Prehistoric Animal Museum

Meet today’s friendRay-finned fish

Xiphactinus

Large teeth inside a big mouth, with small fins beneath the body.

Xiphactinus had large teeth, and some individuals were over five metres long. Could a fish that big fit inside a tiny fish tank?

Still model of Xiphactinus on a transparent background

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Xiphactinus

Preparing the Xiphactinus exhibit.

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Guide for grown-ups

When it lived: Late Cretaceous
Where fossils were found: Western Interior Seaway, North America
Body length: 5.5 m (about 18 ft)
Diet: Meat-eater
What kind of animal?: Ray-finned fish. Xiphactinus was a meat-eating fish from ancient seas, with large teeth inside a big mouth.

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Narration transcript

Xiphactinus had large teeth, and some individuals were over five metres long. Could a fish that big fit inside a tiny fish tank?

Research notes about Xiphactinus

Research summary

Fossils of Xiphactinus date to the Late Cretaceous and have been found in Western Interior Seaway, North America.

Learning from fossils

Individuals varied in size, and some large Xiphactinus grew to more than five metres long.

Scientific sources

Xiphactinus at the North Dakota Geological SurveyAccessed 2026-10-22

Leon Made This compiled these research notes from public museum resources and scientific papers while preserving uncertainty in the reconstruction. Last reviewed 2026-10-22.

3D model and asset credits

Xiphactinus: “Xiphactinus” by Julian Johnson-Mortimer, CC BY 4.0; modified for the Prehistoric Animal Museum. Creative Commons Attribution 4.0 International

Open source and licensing

The code is licensed under AGPL-3.0. Original science writing and project artwork use CC BY-NC-SA 4.0 for non-commercial sharing. The brand policy prevents impersonation, and third-party assets keep their original licences.

View the GitHub project Read the full licensing notes

Official source

Made by Leon Made This

Prehistoric Animal Museum is made and maintained by Leon Made This. Use these addresses to verify the official project and its creator.

Official Prehistoric Animal Museumhttps://leon-made-this.work/museum/en/Leon's personal websitehttps://leon-made-this.work/

More information is available below.

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Leon Made This

About this museum

A little museum made by a developer dad for his daughter

I’m Leon, a developer and a dad. When my daughter was three, dinosaur chases on television frightened her, so I made a 3D prehistoric animal museum where she could look quietly and listen only when she wanted to.

The museum is free, with no sign-up, adverts or visitor tracking. Finding one interesting detail at a time is plenty.

Official source

Made by Leon Made This

Prehistoric Animal Museum is made and maintained by Leon Made This. Use these addresses to verify the official project and its creator.

Official Prehistoric Animal Museumhttps://leon-made-this.work/museum/en/Leon's personal websitehttps://leon-made-this.work/

View the source on GitHub Read the licence and asset notes