{
  "id": 177419,
  "title": "Fossilien: Warum Dinosaurier nie so klein waren wie eine Maus",
  "url": "https://urgent.news/2026/08/05/fossilien-warum-dinosaurier-nie-so-klein-waren-wie-eine-maus",
  "topic": "science",
  "section": "Science",
  "published": "2026-08-05T14:01:15.000Z",
  "source": {
    "name": "Handelsblatt",
    "slug": "handelsblatt",
    "url": "https://www.handelsblatt.com/technik/forschung-innovation/fossilien-warum-dinosaurier-nie-so-klein-waren-wie-eine-maus/100245337.html"
  },
  "original_language": "de",
  "account": "Dinosaurier, known as the giants of the prehistoric era, did not always grow to monstrous sizes. While some species were as large as modern cows, others were no bigger than a fox. However, this trend of increasing size continued, particularly among the sauropods like the Brontosaurus, Brachiosaurus, and Diplodocus. The question remains as to why dinosaurs never became small enough to be as diminutive as a mouse. A research duo from the American Museum of Natural History and Princeton University delved into this mystery by analyzing the evolution of body size in vertebrates through a mathematical model. Their findings suggest that the size of modern mammals and birds can be well explained by this model, but the reason why even the smallest dinosaurs remained relatively large, akin to pigeon-sized, remains elusive. These ancient feathered dinosaurs, known as microraptors, existed during the early Cretaceous period, around 145 million years ago. The study indicates that these creatures were at least 200 times heavier than the world's smallest modern bird, the Bee-ele (Mellisuga helenae), which weighs just 1.75 grams, and smaller than the world's tiniest modern mammal, the Etruscan Shrew (Suncus etruscus), which weighs about 1.8 grams. The researchers hypothesize that the competition with small mammals for resources was the primary reason why dinosaurs never occupied this ecological niche. According to the model, the most likely dinosaur weight was three kilograms. While the model works well for modern mammals, birds, and even reptiles like turtles, it falls short when applied to today's lizards and flightless birds in island environments due to ecological constraints. The optimal modal size, or the most common size in a group, for dinosaurs, the model predicts, would be around three kilograms, while the actual observed modal size among dinosaurs is roughly 180 kilograms. This discrepancy may be due to the nature of fossil discoveries, as larger fossils are more likely to be found. However, the absence of mini-dinosaur bones is striking. Other tiny fossil bones have been discovered. Today, small animals dominate all habitats on the planet. Understanding the origins of the current biodiversity requires understanding why tiny dinosaurs seem to be missing. While it is theoretically possible that smaller dinosaur fossils have simply not been found, the researchers believe this scenario is unlikely. Fossil sites known to contain dinosaurs often also contain smaller creatures like lizards and amphibians. If mini-dinosaurs had existed, they would have eventually made an appearance somewhere.",
  "summary": "Sie galten als die Herrscher der Erde – doch die Herrschaft der Dinosaurier hatte eine überraschende Grenze: nach unten, sie waren nie richtig klein. Einer Studie zufolge lag das an der Konkurrenz.",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 2,
    "also_reported_by": [
      {
        "outlet": "Handelsblatt",
        "title": "Clemens Fuest: Why a progressive value-added tax helps Germany",
        "url": "https://urgent.news/2026/08/05/clemens-fuest-warum-eine-progressive-mehrwertsteuer-deutschland-hilft",
        "published": "2026-08-05T06:38:30.000Z"
      }
    ]
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}