Where the facts come from
Every factual claim on this site links to its source. This is the full list.
How we checked
Each fact was written alongside its source. Our build script stores the source text and, for every fact, checks that the key words and figures really appear in it. 109 of 109 checks passed when this site was last built (October 2026). Where we couldn’t find a source we could read, we left the claim out.
What we use
Only three kinds of source: the Natural History Museum in London, the Smithsonian (its collection records, its museum blog and Smithsonian Magazine), and peer-reviewed scientific papers, which we read in full. Two state symbols come from the official South Dakota and Wyoming government sites.
Figures that change
Palaeontology moves quickly. New fossils turn up and new studies revise old ideas, especially for size and for debates like Torosaurus. Facts like these are marked “checked 27 Oct 2026” so you know how fresh they are, and we say where estimates vary or scientists disagree. Dates of discoveries and names, such as Triceratops being named in 1889, don’t change.
Natural History Museum (13)
- Natural History Museum: Ankylosaurus (Dino Directory) (1 fact)
- Natural History Museum: Centrosaurus (Dino Directory) (2 facts)
- Natural History Museum: Chasmosaurus (Dino Directory) (2 facts)
- Natural History Museum: Edmontosaurus (Dino Directory) (1 fact)
- Natural History Museum: How an asteroid ended the age of the dinosaurs (3 facts)
- Natural History Museum: Pachycephalosaurus (Dino Directory) (2 facts)
- Natural History Museum: Pentaceratops (Dino Directory) (2 facts)
- Natural History Museum: Protoceratops (Dino Directory) (2 facts)
- Natural History Museum: Psittacosaurus (Dino Directory) (2 facts)
- Natural History Museum: Styracosaurus (Dino Directory) (4 facts)
- Natural History Museum: Torosaurus (Dino Directory) (3 facts)
- Natural History Museum: Triceratops (Dino Directory) (30 facts)
- Natural History Museum: Tyrannosaurus (Dino Directory) (2 facts)
Smithsonian (7)
- Smithsonian Magazine: Meet the dinos of “Deep Time”, 2019 (5 facts)
- Smithsonian Magazine: New study says Torosaurus = Triceratops, 2010 (2 facts)
- Smithsonian Magazine: Relax, Triceratops really did exist, 2010 (1 fact)
- Smithsonian Magazine: The Torosaurus identity crisis continues, 2012 (4 facts)
- Smithsonian NMNH collection record: Triceratops horridus (“Hatcher”), USNM PAL500000 (1 fact)
- Smithsonian Voices (NMNH): An elegy for Hatcher the Triceratops, 2018 (9 facts)
- Smithsonian Voices (NMNH): Q&A on the T. rex’s new pose, 2018 (1 fact)
Peer-reviewed papers (7)
- Erickson et al. (2015), Wear biomechanics in the slicing dentition of Triceratops, Science Advances (4 facts)
- Farke (2011), Nedoceratops hatcheri, PLOS ONE (1 fact)
- Farke, Wolff & Tanke (2009), Evidence of combat in Triceratops, PLOS ONE (2 facts)
- Horner & Goodwin (2006), Major cranial changes during Triceratops ontogeny, Proc. R. Soc. B (10 facts)
- Longrich & Field (2012), Torosaurus is not Triceratops, PLOS ONE (4 facts)
- Maiorino, Farke, Kotsakis & Piras (2013), Is Torosaurus Triceratops?, PLOS ONE (1 fact)
- Scannella, Fowler, Goodwin & Horner (2014), Evolutionary trends in Triceratops, PNAS (6 facts)