Size It Up

ALL ANSWERS · DINOSAURS · DAILY No. 15 · SEPTEMBER 18, 2026

Size It Up Dinosaurs answer: September 18

The five Dinosaurs silhouettes for September 18, with the true sizes. If you have not played yet, this page is a spoiler — play these five first, then come back to argue with the numbers.

Day 15 ran from a psittacosaurus (2 m) to a mamenchisaurus (22 m). The widest gap was round 4, Therizinosaurus against Anchisaurus, at 5.0×; the closest call was round 2, Ceratosaurus against Europasaurus, only 1.1× apart — the kind of round that separates a 90 from a 60.

  1. ROUND 1

    Psittacosaurus Psittacosaurus mongoliensis vs Stegosaurus Stegosaurus stenops

    Stegosaurus · reference · 9 m
    Psittacosaurus · true length · 2 m

    4.5× shorter than the stegosaurus

    Psittacosaurus is represented here by a selected estimated total length of 2 m. Dinosaur reconstructions vary; this is the source value used for this comparison.

  2. ROUND 2

    Ceratosaurus Ceratosaurus nasicornis vs Europasaurus Europasaurus holgeri

    Europasaurus · reference · 6.2 m
    Ceratosaurus · true length · 7 m

    1.1× longer than the europasaurus

    Ceratosaurus is represented here by a selected estimated total length of 7 m. Dinosaur reconstructions vary; this is the source value used for this comparison.

  3. ROUND 3

    Yutyrannus Yutyrannus huali vs Spinosaurus Spinosaurus aegyptiacus

    Spinosaurus · reference · 14 m
    Yutyrannus · true length · 7.5 m

    1.9× shorter than the spinosaurus

    Yutyrannus is represented here by a selected estimated total length of 7.5 m. Dinosaur reconstructions vary; this is the published estimate used for this comparison.

  4. ROUND 4

    Therizinosaurus Therizinosaurus cheloniformis vs Anchisaurus Anchisaurus polyzelus

    Anchisaurus · reference · 2 m
    Therizinosaurus · true length · 10 m

    5.0× longer than the anchisaurus

    Therizinosaurus is represented here by a selected estimated total length of 10 m. Dinosaur reconstructions vary; this is the source value used for this comparison.

  5. ROUND 5

    Mamenchisaurus Mamenchisaurus hochuanensis vs Kentrosaurus Kentrosaurus aethiopicus

    Kentrosaurus · reference · 5 m
    Mamenchisaurus · true length · 22 m

    4.4× longer than the kentrosaurus

    Mamenchisaurus is represented here by a selected estimated total length of 22 m. Dinosaur reconstructions vary; this is the published estimate used for this comparison.

Beat these tomorrow

Every round is worth up to 100 points: within 6% of the true size scores 100, half or double scores 45, five times off scores zero. The daily puzzle is the same five for everyone and refreshes at midnight in your time zone; if you want more than five, Size It Up Unlimited draws fresh pairs from the whole library for as long as you like.

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