Dinosaurs are often associated with immense creatures, but their diversity included a surprising range of sizes. This leads to curiosity about the smallest dinosaurs, revealing not only tiny extinct animals but also their enduring legacy in the modern world.
Identifying the Smallest Non-Avian Dinosaur
The public typically envisions non-avian species when thinking of dinosaurs. For many years, Compsognathus was widely recognized as the smallest non-avian dinosaur. This agile, bipedal carnivore lived during the Late Jurassic period, approximately 150 million years ago, in what is now Europe. Fossils of Compsognathus have been discovered in limestone deposits in Germany and France.
Compsognathus longipes, the single recognized species, was roughly the size of a chicken or turkey, measuring about 2 to 3 feet (0.7 to 1 meter) in length. Its estimated weight was a few kilograms, 4.4 to 6.5 pounds (2 to 3 kg). This diminutive predator had a slender build, with a small, pointed head, sharp teeth, and hollow bones. Fossilized stomach contents have revealed it preyed on small animals, including lizards and insects.
More recently, discoveries have introduced even smaller contenders among non-avian dinosaurs. Anchiornis huxleyi is a feathered paravian dinosaur from the Late Jurassic period, found in China. It was about the size of a crow, with estimates placing its length at approximately 13 inches (34 cm) and its weight at just 3.9 ounces (110 g). While its classification as strictly non-avian is sometimes debated due to its close ties to birds, Anchiornis represents a significant find.
The Smallest Living Dinosaurs
Scientific understanding includes birds as living dinosaurs, direct descendants of avian dinosaurs. This evolutionary connection means that the answer to the “smallest dinosaur” question ultimately leads to the avian world. Among the thousands of bird species, one stands out for its remarkably tiny size.
The Bee Hummingbird (Mellisuga helenae), native to Cuba, holds the title of the smallest known living dinosaur. This minuscule creature is hardly larger than a bee. Females of the species are slightly larger, measuring about 2.4 inches (6.1 cm) long and weighing approximately 0.092 ounces (2.6 g). Males are even smaller, with an average length of 2.1 inches (5.5 cm) and a weight of about 0.069 ounces (1.95 g).
The Bee Hummingbird’s tiny stature is accompanied by extraordinary adaptations. It possesses an exceptionally high metabolism, requiring frequent feeding on flower nectar. Its wings beat at an astonishing rate, sometimes between 80 and 200 times per second, allowing it to hover in mid-air to access nectar. This rapid wing movement also produces a distinct humming sound.
Why Pinpointing the Smallest is Complex
Determining the absolute smallest dinosaur is complex due to several factors. One challenge lies in the incomplete nature of the fossil record. Most dinosaurs are known only from partial remains, making precise size estimations difficult. Smaller, more delicate bones are less likely to be preserved, meaning many small species may never be discovered or their full adult size underestimated from juvenile specimens.
The definition of “dinosaur” itself adds complexity. Scientific classification includes both extinct non-avian dinosaurs and their living descendants, birds. This distinction is important, as the smallest non-avian dinosaur is considerably larger than the smallest living bird, the Bee Hummingbird. The answer depends on whether the question refers to extinct forms or includes modern species.
Identifying adult specimens from small species can be challenging. Paleontologists must differentiate between a small-bodied adult dinosaur and a juvenile of a larger species. The criteria for “smallest” can also vary, whether it refers to length, height, or weight, potentially leading to different species holding the title depending on the measurement used.