Body length
InferredAbout 0.65–0.75 m (known individual estimates)
Original reconstructions of the largest known individuals; histology identifies a near-sized specimen as a young adult, not a proven species maximum. [D1]
EXHIBIT 237
Fruitadens
Fruitadens haagarorum
Dinosaur
Fruitadens was a tiny heterodontosaurid with teeth that suggest a possible mixed diet. [2]
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 Fruitadens 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. [2]
Source-informed reconstruction. Appearance evidence [2]. 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 Fruitadens haagarorum; 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.
PERIODLate Jurassic[1]
DIETOmnivoreEvidence and uncertainty in the dossier
TOTAL LENGTH0.65–0.75 mEstimate scope matters
FOSSILS FOUNDUnited States[1]
MEET THE ANIMAL
Meet Fruitadens
Fruitadens was a very small dinosaur from western Colorado during the Late Jurassic. Researchers estimated the largest known individuals at roughly 65 to 75 centimeters long and around half to three-quarters of a kilogram. Thin sections of a similarly sized bone showed a young adult in its fifth year. This helps explain why small size cannot simply be dismissed as a baby dinosaur. [D1]
Its teeth and jaws provide clues to a possible mixed diet. Fruitadens lacked the impressive upper tusks seen in some relatives, and its lower canine-like tooth was modest. Researchers reconstructed a jaw suited to relatively quick, wide opening. Plants and small invertebrates are plausible foods, but that conclusion comes from anatomy and mechanics rather than a preserved stomach full of food. [D2]
The Natural History Museum of Los Angeles County includes Fruitadens in its Dinosaur Hall and compares its size with a chicken. Such comparisons help visitors picture an animal that could easily be overshadowed by giant skeletons. They are useful introductions, while the scientific details still depend on the actual teeth, limb fragments and growth evidence rather than the size of a familiar living animal. [D3]
PREHISTORIC ANIMAL DOSSIER
A life in profile.
The animal, the evidence, and the questions still open.
Jaw mechanics suggest flexible feeding, while bone histology helps distinguish small young adults from juveniles. [D2]
Profile scope: Genus — Fruitadens haagarorum; partial Fruita fossils including holotype LACM 115747. [D1]
- Time
- Late Jurassic
- 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
InferredAbout 0.5–0.75 kg (reconstructed individuals)
Estimates from the original study, not measured weights or a species-wide range. [D1]
Diet and feeding
InferredPossible mixed diet
Tooth form and jaw mechanics suggest plants and small invertebrates; exclusive herbivory or a particular meal is not demonstrated. [D2]
Habitat and setting
Source supportedWestern Colorado Morrison setting
Fossils come from the Fruita locality in the lower Brushy Basin Member, early Tithonian Late Jurassic. [D1]
Movement
InferredSmall bipedal reconstruction
Preserved hindlimb and ankle anatomy supports two-legged movement; speed is not measured. [D2]
Recognizable anatomy
Source supportedSmall, varied teeth
There is no large upper tusk; the lower canine-like tooth is no taller than the largest cheek teeth. [D2]
Reproduction & life together
Reproduction and nesting
Not establishedNot established here
Reviewed material provides no assigned egg, nest or embryo. [D1]
Mating and courtship
Not establishedNot established here
Reviewed skull and jaw evidence does not reveal mating displays. [D2]
Social behavior
Not establishedNot established here
Several museum specimens do not establish a living group or family structure. [D3]
Dossier research & sources
Sources and inspection notes for the claims in this profile.
- Lower limits of ornithischian dinosaur body size inferred from a new Upper Jurassic heterodontosaurid from North America (Butler et al., 2009/2010)Proceedings of the Royal Society B 277:375–381; doi:10.1098/rspb.2009.1494 · Accessed 2026-10-06Full original text, type/locality, diagnosis and histology inspected. LACM115747 type; LACM115727 near type size is fifth-year young adult. Largest known individuals estimated 65–75 cm and 0.5–0.75 kg. Fruita western Colorado, basal Brushy Basin Morrison, early Tithonian; estimates are fossil-individual reconstructions, not complete maturity-qualified species ranges. · Inspected: page
- Anatomy and Cranial Functional Morphology of the Small-Bodied Dinosaur Fruitadens haagarorum from the Upper Jurassic of the USA (Butler et al., 2012)PLOS ONE 7(4):e31556 · Accessed 2026-10-06Full original paper retained; diagnosis, teeth, jaw mechanics and dietary discussion inspected. No upper caniniform; lower caniniform no larger than biggest cheek tooth, tiny anterior peg-like tooth. Rapid large-gape action and low wear suggest possible omnivory including plants/invertebrates, not a preserved meal. · Inspected: page
- Our 10-Year DinoversaryNatural History Museum of Los Angeles County · Accessed 2026-10-06Institutional Dinosaur Hall account inspected; Fruitadens display and chicken-size comparison. Museum display comparison does not supply measured adult size or direct feeding evidence. · Inspected: page
THE STORY IN THE FOSSILS
Evidence behind Fruitadens
The museum's chicken-size comparison makes the display accessible, while the measurements retain their individual-estimate scope. [3]
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.
- Lower limits of ornithischian dinosaur body size inferred from a new Upper Jurassic heterodontosaurid from North America (Butler et al., 2009/2010)Proceedings of the Royal Society B 277:375–381; doi:10.1098/rspb.2009.1494 · Accessed 2026-10-06Full original text, type/locality, diagnosis and histology inspected. LACM115747 type; LACM115727 near type size is fifth-year young adult. Largest known individuals estimated 65–75 cm and 0.5–0.75 kg. Fruita western Colorado, basal Brushy Basin Morrison, early Tithonian; estimates are fossil-individual reconstructions, not complete maturity-qualified species ranges. · Inspected: page
- Anatomy and Cranial Functional Morphology of the Small-Bodied Dinosaur Fruitadens haagarorum from the Upper Jurassic of the USA (Butler et al., 2012)PLOS ONE 7(4):e31556 · Accessed 2026-10-06Full original paper retained; diagnosis, teeth, jaw mechanics and dietary discussion inspected. No upper caniniform; lower caniniform no larger than biggest cheek tooth, tiny anterior peg-like tooth. Rapid large-gape action and low wear suggest possible omnivory including plants/invertebrates, not a preserved meal. · Inspected: page
- Our 10-Year DinoversaryNatural History Museum of Los Angeles County · Accessed 2026-10-06Institutional Dinosaur Hall account inspected; Fruitadens display and chicken-size comparison. Museum display comparison does not supply measured adult size or direct feeding evidence. · Inspected: page
KEEP EXPLORING
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