DINOSAUR TIME
Interactive Dinosaur Timeline
Follow dinosaur evolution from its Triassic origins through Jurassic diversification to the end-Cretaceous impact and the survival of birds.
Deep time, on the same scale
See the distance in time.
150 Ma
Jurassic · Current cursor
Ma = million years ago; older to the left. Mixed ranks: Precambrian is an informal span, Paleozoic and Cenozoic are eras; the Mesozoic is expanded into its three periods.
Distance between selected events
135.4
million years
A · Jurassic begins · 201.4 Ma
B · K–Pg extinction boundary · 66 Ma
|201.4 − 66| = 135.4 Ma
Event comparison is independent of the viewing window.
Prints current values. Expand teacher answers to include them.
Classroom investigation · suggested ages 10–14
Predict. Measure. Explain.
Goal: read a proportional timeline, calculate durations and explain how zoom changes our perception.
- Which Mesozoic period lasted longest? Predict from the bands, then calculate.
- How many years separate your selected events? Show how to convert from Ma.
- Switch to Earth history. Why does the Mesozoic look narrow? Does that make dinosaur history short?
Teacher answers & discussion
- Triassic ≈ 50.502 Myr; Jurassic ≈ 58.3 Myr; Cretaceous ≈ 77.1 Myr. The Cretaceous is longest.
- 135.4 × 1,000,000 ≈ 135,400,000 years. Calculation does not remove uncertainty from approximate dates.
- A wider window compresses the same duration. The Mesozoic spans about 185.902 million years, about 4.04% of this 4.6-billion-year model. Narrow does not mean brief.
Geological boundaries use central values from ICS 2026/06; dating uncertainties are not plotted. Early dinosaurs use a rounded 230 Ma marker. The 4600 Ma Earth origin is a classroom convention, not a formal stratigraphic boundary.
ICS 2026/06 ↗ · USGS: age of Earth ↗ · NHM: dinosaur origins ↗
Free to project and print this activity for non-commercial teaching with credit and sources retained. Ages and timing are planning suggestions, not classroom-trial results. AI-assisted; independent expert review is not claimed. More teaching materials ↗
Late Triassic
Origins
The earliest widely accepted dinosaurs were small members of ecosystems still dominated by other archosaurs.
Triassic–Jurassic boundary
Opportunity after extinction
The end-Triassic extinction removed many competitors and dinosaur lineages expanded into new terrestrial roles.
Middle–Late Jurassic
Giants and specialised bodies
Sauropods, plated stegosaurs and large theropods formed familiar Jurassic ecosystems.
Early Cretaceous
Feathers and flowering landscapes
Feathered dinosaurs diversified while flowering plants began transforming terrestrial food webs.
Late Cretaceous
Regional radiations
Fragmented continents supported distinctive tyrannosaurs, horned dinosaurs, hadrosaurs and titanosaurs.
K–Pg boundary
Impact and survival
The Chicxulub impact collapsed food webs. All non-avian dinosaurs disappeared; birds carried Dinosauria onward.
Boundaries follow the ICS 2026/06 chart; event sections are not drawn to time scale. T. rex and Triceratops at 66 Ma illustrate extinction; other bird lineages survived. ICS chart ↗ · NHM: surviving birds ↗