

Learning more about which social behaviors may have endured throughout evolutionary history can give scientists a better glimpse into how organisms made a living tens of millions of years ago, as well as help predict traits modern animals might pass on to their descendants. 

The study was recently published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.

Researchers specifically detail that juvenile Maiasaura likely ate more nutritious low-fiber foods like fruit while their caretakers consumed a greater proportion of tougher, nutritionally poor high-fiber plant parts. In mammals today, the same patterns of shearing wear would likely be present in grazers like horses, antelopes and cows, while low-fiber diet eaters like tapirs would have dental patterns similar to the young dinosaurs. 

In comparing the types of wear on dinosaur teeth, researchers also suggested that shifts in diet may have also performed an important role in early growth and development. In this instance, their results show that the diet of juvenile Maiasaura may have caused them to grow particularly fast in their first year.

The study also considers other interpretations of their results. Instead of consuming completely different fare, dinosaur parents could have been feeding their young partially regurgitated food, yet another behavior now common in birds. Alternatively, juveniles could also have left the nest to forage for themselves, an activity now seen in modern herbivorous lizards.  

While that solution is less likely as juveniles were helpless, and probably dependent on their parents to feed them during the first weeks after hatching, learning more about their remains can widen scientists’ perspectives of what sophisticated biological and social systems dinosaurs may have had, said Hunter. 

“The further back in time you go, the less of a fossil record you have, so paleontologists have to draw from different sources of inspiration from different parts of the living,” he said. “So even among closely related dinosaurs, there is probably still quite a bit to learn about them.”

If possible, future studies could examine other fossils of the very youngest dinosaurs for dental microwear to test other hypotheses regarding dinosaur embryos and hatchlings.

Christine Janis from the University of Bristol and the University of Brown was a co-author. This work was supported by Brown University.

#

Contact: John Hunter, Hunter.360@osu.edu

Written by: Tatyana Woodall, Woodall.52@osu.edu

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Journal

Palaeogeography Palaeoclimatology Palaeoecology

DOI

10.1016/j.palaeo.2026.113707 

Method of Research

Case study

Subject of Research

Animals

Article Title

Tooth wear in juvenile and adult hadrosaurs: implications for parental care in Maiasaura☆

Article Publication Date

15-May-2026

 

Researchers show dinos hatched eggs less efficiently than modern birds

Research using dinosaur body model suggests that – unlike modern birds – bird-like dinosaurs may have used the sun’s warmth to help hatch eggs, shedding light on the evolution of avian-style incubation.

Frontiers

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Lateral view of the clutch. The eggs were molded from casting resin. 

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Credit: Chun-Yu Su.

What do we really know about how oviraptors – bird-like but flightless dinosaurs – hatched their eggs? Did they use environmental heat, like crocodiles, or body heat from an adult, like birds? In a new Frontiers in Ecology and Evolution study, researchers in Taiwan examined the brooding behavior and hatching patterns of oviraptors. They also modelled heat transfer simulations of oviraptor clutches and compared hatching efficiency to modern birds. To do so, they experimented with a life-sized oviraptor incubator and eggs.

“We show the difference in oviraptor hatching patterns was induced by the relative position of the incubating adult to the eggs,” said senior author Dr Tzu-Ruei Yang, an associate curator of vertebrate paleontology at Taiwan’s National Museum of Natural Science.

“Moreover, we obtained an estimate of the incubation efficiency of oviraptors, which is much lower than that of modern birds,” added first author Chun-Yu Su, who attended Washington High School in Taichung when the research was conducted.

Building a dinosaur

The reconstructed oviraptor Heyuannia huangi lived between 70 and 66 million years ago in what today is China. Estimated to be around 1.5 meters long and weighing around 20kg, it built semi-open nests made up of several rings of eggs.

The incubating oviraptor’s trunk was made from polystyrene foam and wood for the skeletal frame and cotton, bubble paper, and cloth for the soft tissue. Eggs were molded from casting resin. In the two clutches used in the experiments, eggs were arranged in double-rings based on real oviraptor clutches.

“Part of the difficulty lies in reconstructing oviraptor incubation realistically,” said Su. “For example, their eggs are unlike those of any living species, so we invented the resin eggs to approximate real oviraptor eggs as best as we could.”

When the team ran experiments to find out if clutch attendance of a brooding adult or different environmental circumstances may have impacted hatching patterns, they found that in colder temperatures, where a brooding adult attended the clutch, the eggs’ temperatures in the outer ring differed by up to 6°C, which could have resulted in asynchronous hatching, a pattern where eggs in the same nest hatch at different times. In warmer conditions, the difference in egg temperatures in the outer ring was just 0.6°C, suggesting that oviraptors living in warmer conditions may have exhibited a different pattern of asynchronous hatching because they could use the sun as an additional, powerful heat source.

“It’s unlikely that large dinosaurs sat atop their clutches. Supposedly they used the heat of the sun or soil to hatch their eggs, like turtles. Since oviraptor clutches are open to the air, heat from the sun likely mattered much more than heat from the soil,” Yang explained.

Better hatchers?

The team also investigated how oviraptor incubation efficiency compares to that of modern birds. Most birds use thermoregulatory contact incubation (TCI), where adults sit directly on the eggs to transfer heat. TCI requires three prerequisites – the adult bird must be in contact with every egg, be the main heat source, and maintain all eggs within a constrained temperature range – which oviraptors didn’t fulfil. For example, their egg arrangement prevented the adult from making full contact with all eggs in the clutch.

“Oviraptors may not have been able to conduct TCI as modern birds do,” said Su. Instead, these dinosaurs and the sun may have been co-incubators – a less efficient incubation behavior than that displayed by modern birds. Yet, the combination of adult incubation and an ambient heat source – perhaps a behavioral adaptation associated with the evolution from buried to semi-open nests – isn’t necessarily worse.

“Modern birds aren’t ‘better’ at hatching eggs. Instead, birds living today and oviraptors have a very different way of incubation or, more specifically, brooding,” Yang pointed out. “Nothing is better or worse. It just depends on the environment.”

The team pointed out that their findings are specific to the reconstructed nest and are limited by the fact that today’s climate does not resemble the Late Cretaceous climate, which may have impacted the results. Oviraptors also exhibited a longer incubation period than modern birds.

Yet, the study advances our understanding of oviraptor brooding strategies through innovative approaches. It represents an important bridge between physics-based simulations and paleontological interpretations, potentially enabling paleontologists to investigate topics for which approaches were limited until now.  

“It also truly is an encouragement for all students, especially in Taiwan,” concluded Yang. “There are no dinosaur fossils in Taiwan but that does not mean that we cannot do dinosaur studies.”

Lateral view of the clutch with the incubator on top

Photograph of the generalized clutch after Experiment III.

Dorsal view of the incubator.

Credit

Chun-Yu Su.

The arrangement of thermometers in the incubation experiments. Thermometers 1 (with thicker outlines) were used in Experiment II. Thermometers 2 (with lighter outlines) were the additional thermometers used in Experiment III. The schematic presents a lateral view of the clutch and the incubator.

Credit

Su et al.,2026.

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Journal

Frontiers in Ecology and Evolution

DOI

10.3389/fevo.2026.1351288 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Heat transfer in a realistic clutch reveals a lower efficiency in incubation of oviraptorid dinosaurs than of modern birds

Article Publication Date

17-Mar-2026