Ectothermy

@misc{bakker1975dinosaur1,
    author = "Bakker, R. T",
    title = "Dinosaur Renaissance",
    year = "1975",
    howpublished = "Scientific American, v. 232, p. 58- 78",
    note = "talkorigins\_source = {true}; raw\_reference = {Bakker, R. T., 1975, Dinosaur Renaissance: Scientific American, v. 232, p. 58- 78.}"
}

@article{doi101038scientificamerican047558,
    author = "Bakker, Robert T.",
    title = "Dinosaur Renaissance",
    year = "1975",
    journal = "Scientific American",
    url = "https://doi.org/10.1038/scientificamerican0475-58",
    doi = "10.1038/scientificamerican0475-58",
    openalex = "W4236582943"
}

@article{bentley1978the,
    author = "Bentley, Barbara L.",
    title = "The Warm-Blooded Dinosaurs. Julian May",
    year = "1978",
    journal = "The Quarterly Review of Biology",
    url = "https://doi.org/10.1086/410811",
    doi = "10.1086/410811",
    number = "4",
    openalex = "W2508933159",
    pages = "430-430",
    volume = "53"
}

@misc{marx1978warmblooded2,
    author = "Marx, J. L",
    title = "Warm-blooded dinosaurs",
    year = "1978",
    howpublished = "Evidence pro and con: Science, v. 199, p. 1424-1426",
    note = "talkorigins\_source = {true}; raw\_reference = {Marx, J. L., 1978, Warm-blooded dinosaurs: Evidence pro and con: Science, v. 199, p. 1424-1426.}"
}

The ratio of carnivorous to herbivorous dinosaur skeletons from Dinosaur Provincial Park has been cited as evidence of endothermy in dinosaurs. In living populations of large endothermic mammals, carnivore biomass represents approximately 1% of total biomass. Two models describing energy flow from herbivores to carnivores indicate that tyrannosaurids are three to four times more abundant in the fossil sample than would have been the case if they were endothermic. Either the fossil sample does not adequately reflect relative abundances of large dinosaurs in the ancient community, or large dinosaurs were ectothermic.

@article{béland1979ectothermy,
    author = "Béland, P. and Russell, D. A.",
    title = "Ectothermy in dinosaurs: paleoecological evidence from Dinosaur Provincial Park, Alberta",
    year = "1979",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "The ratio of carnivorous to herbivorous dinosaur skeletons from Dinosaur Provincial Park has been cited as evidence of endothermy in dinosaurs. In living populations of large endothermic mammals, carnivore biomass represents approximately 1\% of total biomass. Two models describing energy flow from herbivores to carnivores indicate that tyrannosaurids are three to four times more abundant in the fossil sample than would have been the case if they were endothermic. Either the fossil sample does not adequately reflect relative abundances of large dinosaurs in the ancient community, or large dinosaurs were ectothermic.",
    url = "https://doi.org/10.1139/e79-024",
    doi = "10.1139/e79-024",
    number = "2",
    pages = "250-255",
    volume = "16"
}

A physical, model-based approach to body temperatures in dinosaurs allows us to predict what ranges of body temperatures and what thermoregulatory strategies were available to those dinosaurs. We argue that 1. The huge range of body sizes in the dinosaurs likely resulted in very different thermal problems and strategies for animals at either end of this size continuum. 2. Body temperatures of the smallest adult dinosaurs and of hatchlings and small juveniles would have been largely insensitive to metabolic rates in the absence of insulation. The smallest animals in which metabolic heating resulted in predicted body temperatures ≥ 2°C above operative temperatures (T e) weigh 10 kg. Body temperature would respond rapidly enough to changes in T e to make behavioral thermoregulation possible. 3. Body temperatures of large dinosaurs (>1000 kg) likely were sensitive to both metabolic rate and the delivery of heat to the body surface by blood flow. Our model suggests that they could adjust body temperature by adjusting metabolic rate and blood flow. Behavioral thermoregulation by changing microhabitat selection would likely have been of limited utility because body temperatures would have responded only slowly to changes in T e. 4. Endothermic metabolic rates may have put large dinosaurs at risk for overheating unless they had adaptations to shed the heat as necessary. This would have been particularly true for dinosaurs with masses > 10,000 kg, but simulations suggest that for animals as small as 1000 kg in the Tropics and in temperate latitudes during the summer, steady-state body temperatures would have exceeded 40°C. Slow response of body temperatures to changes in T e suggests that use of day-night thermal differences would have buffered dinosaurs from diel warming but would not have lowered body temperatures sufficiently for animals experiencing high mean daily T e. 5. Endothermic metabolism and metabolic heating might have been useful for intermediate and large-sized (100–3000 kg) dinosaurs but often in situations that demanded marked seasonal adjustment of metabolic rates and/or precise control of metabolism (and heat-loss mechanisms) as typically seen in endotherms.

@article{doi101017s0094837300021321,
    author = "O′Connor, Michael and Dodson, Peter",
    title = "Biophysical constraints on the thermal ecology of dinosaurs",
    year = "1999",
    journal = "Paleobiology",
    abstract = "A physical, model-based approach to body temperatures in dinosaurs allows us to predict what ranges of body temperatures and what thermoregulatory strategies were available to those dinosaurs. We argue that 1. The huge range of body sizes in the dinosaurs likely resulted in very different thermal problems and strategies for animals at either end of this size continuum. 2. Body temperatures of the smallest adult dinosaurs and of hatchlings and small juveniles would have been largely insensitive to metabolic rates in the absence of insulation. The smallest animals in which metabolic heating resulted in predicted body temperatures ≥ 2°C above operative temperatures (T e) weigh 10 kg. Body temperature would respond rapidly enough to changes in T e to make behavioral thermoregulation possible. 3. Body temperatures of large dinosaurs (>1000 kg) likely were sensitive to both metabolic rate and the delivery of heat to the body surface by blood flow. Our model suggests that they could adjust body temperature by adjusting metabolic rate and blood flow. Behavioral thermoregulation by changing microhabitat selection would likely have been of limited utility because body temperatures would have responded only slowly to changes in T e. 4. Endothermic metabolic rates may have put large dinosaurs at risk for overheating unless they had adaptations to shed the heat as necessary. This would have been particularly true for dinosaurs with masses > 10,000 kg, but simulations suggest that for animals as small as 1000 kg in the Tropics and in temperate latitudes during the summer, steady-state body temperatures would have exceeded 40°C. Slow response of body temperatures to changes in T e suggests that use of day-night thermal differences would have buffered dinosaurs from diel warming but would not have lowered body temperatures sufficiently for animals experiencing high mean daily T e. 5. Endothermic metabolism and metabolic heating might have been useful for intermediate and large-sized (100–3000 kg) dinosaurs but often in situations that demanded marked seasonal adjustment of metabolic rates and/or precise control of metabolism (and heat-loss mechanisms) as typically seen in endotherms.",
    url = "https://doi.org/10.1017/s0094837300021321",
    doi = "10.1017/s0094837300021321",
    openalex = "W2264731691",
    references = "crossref1998encyclopedia, doi1010079781461260240, doi101007bf00024969, doi101017s0022336000036076, doi10106313128494, doi1023071942620, doi1023071948545, doi1023072258713, openalexw1558456135, openalexw3215057009, openalexw656806957"
}

Despite numerous studies, the thermal physiology of dinosaurs remains unresolved. Thus, perhaps the commonly asked question whether dinosaurs were ectotherms or endotherms is inappropriate, and it is more constructive to ask which dinosaurs were likely to have been endothermic and which ones ectothermic. Field data from crocodiles over a large size range show that body temperature fluctuations decrease with increasing body mass, and that average daily body temperatures increase with increasing mass. A biophysical model, the biological relevance of which was tested against field data, was used to predict body temperatures of dinosaurs. However, rather than predicting thermal relations of a hypothetical dinosaur, the model considered correct paleogeographical distribution and climate to predict the thermal relations of a large number of dinosaurs known from the fossil record (>700). Many dinosaurs could have had “high” (>30°) and stable (daily amplitude >2°) body temperatures without metabolic heat production even in winter, so it is unlikely that selection pressure would have favored the evolution of elevated resting metabolic rates in those species. Recent evidence of ontogenetic growth rates indicates that even the juveniles of large species (3000–4000 kg) could have had biologically functional body temperature ranges during early development. Smaller dinosaurs (45°) could not have had high and stable body temperatures without metabolic heat production. However, elevated metabolic rates were unlikely to have provided selective advantage in the absence of some form of insulation, so probably insulation was present before endothermy evolved, or else it coevolved with elevated metabolic rates. Superimposing these findings onto a phylogeny of the Dinosauria suggests that endothermy most likely evolved among the Coelurosauria and, to a lesser extent, among the Hypsilophodontidae, but not among the Stegosauridae, Nodosauridae, Ankylosauridae, Hadrosauridae, Ceratopsidae, Prosauropoda, and Sauropoda.

@article{doi1016660094837320030290105dbttoo20co2,
    author = "Seebacher, Frank",
    title = "Dinosaur body temperatures: the occurrence of endothermy and ectothermy",
    year = "2003",
    journal = "Paleobiology",
    abstract = "Despite numerous studies, the thermal physiology of dinosaurs remains unresolved. Thus, perhaps the commonly asked question whether dinosaurs were ectotherms or endotherms is inappropriate, and it is more constructive to ask which dinosaurs were likely to have been endothermic and which ones ectothermic. Field data from crocodiles over a large size range show that body temperature fluctuations decrease with increasing body mass, and that average daily body temperatures increase with increasing mass. A biophysical model, the biological relevance of which was tested against field data, was used to predict body temperatures of dinosaurs. However, rather than predicting thermal relations of a hypothetical dinosaur, the model considered correct paleogeographical distribution and climate to predict the thermal relations of a large number of dinosaurs known from the fossil record (>700). Many dinosaurs could have had “high” (>30°) and stable (daily amplitude >2°) body temperatures without metabolic heat production even in winter, so it is unlikely that selection pressure would have favored the evolution of elevated resting metabolic rates in those species. Recent evidence of ontogenetic growth rates indicates that even the juveniles of large species (3000–4000 kg) could have had biologically functional body temperature ranges during early development. Smaller dinosaurs (45°) could not have had high and stable body temperatures without metabolic heat production. However, elevated metabolic rates were unlikely to have provided selective advantage in the absence of some form of insulation, so probably insulation was present before endothermy evolved, or else it coevolved with elevated metabolic rates. Superimposing these findings onto a phylogeny of the Dinosauria suggests that endothermy most likely evolved among the Coelurosauria and, to a lesser extent, among the Hypsilophodontidae, but not among the Stegosauridae, Nodosauridae, Ankylosauridae, Hadrosauridae, Ceratopsidae, Prosauropoda, and Sauropoda.",
    url = "https://doi.org/10.1666/0094-8373(2003)029<0105:dbttoo>2.0.co;2",
    doi = "10.1666/0094-8373(2003)029<0105:dbttoo>2.0.co;2",
    openalex = "W2175225824",
    references = "doi101016s016953470102198x, doi101017s0094837300021321, doi101038scientificamerican126292, doi101086283547, doi101086648217, doi101126science28454232137, doi101126science493968, doi101306c1ea47bb16c911d78645000102c1865d, doi105860choice331556, openalexw2002729176, openalexw3149443718, zhao1998the"
}

@misc{hillenius2006dinosaur,
    author = "Hillenius, Willem J",
    title = "Dinosaur Physiology: Were Dinosaurs Warm‐blooded?",
    year = "2006",
    booktitle = "Encyclopedia of Life Sciences",
    url = "https://doi.org/10.1038/npg.els.0003323",
    doi = "10.1038/npg.els.0003323"
}

@article{crossref2009were,
    title = "Were dinosaurs warm-blooded and nimble?",
    year = "2009",
    journal = "Physics Today",
    url = "https://doi.org/10.1063/pt.5.023835",
    doi = "10.1063/pt.5.023835",
    number = "11",
    openalex = "W4250202419",
    volume = "2009"
}

To evaluate the possible physiology of dinosaurs, comparisons must be made with their closest living relatives: birds and crocodilians. Although crocodilians maintain ectothermic metabolic rates and have anatomy reflective of this, modern birds achieve high, endothermic metabolic rates through specialised soft tissues supported by unique skeletal attributes. Finding similar shared characters in dinosaurs that are functionally linked to metabolic rates in birds or crocodilians allows plausible reconstruction of dinosaur physiology. Examinations of dinosaur remains reveal no structures with clear functional association with bird‐like respiratory or metabolic physiology, and in some cases indicate crocodilian‐like anatomy. Consequently, dinosaurs were most likely ectothermic, with resting and maximal metabolic rates that were lower than those of modern mammals or birds. However, given the favourable Mesozoic climatic conditions, most dinosaurs were probably able to maintain high, constant body temperatures through behavioural or inertial thermoregulation. Key Concepts: Reconstructing the biology of extinct forms relies on comparison with living taxa that share the same specialised features linked to specific function. Stable body temperature can be achieved through behavioural mechanisms or through virtue of large mass, and need not rely on a particular metabolic strategy. The closest living relatives of dinosaurs are birds and crocodilians, which have widely different metabolic rates supported by different respiratory and skeletal anatomy. Some dinosaur remains preserve evidence, such as postcranial pneumaticity, that may be superficially suggestive of modern bird‐like respiratory anatomy, but they lack other features critical for the ability to ventilate bird‐like lungs or achieve bird‐like aerobic capacity. No dinosaur remains show evidence of respiratory turbinates, a skeletal character functionally associated with modern endothermy. Endothermy was not likely achieved in dinosaurs, but was first present in mid‐Cretaceous birds. Some dinosaurs may have increased aerobic capacity using a crocodilian‐like ventilatory mechanism.

@misc{quick2013dinosaur,
    author = "Quick, Devon E and Hillenius, Willem J",
    title = "Dinosaur Physiology: Were Dinosaurs Warm‐Blooded?",
    year = "2013",
    booktitle = "Encyclopedia of Life Sciences",
    abstract = "To evaluate the possible physiology of dinosaurs, comparisons must be made with their closest living relatives: birds and crocodilians. Although crocodilians maintain ectothermic metabolic rates and have anatomy reflective of this, modern birds achieve high, endothermic metabolic rates through specialised soft tissues supported by unique skeletal attributes. Finding similar shared characters in dinosaurs that are functionally linked to metabolic rates in birds or crocodilians allows plausible reconstruction of dinosaur physiology. Examinations of dinosaur remains reveal no structures with clear functional association with bird‐like respiratory or metabolic physiology, and in some cases indicate crocodilian‐like anatomy. Consequently, dinosaurs were most likely ectothermic, with resting and maximal metabolic rates that were lower than those of modern mammals or birds. However, given the favourable Mesozoic climatic conditions, most dinosaurs were probably able to maintain high, constant body temperatures through behavioural or inertial thermoregulation. Key Concepts: Reconstructing the biology of extinct forms relies on comparison with living taxa that share the same specialised features linked to specific function. Stable body temperature can be achieved through behavioural mechanisms or through virtue of large mass, and need not rely on a particular metabolic strategy. The closest living relatives of dinosaurs are birds and crocodilians, which have widely different metabolic rates supported by different respiratory and skeletal anatomy. Some dinosaur remains preserve evidence, such as postcranial pneumaticity, that may be superficially suggestive of modern bird‐like respiratory anatomy, but they lack other features critical for the ability to ventilate bird‐like lungs or achieve bird‐like aerobic capacity. No dinosaur remains show evidence of respiratory turbinates, a skeletal character functionally associated with modern endothermy. Endothermy was not likely achieved in dinosaurs, but was first present in mid‐Cretaceous birds. Some dinosaurs may have increased aerobic capacity using a crocodilian‐like ventilatory mechanism.",
    url = "https://doi.org/10.1002/9780470015902.a0003323.pub2",
    doi = "10.1002/9780470015902.a0003323.pub2"
}

The non-marine Horseshoe Canyon Formation (HCFm, southern Alberta) yields taxonomically diverse, late Campanian to middle Maastrichtian dinosaur assemblages that play a central role in documenting dinosaur evolution, paleoecology, and paleobiogeography leading up to the end-Cretaceous extinction. Here, we present high-precision U–Pb CA–ID–TIMS ages and the first calibrated chronostratigraphy for the HCFm using zircon grains from (1) four HCFm bentonites distributed through 129 m of section, (2) one bentonite from the underlying Bearpaw Formation, and (3) a bentonite from the overlying Battle Formation that we dated previously. In its type area, the HCFm ranges in age from 73.1–68.0 Ma. Significant paleoenvironmental and climatic changes are recorded in the formation, including (1) a transition from a warm-and-wet deltaic setting to a cooler, seasonally wet-dry coastal plain at 71.5 Ma, (2) maximum transgression of the Drumheller Marine Tongue at 70.896 ± 0.048 Ma, and (3) transition to a warm-wet alluvial plain at 69.6 Ma. The HCFm’s three mega-herbivore dinosaur assemblage zones track these changes and are calibrated as follows: Edmontosaurus regalis – Pachyrhinosaurus canadensis zone, 73.1–71.5 Ma; Hypacrosaurus altispinus – Saurolophus osborni zone, 71.5–69.6 Ma; and Eotriceratops xerinsularis zone, 69.6–68.2 Ma. The Albertosaurus Bonebed — a monodominant assemblage of tyrannosaurids in the Tolman Member — is assessed an age of 70.1 Ma. The unusual triceratopsin, Eotriceratops xerinsularis, from the Carbon Member, is assessed an age of 68.8 Ma. This chronostratigraphy is useful for refining correlations with dinosaur-bearing upper Campanian–middle Maastrichtian units in Alberta and elsewhere in North America.

@article{doi101139cjes20190019,
    author = "Eberth, David A. and Kamo, Sandra L.",
    title = "High-precision U–Pb CA–ID–TIMS dating and chronostratigraphy of the dinosaur-rich Horseshoe Canyon Formation (Upper Cretaceous, Campanian–Maastrichtian), Red Deer River valley, Alberta, Canada",
    year = "2019",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "The non-marine Horseshoe Canyon Formation (HCFm, southern Alberta) yields taxonomically diverse, late Campanian to middle Maastrichtian dinosaur assemblages that play a central role in documenting dinosaur evolution, paleoecology, and paleobiogeography leading up to the end-Cretaceous extinction. Here, we present high-precision U–Pb CA–ID–TIMS ages and the first calibrated chronostratigraphy for the HCFm using zircon grains from (1) four HCFm bentonites distributed through 129 m of section, (2) one bentonite from the underlying Bearpaw Formation, and (3) a bentonite from the overlying Battle Formation that we dated previously. In its type area, the HCFm ranges in age from 73.1–68.0 Ma. Significant paleoenvironmental and climatic changes are recorded in the formation, including (1) a transition from a warm-and-wet deltaic setting to a cooler, seasonally wet-dry coastal plain at 71.5 Ma, (2) maximum transgression of the Drumheller Marine Tongue at 70.896 ± 0.048 Ma, and (3) transition to a warm-wet alluvial plain at 69.6 Ma. The HCFm’s three mega-herbivore dinosaur assemblage zones track these changes and are calibrated as follows: Edmontosaurus regalis – Pachyrhinosaurus canadensis zone, 73.1–71.5 Ma; Hypacrosaurus altispinus – Saurolophus osborni zone, 71.5–69.6 Ma; and Eotriceratops xerinsularis zone, 69.6–68.2 Ma. The Albertosaurus Bonebed — a monodominant assemblage of tyrannosaurids in the Tolman Member — is assessed an age of 70.1 Ma. The unusual triceratopsin, Eotriceratops xerinsularis, from the Carbon Member, is assessed an age of 68.8 Ma. This chronostratigraphy is useful for refining correlations with dinosaur-bearing upper Campanian–middle Maastrichtian units in Alberta and elsewhere in North America.",
    url = "https://doi.org/10.1139/cjes-2019-0019",
    doi = "10.1139/cjes-2019-0019",
    openalex = "W2979872101",
    references = "andeberth2016new, doi101007springerreference4923, doi1010160016703773902135, doi101016jchemgeo200503011, doi101016jgca200509007, doi101016jgca201006017, doi101016s0009254196000332, doi101016s0195667105800308, doi101073pnas1313334111, doi101103physrevc41889, doi101126science1154339, doi101126science1230492, doi101139cjes20120185, doi101371journalpone0188426, doi104202app20110033, doi105860choice435902, openalexw2989049194"
}

Most Notosuchia were active terrestrial predators. A few were semi-aquatic, or were insectivorous, omnivorous or herbivorous. A question relative to their thermometabolism remains to be answered: were Notosuchia warm-blooded? Here we use quantitative bone palaeohistology to answer this question. Two variables were used as proxies to infer thermometabolism: resting metabolic rate and red blood cell dimensions. Resting metabolic rate was inferred using relative primary osteon area and osteocyte size, shape and density. Blood cell dimensions were inferred using harmonic mean canal diameter and minimum canal diameter. All inferences were performed using phylogenetic eigenvector maps. Both sets of analyses suggest that the seven species of Notosuchia sampled in this study were ectotherms. Given that extant Neosuchia (their sister group) are also ectotherms, and that archosaurs were primitively endotherms, parsimony suggests that endothermy may have been lost at the node Metasuchia (Notosuchia–Neosuchia) by the Early Jurassic. Semi-aquatic taxa such as Pepesuchus may have had thermoregulatory strategies similar to those of recent crocodylians, whereas the terrestrial taxa (Araripesuchus, Armadillosuchus, Iberosuchus, Mariliasuchus, Stratiotosuchus) may have been thermoregulators similar to active predatory varanids. Thermal inertia may have contributed to maintaining a stable temperature in large notosuchians such as Baurusuchus.

@article{cubo2020were,
    author = "Cubo, Jorge and Sena, Mariana V A and Aubier, Paul and Houee, Guillaume and Claisse, Penelope and Faure-Brac, Mathieu G and Allain, Ronan and Andrade, Rafael C L P and Sayão, Juliana M and Oliveira, Gustavo R",
    title = "Were Notosuchia (Pseudosuchia: Crocodylomorpha) warm-blooded? A palaeohistological analysis suggests ectothermy",
    year = "2020",
    journal = "Biological Journal of the Linnean Society",
    abstract = "Most Notosuchia were active terrestrial predators. A few were semi-aquatic, or were insectivorous, omnivorous or herbivorous. A question relative to their thermometabolism remains to be answered: were Notosuchia warm-blooded? Here we use quantitative bone palaeohistology to answer this question. Two variables were used as proxies to infer thermometabolism: resting metabolic rate and red blood cell dimensions. Resting metabolic rate was inferred using relative primary osteon area and osteocyte size, shape and density. Blood cell dimensions were inferred using harmonic mean canal diameter and minimum canal diameter. All inferences were performed using phylogenetic eigenvector maps. Both sets of analyses suggest that the seven species of Notosuchia sampled in this study were ectotherms. Given that extant Neosuchia (their sister group) are also ectotherms, and that archosaurs were primitively endotherms, parsimony suggests that endothermy may have been lost at the node Metasuchia (Notosuchia–Neosuchia) by the Early Jurassic. Semi-aquatic taxa such as Pepesuchus may have had thermoregulatory strategies similar to those of recent crocodylians, whereas the terrestrial taxa (Araripesuchus, Armadillosuchus, Iberosuchus, Mariliasuchus, Stratiotosuchus) may have been thermoregulators similar to active predatory varanids. Thermal inertia may have contributed to maintaining a stable temperature in large notosuchians such as Baurusuchus.",
    url = "https://doi.org/10.1093/biolinnean/blaa081",
    doi = "10.1093/biolinnean/blaa081",
    number = "1",
    openalex = "W3043134336",
    pages = "154-162",
    volume = "131",
    references = "doi101016s1342937x05710790, doi1010719781486300679, doi101086283547, doi101086422766, doi101093biolinneanblw044, doi101093icb392189, doi101098rsbl20050378, doi101111j1469185x201000122x, doi101126science1180219, doi101371journalpone0093105, doi103897zookeys28325"
}

@misc{crossref2022were,
    title = "Were dinosaurs warm blooded? New study says yes",
    year = "2022",
    booktitle = "AAAS Articles DO Group",
    url = "https://doi.org/10.1126/science.add2036",
    doi = "10.1126/science.add2036",
    openalex = "W4281568779"
}

Dinosaurs have attracted varying degrees of scientific and public interest since their initial description in 1824. Interest has steadily increased, however, since the late 1960s when the Dinosaur Renaissance began, and when the Canadian Journal of Earth Sciences started to publish. Since then, there has been a feedback system (international in scope) promoting increased scientific activity and ever-increasing public attention. This has led to ever more dinosaur discoveries internationally; increased numbers of museums and parks displaying dinosaurs; more publications, blogs, and other media on dinosaurs; and (most importantly) increased numbers of people and institutions doing research on dinosaurs. About 30 new species of dinosaurs are now being described every year, adding to the more than 1000 species already known. Furthermore, it is now acknowledged by most biologists and palaeontologists that modern birds are the direct descendants of dinosaurs, and that they are classified as part of the Dinosauria. Recognizing that there are more than 11 000 species of living dinosaurs has given us a better understanding of many aspects of the biology of nonavian dinosaurs. Along with technological improvements, this has revealed new—and often surprising—facts about their anatomy (bones, soft tissues, and even colours), interrelationships, biomechanics, growth and variation, ecology, physiology, behaviour, and extinction. In spite of the intensity of research over the last six decades, there is no indication that the discovery of new species and new facts about their biology is slowing down. It is quite clear that there is still a lot to be learned!

@article{doi101139cjes20220131,
    author = "Currie, Philip J.",
    title = "Celebrating dinosaurs: their behaviour, evolution, growth, and physiology",
    year = "2023",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "Dinosaurs have attracted varying degrees of scientific and public interest since their initial description in 1824. Interest has steadily increased, however, since the late 1960s when the Dinosaur Renaissance began, and when the Canadian Journal of Earth Sciences started to publish. Since then, there has been a feedback system (international in scope) promoting increased scientific activity and ever-increasing public attention. This has led to ever more dinosaur discoveries internationally; increased numbers of museums and parks displaying dinosaurs; more publications, blogs, and other media on dinosaurs; and (most importantly) increased numbers of people and institutions doing research on dinosaurs. About 30 new species of dinosaurs are now being described every year, adding to the more than 1000 species already known. Furthermore, it is now acknowledged by most biologists and palaeontologists that modern birds are the direct descendants of dinosaurs, and that they are classified as part of the Dinosauria. Recognizing that there are more than 11 000 species of living dinosaurs has given us a better understanding of many aspects of the biology of nonavian dinosaurs. Along with technological improvements, this has revealed new—and often surprising—facts about their anatomy (bones, soft tissues, and even colours), interrelationships, biomechanics, growth and variation, ecology, physiology, behaviour, and extinction. In spite of the intensity of research over the last six decades, there is no indication that the discovery of new species and new facts about their biology is slowing down. It is quite clear that there is still a lot to be learned!",
    url = "https://doi.org/10.1139/cjes-2022-0131",
    doi = "10.1139/cjes-2022-0131",
    openalex = "W4321453118",
    references = "crossref1998encyclopedia, doi101017s247526300000091x, doi101038001189d0, doi101038137179b0, doi10103831635, doi10103834356, doi105860choice326223, doi105860choice435902, openalexw1535663436, openalexw2527820321"
}