Body length
InferredAbout 2.1 m (reconstructed adult)
Applies to the original burrow-associated adult reconstruction, not a species-wide maximum. [D1]
EXHIBIT 236
Oryctodromeus
Oryctodromeus cubicularis
Dinosaur
Oryctodromeus is a small dinosaur whose fossils were found inside a matching underground burrow. [1]
TWO WAYS TO PICTURE THE PAST
Science & the silver screen
Compare the evidence with the familiar movie image. The illustrations are not to a shared scale.
01 / SOURCE-INFORMED RECONSTRUCTION
A life reconstruction from the evidence
Image unavailableIllustrative life reconstruction of Oryctodromeus in a period-appropriate environment; coloration and missing anatomy are interpretations.The exhibit and its credited image source remain available.
An illustrative reconstruction. Compare its anatomy with the evidence and limitations in the dossier. [3]
Source-informed reconstruction. Appearance evidence [3]. Original illustration; missing anatomy, coloration and scenery include interpretation.
Fossils constrain this life reconstruction. Missing anatomy, coloration and the environmental scene include interpretation; the dossier explains the evidence limits.
02 / MOVIE-STYLE INTERPRETATION
A cinematic imagination
Image unavailableIllustrative reconstruction of Oryctodromeus cubicularis; missing anatomy, pose, skin and colors are hypotheses.The exhibit and its credited image source remain available.
An illustrative reconstruction. Compare its anatomy with the evidence and limitations in the dossier. Lighting, coloration and scenery are artistic choices. This image does not document a fossil locality or behavior.
Original artwork · artistic interpretation.
Scientific view: source-informed reconstruction, credited paleoart or specimen-based imagery. Movie-style view: Original artistic interpretation. Reconstructions involve uncertainty.
PERIODEarly–Late Cretaceous[2]
DIETHerbivoreEvidence and uncertainty in the dossier
TOTAL LENGTH2.1–2.1 mEstimate scope matters
FOSSILS FOUNDUnited States[1]
MEET THE ANIMAL
Meet Oryctodromeus
Oryctodromeus offers a rare chance to connect a dinosaur with a place it used. Researchers found one adult and two juveniles in the end chamber of a fossil burrow in Montana. The tunnel dimensions fit the adult's reconstructed body. That combination supports the idea that these animals used underground shelter, rather than being unrelated bones accidentally found near a hole. [D1]
Later research described more burrows and fossil associations in Montana and Idaho. The rocks preserve different kinds of burial, including articulated skeletons and scattered remains. Repeated discoveries strengthen the shelter interpretation and suggest care of young animals. They still do not show a courtship dance, the shape of an Oryctodromeus egg, or how many dinosaurs usually traveled together above ground. [D2]
This animal was a small two-legged dinosaur with a remarkably long tail, not a prehistoric rabbit. The tail made up more than half its length and was supported by a network of hardened tendons. Researchers also examined limb bones from different growth stages. Bone tissue and growth lines help estimate how individuals grew while keeping that question separate from mating or nesting behavior. [D3]
PREHISTORIC ANIMAL DOSSIER
A life in profile.
The animal, the evidence, and the questions still open.
A long tail, unusual femoral heads and growth evidence complement the burrow discoveries. [D3]
Profile scope: Genus — Oryctodromeus cubicularis; Montana and Idaho material, including adult MOR 1636a and two juveniles. [D2]
- Time
- Early–Late Cretaceous
- Fossil locations in this exhibit
- United States
How to read the evidence
Source supported identifies a description documented by the cited source. Inferred marks a reconstruction or functional estimate. Debated marks competing interpretations. Not established means the sources reviewed for this dossier do not support a firm conclusion; it does not mean a behavior never occurred.
A size reference is an estimate, not a population range. Nesting evidence does not by itself establish courtship, mate choice, or lifelong pairing.
Body mass
Not establishedNot established here
Burrow-based mass inference is not adopted as a skeletal estimate. [D1]
Diet and feeding
InferredPlant feeding inferred
The original paper identifies a herbivorous ornithischian; a particular meal is not preserved. [D1]
Habitat and setting
InferredRiver-floodplain deposits and burrows
Montana Vaughn and Idaho Wayan records span Albian–Cenomanian contexts. Different burial facies are not all separate preferred habitats. [D2]
Movement
InferredSmall bipedal dinosaur
The skeleton combines a long tail with unusual femoral anatomy; burrowing does not imply a rabbit-like body or flexible short tail. [D3]
Recognizable anatomy
Source supportedLong tail with ossified tendons
The tail exceeds half the animal's length. Detailed reconstruction draws on more than the first partial burrow skeleton. [D3]
Reproduction & life together
Reproduction and nesting
InferredPossible care within dens
Additional adult–juvenile associations support a care interpretation; reviewed eggshells do not establish this genus's eggs or nesting arrangement. [D2]
Mating and courtship
Not establishedNot established here
Reviewed burrow and skeletal evidence does not reveal courtship displays or mating pairs. [D2]
Social behavior
InferredAdult–juvenile association
One adult and two juveniles shared the original burrow. Care is a reasonable inference; ordinary group size and cooperative behavior remain unknown. [D1]
Dossier research & sources
Sources and inspection notes for the claims in this profile.
- First trace and body fossil evidence of a burrowing, denning dinosaur (Varricchio, Martin and Katsura, 2007)Proceedings of the Royal Society B 274:1361–1368 · Accessed 2026-10-06Original full text inspected through author-uploaded copy. MOR 1636a adult and MOR 1636b two juveniles in terminal burrow chamber; reconstructed adult 2.1 m, tail about 1.25 m. 22–32 kg is inferred from burrow cross-section allometry, not skeletal volumetry. Adult–juvenile care is inferred, not an identified mother. · Inspected: page
- Taphonomy of and new burrows from Oryctodromeus cubicularis ... (Krumenacker et al., 2019)Palaeogeography, Palaeoclimatology, Palaeoecology 530:300–311; doi:10.1016/j.palaeo.2019.05.047 · Accessed 2026-10-06Original abstract, introduction, accessible taphofacies and conclusion passages inspected. Albian–Cenomanian Wayan/Vaughn; two new burrows and additional adult–juvenile associations. Nearby eggshell ootaxa are not identified as Oryctodromeus eggs. · Inspected: excerpt
- Osteology, phylogeny, taphonomy, and ontogenetic histology of Oryctodromeus cubicularis (Krumenacker, 2017)Montana State University doctoral dissertation · Accessed 2026-10-06Institutional original dissertation abstract inspected: small biped; tail exceeds half body length, sheathed by ossified tendons; unusual femoral heads. Seven sampled limb elements document growth stages, not reproductive maturity. Full dissertation download identified but not used to claim uninspected chapters. · Inspected: abstract
THE STORY IN THE FOSSILS
Evidence behind Oryctodromeus
The burrow fits the adult's proportions, making a denning interpretation stronger than a story based on bones alone. [1]
Later discoveries strengthen the burrow association without establishing a complete picture of social organization. [2]
A note on scale and time
The dossier identifies the scope of each reference estimate. A mount, an individual fossil and a species-wide adult range are different measurements. Comparison metrics remain unavailable where adult scope has not been established. Unknown does not mean zero.
Sources & editorial notes
Sources support the stated claims and scopes. Refer to the evidence notes for uncertainty.
- First trace and body fossil evidence of a burrowing, denning dinosaur (Varricchio, Martin and Katsura, 2007)Proceedings of the Royal Society B 274:1361–1368 · Accessed 2026-10-06Original full text inspected through author-uploaded copy. MOR 1636a adult and MOR 1636b two juveniles in terminal burrow chamber; reconstructed adult 2.1 m, tail about 1.25 m. 22–32 kg is inferred from burrow cross-section allometry, not skeletal volumetry. Adult–juvenile care is inferred, not an identified mother. · Inspected: page
- Taphonomy of and new burrows from Oryctodromeus cubicularis ... (Krumenacker et al., 2019)Palaeogeography, Palaeoclimatology, Palaeoecology 530:300–311; doi:10.1016/j.palaeo.2019.05.047 · Accessed 2026-10-06Original abstract, introduction, accessible taphofacies and conclusion passages inspected. Albian–Cenomanian Wayan/Vaughn; two new burrows and additional adult–juvenile associations. Nearby eggshell ootaxa are not identified as Oryctodromeus eggs. · Inspected: excerpt
- Osteology, phylogeny, taphonomy, and ontogenetic histology of Oryctodromeus cubicularis (Krumenacker, 2017)Montana State University doctoral dissertation · Accessed 2026-10-06Institutional original dissertation abstract inspected: small biped; tail exceeds half body length, sheathed by ossified tendons; unusual femoral heads. Seven sampled limb elements document growth stages, not reproductive maturity. Full dissertation download identified but not used to claim uninspected chapters. · Inspected: abstract
KEEP EXPLORING
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