Monday, December 18, 2017

On the Behavior and Care of Dinosaurs in Captivity

Has anyone seen the Jurassic Park and Jurassic World movies?

If so, have you ever wondered what it would be like to keep these dinosaurs (minus getting eaten, of course)?

In our childhoods, we've often dreamt of how cool it would be to own a living, breathing dinosaur (that is not a bird).  It's much like we would dream of owning our first pet, whether it was a cat, a dog, or even a lizard.  But by the time we actually do get the pet, we were both told and find that it takes a lot of responsibility and special treatment to take of care of our pets.

The same would be said for IF dinosaurs were ever brought back from extinction.

Here, I will use nine of some of the most popular and well-known dinosaurs, look up any kind of information about them (along with their relatives to help expand the image), look up living modern animals that could or do show similar behaviors or physiological circumstances, and list them down as possible welfare concerns.  Along with that, I will also conclude with a list of welfare concerns that would to be considered for all dinosaur species, a list of general welfare concerns.

So, continue and enjoy.

PS:  This article will be updated when I find new information or new discoveries in paleontology are made, so keep sharp.  If you have theories, post them on the comment section below and if I find them plausible, I shall post them and give you credit.

Keys to Animal Welfare

Before we start, I would like to give you some ideas or refreshers on animal welfare is measured or judged.  In the UK, they use an outline of aspects that are called the Five Freedoms to evaluate the welfare of animals in a particular facility.  Those Five Freedoms are:

  • Freedom from hunger or thirst
    • Basically to have access to fresh water and an adequate healthy diet
  • Freedom from discomfort
    • Providing an environment with shade and comfort 
  • Freedom from pain, injury, or disease
    • Prevention or rapid diagnosis and treatment
  • Freedom to express natural behavior
    • Being given plenty of space, facilities, enrichment, and company to avoid abnormal behaviors
  • Freedom from fear and distress
    • Making certain that living conditions and style are mentally healthy.

When determining an animal's welfare, it's good to keep these freedoms in mind and the more you know about the animal's basic biology and needs, you can be able to provide the said animal the best general welfare you can provide it.

With these in mind, let's see what kind of welfare concerns would our dinosaurs have.


-It might be wise to investigate the calcium and phosphorus requirements (along with Vitamin D) of the Stegosaurus, most likely to help out with the shape and health of it's iconic back plates.

-With the dangers of the Stegosaur's plates and thagomizers getting caught or damaged in a confined environment, it is wise to keep them in a open environment.  If confinement is needed, considerations will be needed in designing holding facilities or restraining technologies to work with the dinosaur's physiology for it's protection.  But it maybe wise to need a wary eye so that they don't wear down their beak too much in boredom.

-The Stegosaur's small head would possibly be of concern, especially since it could get into small spaces that it would potentially get stuck to and accidentally pull it's own head off in panic.

-Due to it's supposed environment is dry (like the african savanna), humidity is a consideration.

-A stegosaur's walking gait is more akin to that an elephant (also known as graviportal) and could stand on a bipedal stance, with the tail acting like a third leg.  However, this behavior is most likely uncommon (much like how a bipedal stance is for wild elephants).


( An Out-Dated illustration of Triceratops

-Due to it's large brow horns and neck frill, designs on the alleys, pens, cages, barns, and other holding/handling facilities should consider on this.

-With the frill, it may need to be noted that a proper calcium:phosphorus ratio and the proper supplements for said minerals would be needed.  Calcium deficiency would evidenced by deformed abnormalities with the frill as the Triceratops grows into adulthood.

-Much like giraffes, horses, and other large terrestrial herbivores, Triceratops most likely spend the majority of it's time feasting.  Due to being adapted to browse constantly, it would most likely develop orally-related stereotypical behavior (much like 'cribbing' is in horses).

-With the stereotypical behavior mentioned above, it would be wise to actually not contain a Triceratops behind electric wire in a enclosed area.  Reason being that in black rhinos, they are known to mouth onto wire when they are bored or curious and when they mouth the electric wire, the electric current would make the animal not let go of the wire and will die if left alone.  With this in mind, heavy duty bars or/and concrete walls are preferable to use in containment.

-Much like with rhinos and elephants, proper foot care would be needed (though it's feet seem to be more similar to that of hippos).

Triceratops Foot

-Condition of the beak would definitely need to watch out for.  If it's like a bird, it would need large boulder or a large structure covered with a sandpaper-like material so they can wear it down to prevent overgrowth (may need to watch out for it though, for it may use rub them against their bodies to take care of dry skin or skin parasites).  Failure to do so would perhaps require beak trimming from a veterinarian.  Research on this would be needed.

-Much like elephants and rhinos of today, dust and mud baths are perhaps essential for the removal of skin parasites and to cool off from the heat (in the case of the mud baths).

-Compared to some other ceratopsians, such as Styracosaurus, Triceratops were more physical in their fights and displays.  Caution on aggressive behavior is needed, along with fights.

-If the frills are used as a sort of intra-species identification, they might be colorful and would indicate that Triceratops can see in color or more shades of color previously thought.  Using color as enrichment could perhaps be a possibility.

-Recent evidence has shown that the triceratops had a thick keratin skin covering across it's frill, eye-brow horns, and nasal horn.  Using mineral oil on it in check and dietary requirements would need to be considered it to look healthy and tended to (But don't let the mineral oil get into the animal's eyes).

An illustration of a Triceratops with keratin-covered face (Illustrated and Permission by Jason Abdale)

-(Personal Hypothesis) With the possibility of the color pattern of the frill being important for intra-specific interactions, it is possible that the infant triceratops would need to recognize the unique pattern of their mother's frill colors to know who is who, much like zebra foal with their mother's stripes.  In this stage, the mother would be pushy and will fiercely deter any other individual triceratops at that moment after the eggs have hatched.

-Considering their teeth structure, possible feeding behavior, and diet, the probable diet for captive Triceratops would be as follows:
  • Alfalfa Hay - Common foodstuffs for browsing species, mid grade cuttings would be most preferable (enough leaves to provide nutrition and enough stems to provide roughage).  Has protein and calcium levels that would be much needed.
  • Moose Feed - Due to their teeth's design to chew on extremely fibrous vegetation, moose feed would be needed (due to it being 22.5% saw dust of aspen).
  • Browse - Basically branches and leaves from non-toxic trees (e.g., palm tree leaves).
  • Sodium - Like all large herbivores, triceratops would need sodium (salt) to supplement their diet.
-Along for digestive system-related reasons, moose feed and browse (both of which are highly fibrous) would also help the Triceratops' dentition.  The dinosaur's back teeth are self-replacing and operate like scissors, as opposed to mammalian ungulate back teeth that are continuously growing and flat grinding.  Due to that, Triceratops jaws are adapted to orally process highly fibrous foodstuffs.  Failing to provide 'hardy food' and only providing 'soft food' would cause dentition issues that would compromise chewing food (similar to how captive elephants suffer similar issues).

-When transporting the Triceratops, the horns must watched out for. This is because that the horns could get caught into holes or other snags in the transport and would break their horns, which would led to infection. Protection for their horns shoul be done for both animal and human safety.
My childish illustration of what to put on Triceratops horns during transport.

-Smaller species of ceratopsians have been documented to be discovered in burrows.  Whether the ceratopsians made the burrows themselves or simply live in abandoned burrows of other species is unknown, it might need to be worth noting that ceratopsians might be capable to digging.  While it might be unlikely triceratops would burrow, it should be worth noting for containment and paddock maintenance concerns.  It might also be noted that the triceratops might dig up holes to make wallows (somewhat similar to rhino mud wallows) and maybe even dig for water in the dry season.


-Due to bony armor, demand for calcium in the diet is most likely high.  To not do so would undoubtedly encourage the developed of weak bone, distorted armor, and other calcium deficiency issues.

-For ankylosaurs and other related species that come from moist environments, mineral oil-based ointments should perhaps be used on their shells to help out with shell appearance and health.

-Examinations of the skull indicates that the Ankylosaurus has a long tongue, like either a cow or a giraffe.  With this in mind, it is possible to model feeders and such devices in a style similar to that for cattle and giraffes.  It is also possible to use the same kind of salt licks used for cattle on Ankylosaurus.


-Due to the ankylosaur's clubbed tail and the danger it would pose to people, facilities, and even itself, considerations on this MUST be made when designing the enclosure and other facilities for the said dinosaur.  Fences and walls would need to be lined with devices to buffer the impact of a swinging clubbed tail (large rubber-lined shock absorbers or tractor tires could be considered).

-Due to the humid environment of the ankylosaur's habitat, humidity levels indoors must be determined to avoid sinus conditions.  And since the said species has huge nasal chambers, it's most certainly a must.

-Due to it's retracted nostrils (similar to that of some digging reptiles), it's possible that the ankylosaur did some earth-moving behavior, to search for roots and tubers like modern pigs do today.  For enrichment purposes, a wide (twice as wide and long) and deep (half the height) sandbox would be good, along with hiding tuberous food (e.g. carrots, potatoes, turnips, etc.) would be grand.  But for containment and security purposes, anti-digging applications on fences (underground bars, cement walls, etc.) will be needed.

Tyrannosaurus rex
*Some of the possible welfare concerns of keeping Tyrannnosaurus rex in captivity have been talked about and listed in another one of my blog articles: Welfare Review of Jurassic World's Tyrannosaurus Rex Part1, but I will list down them and other previously unmentioned welfare concerns below*

-Taking both the consideration of both the tyrannosaur's size and the possibly of it having the same roaming behavior as modern large predators, a paddock the size of a football would perhaps be the minimal exhibit size.

(Illustrated and Permission by Jason Abdale)

-Due to paleopathological evidence, Tyrannosaurus rex are prone to illnesses and parasites that modern birds suffer from.

-Due to evidence showing that Tyrannosaurus has keen sense of smell, it is proper to use scent as a means of enriching the animal's life.  It could be done by both placing scents in it's enclosure and having an elevated structure (a hill or platform) so that the rex can take in the smells in the air, which originated from miles away.

-Much like how it is done for modern large predators, it should be taken to consideration that the rex would need a 1-3 day fasting each week.

-Juvenile tyrannosaurus rex have shown that between 14 to 18 years of age, they experience a dramatic growth spurt from 4,000 lbs to 9,200 lbs, which is 1,300 lbs a year.  When this growth spurt comes up, calculations on the nutrition needs to sustain this growth spurt is needed.

-Tyrannosaurus rex has been found that it's binocular vision is in fact not only better than a human's, but better than a hawk's or eagle's as well.  Studies have shown that it could discern objects about 3.7 miles away.  In consideration to it's welfare in captivity, a hill would be needed so that the rex can be enriched by the surrounding area by both scents and sights.

-Due to the length of it's cochlea (the spiral part of the inner ear), the t-rex has a strong sense of hearing and can even detect low frequency sounds.  There is consideration that low frequency sounds are important for behavioral reasons, much like how it is for elephants and whales.  Both sound sensitivity and behavior applications on the tyrannosaurus would need to be considered and studied.

-Due to studies done on related species and on it's brain size, it is definitely possible that Tyrannosaurus rex expressed complex behavior and may have hunted in packs.  While this is in debate, it's something to consider for the tyrannosaur's social and mental needs.  Most likely, introductions to different individual tyrannosaurs should be done when the animals are young in age (e.g. preteen age).

-Due to the evidence that Tyrannosaurus rex is capable of complex behavior, it seems quite possible that it could be target trained, much like how many modern day animals are.  The training can be useful for not just reinforcing desirable behaviors, but also easier health evaluations and even act as an enrichment for the rex.

Zoo-keeper target training a sealion (Cincinnati Zoo Blog)
-In understanding pathology with reproductive organs and related, researching on ratite (ostrich, emu, etc.) reproduction pathology will be needed.

-Due to the Tyrannosaurus being so top heavy, any kind of fall could kill it.  So, having slick-proof flooring is an immense need.

-Due to fossil evidence of several related species and actual skin impressions of the t. rex, the animal was primarily scaly (with scales like that of chicken's feet and legs, rather than that of reptiles) at adulthood.  But it is possible that they are born with down feathers to keep themselves warm until they get big enough.


-While they are laying eggs and molting, their demand for calcium will increase, so supplementation for calcium via oysters shells, limestone, or calcium powder developed for zoos (the earlier two were developed for chickens and other poultry) should be considered.

-Along with calcium needs, the digestive system of the velociraptor would perhaps be similar to that of REAL raptors or bird-of-prey (e.g., hawks and eagles).  So, with that in mind, the velociraptor's diet would need bone, internal organs, feathers, hides; basically roughage to sustain a healthy digestive system.

-Fossil evidence has shown that some members of Dromeaosaur family (especially the young) are capable of climbing trees, would perhaps be preferable to include logs or climbing structures to lower their stress levels and increase their enrichment.
Young Deinonychus specimen in Braunschweigisches LandesMuseum, Germany
(Photo from Scientific American)
-Considering that the velociraptor came from a dry desert environment*, humidity levels should be an issue to consider.
*Confirmed by MattPat in his video: "Film Theory: How to SAVE Jurassic Park (Jurassic World)"

-Scientists believe that the velociraptor's metabolism, growth rate, feathers, nasal passages, and bone structure (along with that of it's dromeaosaur relatives and 'primitive' birds) are akin to that of the New Zealand bird, the kiwi.  So, studying the kiwi's needs (food, water, medication, etc.) would be a good guide to knowing the needs of velociraptor.

-Sclerotic rings in the eye sockets indicate that the Velociraptor is nocturnal, which would indicate that the raptor is color-blind.  Also, it would also need a large enough nest box or chamber that is free of direct light.


-Much like mammalian megafauna of today, foot care is essential (from clipping their claws to trimming the extra skin of their soles).  Training of the sauropod's cooperation is a must since there would be no restraining equipment in existence that could hold on or down a fully-grown apatosaurus.  Best chances are to train the sauropod at a young age.

-In bird terms, apatosaur hatchlings would perhaps be considered precocial, meaning that the young are relatively mature and mobile at the moment of hatching.  Along with that, they are most likely nidifugous, meaning that they'll leave the nest shortly after hatching.

-The incubation length of sauropod eggs seem to be from 65 to 82 days (between 2-3 months).

-When being serious in obtaining and having one or more apatosaurs, planning for their future MUST be done.  The the maximum age of when you could be able to move them via truck/train would be 5 years of age (*weight at that age).  Past this age, the animal is too large to be moved via truck or train.  Only other way to do it is to either walk the animal to the now location or by cargo boat that could carry the sauropod.

-When born, apatosaurus would definitely have a endothermic-like (warm-blooded) metabolism and would grow fast for it.  But when it gets to a certain age or size, their metabolism slows down to the point that they become ectothermic (cold-bodied).

=More will come=

*This will be focusing on a more broader and general overview of hadrosaurs as a whole instead being very species specific.

Various Species of Hadrosaurs (from the Dinosaurs: Living Monsters of the Past by Michael Benton)

-Wood has been found within hadrosaur dung.  While debatable, it maybe possible that wood could be an essential part of some hardosaurs' diets.  While possibly debatable as well, it would seem reasonable to include pelleted feed that is developed for captive moose (which includes 22.5% sawdust due to wood being an important part of a moose's diet) when planning a diet for hadrosaurs.

A Edmontosaurus specimen called LACM 23502 shows
that the species had a more hooked beak, which suggests
that (along with coprolites or fossilized dung) it was a
browser (
-Due to their size, beaks, dentition, and physiology, hadrosaurs have a much broader feeding than other ornithischian (bird-hipped) dinosaurs.  Meaning that they can both graze on low ground plants (e.g. ferns, horsetails, and possibly grass) and browse on bushes and trees.  Percentage of grazing vs browsing behavior and feeding would most likely vary between species.  It was suggested that in the Late Creatceous, hadrosaurs browsed on low-growing shrubs and trees that ceratopsians couldn't reach.  This should be in consideration when placing them into an environment, especially in watching out for poisonous plants.

-Along with plant material, it is shown that hadrosaurs will occasionally feast upon crustaceans for possible additional protein and for calcium supplement for laying eggs (much like modern birds), possibly during breeding season and laying eggs.  For both, it would be needed to supplement their feed with seafood byproducts (for protein) and limestone/oyster shells (for calcium) during the breeding season.

-Some species would prefer nesting uplands lowlands (Parasaurolophus and Brachylophosaurus), whereas other species would prefer coastal plains (Edmontosaurus).  It has been suggested that behavior, diet, soil condition, and competition between dinosaur species all potentially influenced where hadrosaurs nested.

-With consideration to the studies of the Maiasaura, it's most likely that most (if not all) hadrosaur hatchlings are altricial, meaning that incapable of moving around on their own soon after hatching and need to fed and tended to for a long period of time.  Along with that, it might be indicated that hadrosaur young might also be nidicolous, meaning that they stay in their place of birth for an extended period of time to develop.

-Paleopathological research shows that it is common for hadrosaurs to suffer from ostesochondrosis, an orthopedic disease occur in the joints of rapidly growing animals, usual symptoms include interruption of the bone's blood supply, local bone necrosis, and regrowth.  Treatment applications and preventions on hadrosaurs would need research.

-Additional paleopathological have shown that hadrosaurs can be infected by ameloblastoma and septic arthritis in the anterior extremities (fun fact: both were the first to be discovered in any dinosaur genera).  Treatment applications on hadrosaurs for the said diseases will need to be researched on.

-Studies on the hadrosaur's paleoenvironment shows that hadrosaurs are mostly found on coasts and deltas; they would even live in alluvial plains.  All this would need to taken to consideration in both designing a hadrosaur habitat or even planning on where to set up a location to have hadrosaurs.


-Due to the Gallimimus seemingly coming from a desert environment, it may be wise to make sure that the Gallimimus is in a dry environment.  To not do so would possibly lead to fungal infections at their feet, possible 'rain rot' (a condition donkeys in wet environments unsheltered would suffer, basically skin and fur absorb so much water that it all 'rots' out in time), and other moisture related illnesses.  If located in a moist area, shelter and high ground will be required.

-With evidence showing that they are feathered and lay eggs, calcium supplementation is advisable for egg laying and molting of feathers.

-After correctly looking at the grooves within the beaks of ornithomimids, it's shows that the gallimimus and kin are more herbivorous.  In consideration to this, it seems probable to their diet requirements would be a kin to emus or chickens, feasting on plant matter with some insects and other animal-based protein.

-Due to the existence of gastroliths within many ornithomimids, it's most likely Gallimimus would need gastroliths to grind tough plant material (much like ostriches do today).


Pachycephalosaurus (Illustrated and Permission by Jason Abdale)

-Due to their characteristic thick skull, it is undoubtable that the pachycephalosaurs would've had a high calcium requirement in it's diet.  It would be best to start off with the usual Calcium:Phosphorus ratio of 2:1 in it's diet, which is the average requirement for most animals.  Only with further testing and research can you increase the calcium intake.  Reason being is that in a load of animals, too much calcium can be cause them several medical issues (such as urinary calci or "water belly" in sheep and goats).

-If the 'bonehead' is covered by a keratin casting (like the shell of a turtle or armadillo), it would perhaps need mineral oil rubbed on it to be clean and healthy looking.

-During breeding season, to prevent damage to both animal and facilities, keep males separated and out of sight of each other (out of viewing distance from each other or solid visual blocks).

In General

-Unwanted hatchlings or fertile eggs can be avoided via separating males and females.  But if separation can't be avoided and if there are risks of uterus infections and hormone-related behavioral issues, spaying and neutering could be a possibility.  Since both have been done on both birds and reptiles (done quite often on green iguanas), it could be possible to do so with dinosaurs.  Although, whether their reproductive organs are more like birds or reptiles can be somewhat debatable and it might vary from different dinosaur groups.  More research would be needed before considering.

-Much like modern birds, dinosaurs would definitely suffer from oviduct infections, egg retention, and yolk sac retention/infection.

-Much like birds, dinosaurs would suffer from prolapse of the phallus due to disease, climatic extremes, and egg-laying.

-In researching for diseases that can infect the general dinosaur species, it is best to look up on avian (cryptococcosis, histoplasmosis, tuberculosis, psittacosis) and reptilian diseases (salmonella, botulism, leptospirosis, campylobacterosis).

-When it comes to feeding large dinosaurs, you need to take advice from feeding large mammals when feeding in bulk.  However, with nutrition, you would need research about avian (bird) nutrition.  On an added note, to help young herbivorous dinosaurs, it might be advisable to feed them plants that have been grown in conditions similar to atmospheric conditions of Jurassic times, such as higher carbon dioxide levels (for the plants had higher levels of energy and nutrients than that of today).

-In hand-raising captive dinosaurs, it would be important to raise them with at least one other member of their species (or related species) so they can develop better social skills with others of their own kind and avoid most abnormal behaviors.  This would be especially important for species that are proven to be social (e.g. hadrosaurs, tyrannosaurs, ceratopsians, etc.).

=Special Thanks=

Along with my own personal research, I also have to thank others for additional research and information that have helped me develop the science within this post and idea.  So, time to give credit where credit it due:

  • A special thanks to Rogelio A. Reyna-Hernández, also known as RogerRex in DeviantArt, for his studies on hadrosaurs and resources on articles of the said species on their diets, paleopathologies, and paleoenvironments.
  • A special thank you to Jason Abdale, a historian who is also an paleo-illustrator, for giving me permission to use some of his illustrations (Tyrannosaurus rex, Triceratops, and Pachycephalosaurus with his name on them) for this article.  To see where these illustrations come from and to see more of his marvelous work and articles, look up on his blog called Dinosaurs and Barbarians.


Anné, J., Hedrick, B. P., & Schein, J. P. (2016). First diagnosis of septic arthritis in a dinosaur. Royal Society open science, 3(8), 160222.

Arbour, V.M.; Mallon, J.C. (2017). "Unusual cranial and postcranial anatomy in the archetypal ankylosaur Ankylosaurus magniventris". FACETS. 2 (2): 764–794

Chin, K.; Feldmann, R. M.; & Tashman, J. N. (2017). «Consumption of crustaceans by megaherbivorous dinosaurs: dietary flexibility and dinosaur life history strategies». Scientific reports 7, 11163

Coombs,  W. P. Jr. 1978.  Theoretical aspects of cursorial adaptations in dinosaurs.  Quarterly Review of Biology 53: 393-418.

 Curry, K.A. (1999). "Ontogenetic histology of Apatosaurus (Dinosauria: Sauropoda): new insights on growth rates and longevity". Journal of Vertebrate Paleontology19 (4): 654–665.

Dumbravă, M. D., Rothschild, B. M., Weishampel, D. B., Csiki-Sava, Z., Andrei, R. A., Acheson, K. A., & Codrea, V. A. (2016). A dinosaurian facial deformity and the first occurrence of ameloblastoma in the fossil record. Scientific reports, 6, 29271.

Eberth, D. A., Ryan, M. J., & Chinnery-Allgeier, B. J. (2010). A review of ceratopsian paleoenvironmental associations and taphonomy. New perspectives on horned dinosaurs. Edited by MJ Ryan, BJ Chinnery-Allgeier, and DA Eberth. Indiana University Press, Bloomington, IN, 428-446.

Erickson, Gregory M.; Makovicky, Peter J.; Currie, Philip J.; Norell, Mark A.; Yerby, Scott A.; Brochu, Christopher A. (2004). "Gigantism and comparative life-history parameters of tyrannosaurid dinosaurs". Nature. 430 (7001): 772–775.

Gates, T. A., & Sampson, S. D. (2007). A new species of Gryposaurus (Dinosauria: Hadrosauridae) from the late Campanian Kaiparowits Formation, southern Utah, USA. Zoological Journal of the Linnean Society151(2), 351-376.

"Maiasaura," Dodson, et al. (1994); pages 116-117.

 Mallon, Jordan C.; Evans, David C.; Ryan, Michael J.; Anderson, Jason S. (2013). "Feeding height stratification among the herbivorous dinosaurs from the Dinosaur Park Formation (upper Campanian) of Alberta, Canada". BMC Ecology. 13: 14

Paul, Gregory S. (2002). Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds. Baltimore: Johns Hopkins University Press.

Prieto-Márquez, A. (2014). Skeletal morphology of Kritosaurus navajovius (Dinosauria: Hadrosauridae) from the Late Cretaceous of the North American south-west, with an evaluation of the phylogenetic systematics and biogeography of Kritosaurini. Journal of Systematic Palaeontology, 12(2), 133-175.

Stevens, Kent A. (April 1, 2011) The Binocular Vision of Theropod Dinosaurs.Retrieved July 29, 2013.

Rothschild, Bruce; Tanke, Darren H. (2007). "Osteochondrosis is Late Cretaceous Hadrosauria". In Carpenter Kenneth (ed.). Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs. Bloomington and Indianapolis: Indiana University Press. pp. 171–183.

Ruxton, Graeme D.; Birchard, Geoffrey F.; Deeming, D. Charles (2014). "Incubation time as an important influence on egg production and distribution into clutches for sauropod dinosaurs". Paleobiology40 (3): 323–330.

Schweitzer MH, Wittmeyer JL, Horner JR (June 2005). "Gender-specific reproductive tissue in ratites and Tyrannosaurus rex". Science. 308 (5727): 1456–60. doi:10.1126/science.1112158. PMID 15933198. Retrieved October 5, 2008.

Tanke, D.H. and Brett-Surman, M.K. 2001. Evidence of Hatchling and Nestling-Size Hadrosaurs (Reptilia:Ornithischia) from Dinosaur Provincial Park (Dinosaur Park Formation: Campanian), Alberta, Canada. pp. 206-218. In: Mesozoic Vertebrate Life—New Research Inspired by the Paleontology of Philip J. Currie. Edited by D.H. Tanke and K. Carpenter. Indiana University Press: Bloomington. xviii + 577 pp.

University of Leeds. "Growing a dinosaur's dinner." ScienceDaily. ScienceDaily, 13 July 2018. <>

Wallis, Paul (2012-06-11). "Op-Ed: T. Rex pack hunters? Scary, but likely to be true". Retrieved 2015-12-23.

Williams, V. S.; Barrett, P. M.; & Purnell, M. A. (2009). «Quantitative analysis of dental microwear in hadrosaurid dinosaurs, and the implications for hypotheses of jaw mechanics and feeding». Proceedings of the National Academy of Sciences 106 (27): 11194-11199.

Witmer, Lawrence M.; Ridgely, Ryan C. (September 2009). "New Insights Into the Brain, Braincase, and Ear Region of Tyrannosaurs (Dinosauria, Theropoda), with Implications for Sensory Organization and Behavior". The Anatomical Record. 292 (9): 1266–1296.

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