Prehistoric Earth was a land of giants.
When the dinosaurs came on the scene during the Mesozoic Era, the Earth saw some of the biggest creatures to have ever lived.
Archaeological evidence suggests that the largest of them may have been as big as a large Boeing 737 airplane and were heavier than 12 elephants combined.
Expectedly, when most people think of dinosaurs, their mind conjures images of massive beasts the size of buildings.
But dinosaurs came in all shapes and sizes.
You’ll be shocked to discover that the smallest dinosaurs were about the same size as a chicken or small bird.
These tiny dinosaurs lived alongside massive beasts like the Tyrannosaurus, Triceratops, and Dreadnoughtus across different periods of geologic history.
In this article, we’ll list 15 of the smallest dinosaur species ever discovered and explain some of the fascinating facts about them.
15. Magyarosaurus
| Name | Magyarosaurus |
| Name Meaning | Hungarian Lizard |
| Pronunciation | MAH-dyahr-oh-SAWR-us |
| Era | Mesozoic – Late Cretaceous |
| Classification | Dinosauria, Saurischia & Sauropoda |
| Diet | Herbivorous |
| Height | 3–4 meters (10–13 feet) |
| Length | 6–7 meters (20–23 feet) |
| Weight | 750–1,000 kg (1,650–2,200 lbs) |
| Location | Romania |
The sauropods were the biggest of all the dinosaurs.
Some of these long-necked beasts reached lengths of up to 98 feet (30 meters) long and weighed as much as 50 tons.
But a few of them, like the Magyarosaurus, were smaller than usual.
Although this dinosaur is bigger than most of the other dinosaurs on this list, it deserves a spot on the smallest dinosaur species because of its small size compared to its relatives.
This dwarf dinosaur was just six meters (20 feet) long and about 750–1,000 kilograms (1,650–2,200 pounds) in body mass.
It lived on an Island in Romania known as Hateg Island. Many animal species found on this island exhibited insular dwarfism.
This is a phenomenon in which isolated animal species grow into smaller sizes compared to their relatives due to limited food supply and a lack of large predators.
This explains why Magyarosaurus evolved into a smaller size compared to their ancestors.
14. Aquilops
| Name | Aquilops |
| Name Meaning | Eagle Face |
| Pronunciation | AH-kwih-lops |
| Era | Mesozoic – Late Cretaceous |
| Classification | Dinosauria, Ornithischia & Ceratopsia |
| Diet | Herbivorous |
| Height | 0.3 meters (1 foot) |
| Length | 60 centimeters (23 inches) |
| Weight | 1.5kg (3.3 lbs) |
| Location | USA (North America) |
Aquilops is a ceratopsian dinosaur, which means it is related to some of the earth’s biggest armored herbivores like the iconic Triceratops.
Members of this family are known for their fierce look, characterized by large frills and multiple horns.
One species, the Kosmoceratops, had at least 15 horns on its face.
Strangely, the Aquilops didn’t have any of these elaborate features, and it wasn’t large either.
With an estimated weight of just three pounds, Aquilops was up to 4,000 times smaller than its three-horned cousin, the Triceratops.
It was about two feet long, which means it would have been roughly the size of a small cat.
The name Aquilops means “eagle face” and is a reference to the curvature of the dinosaur’s beak, which resembles that of an eagle.
Despite this obvious raptorial feature, this dinosaur was not a meat-eater.
Like other ceratopsians, it fed on plant materials.
Aquilops lived in North America during the Early Cretaceous, about 109 million to 104 million years ago.
That was several million years before the Late Cretaceous species like the Triceratops came on the scene.
This means this dinosaur was one of the first ceratopsians to migrate to the North American continent from Asia.
13. Wannanosaurus
| Name | Wannanosaurus |
| Name Meaning | Wannan Lizard |
| Pronunciation | Wah-nah-noh-SAWR-us |
| Era | Mesozoic – Late Cretaceous |
| Classification | Dinosauria, Ornithischia & Thyreophora |
| Diet | Herbivorous |
| Height | 0.6 meters (24 inches) |
| Length | 60 centimeters (2 feet) |
| Weight | 4.5 kg (10 pounds) |
| Location | China (Asia) |
Wannanosaurus was a genus of pachycephalosaurian dinosaurs that lived in Asia towards the end of the Cretaceous Period about 70 million years ago.
When scientists discovered the bones of this 60 centimeters (two feet) long dinosaur, they were so small that there were speculations that the bones belonged to a juvenile dinosaur.
However, the skull bones showed signs that they were fused, an indication that the bones belonged to an adult dinosaur.
Wannanosaurus is related to Pachycephalosaurus and other thick-headed dinosaurs known for their domed skulls that looked like bicycle helmets.
But unlike its younger relatives, the skull of the Wannanosaurus was not domed.
This led to the conclusion that this dinosaur was a primitive member of the pachycephalosaurian group.
Due to the limited fossil remains of this dinosaur, not a lot is known about its actual appearance and how it lived.
12. Hesperonychus
| Name | Hesperonychus |
| Name Meaning | Western Claw |
| Pronunciation | Hes-per-oh-NY-kus |
| Era | Mesozoic – Late Cretaceous |
| Classification | Dinosauria, Saurischia & Theropoda |
| Diet | Carnivorous |
| Height | 0.5 meters (1.6 feet) |
| Length | 1 meter (3.3 feet) |
| Weight | 1.5 – 2 kilograms (3.3–4.4 lbs) |
| Location | Alberta, Canada (North America) |
The Hesperonychus was one of the smallest carnivorous non-avian dinosaurs from North America.
A relative of the Velociraptor, this cat-sized predator lived in Alberta, Canada, during the Late Cretaceous Period about 76.5 million years ago.
Although it is only known from partial remains, experts have estimated this dinosaur’s length to be about 1 meter (3.3 feet) at most.
It probably weighed about 1.5 to 2 kilograms (3.3–4.4 pounds).
Although small by dinosaur standards, the Hesperonychus was still big enough to prey on small mammals and reptiles in its ecosystems.
Most of the North American mammals alive during the Late Cretaceous were small and were mostly herbivores or insectivores.
Hesperonychus occupied an interesting ecological niche, preying on these small mammals.
The dinosaur’s name translates as “western claw,” a reference to the long sharp claws it used to subdue prey.
Like other dromaeosaurids, the Hesperonychus probably had wings and feathers, and it may have been capable of flying (or at least gliding from tree to tree).
11. Eodromaeus
| Name | Eodromaeus |
| Name Meaning | Dawn Runner |
| Pronunciation | ee-o-DROH-mee-us |
| Era | Mesozoic – Late Triassic |
| Classification | Dinosauria & Saurischia & Theropoda |
| Diet | Carnivorous |
| Height | 0.5–1 meter (1.6–3.3 feet) |
| Length | 1.2 meters (3.9 feet) |
| Weight | 4.5 to 6.8 kg (9.9 to 15.0 lbs) |
| Location | Argentina (South America) |
Eodromaeus was the ancestor of giant meat-eating theropods like the Tyrannosaurus but was significantly smaller in size.
It lived in Argentina about 230 million years ago, which means it was among the earliest theropod dinosaurs to ever evolve.
Eodromaeus had an estimated length of just 1.2 meters (3.9 feet) and weighed between 4.5 and 6.8 kilograms (9.9 to 15.0 pounds). Although lightly built, this dinosaur shows features of a very efficient predator.
The dinosaur’s mouth was filled with several knife-shaped teeth, and it also had sharp-clawed hands.
Eodromaeus was an active predator capable of chasing down and killing small prey animals.
10. Bambiraptor
| Name | Bambiraptor |
| Name Meaning | Bambi Thief |
| Pronunciation | Bam-bee-RAP-tor |
| Era | Mesozoic – Late Cretaceous |
| Classification | Dinosauria, Saurischia & Theropoda |
| Diet | Carnivorous |
| Height | 0.4 meters (1.3 feet) |
| Length | 1 meter (3.3 feet) |
| Weight | 2 kilograms (4.4 lbs) |
| Location | North America (USA) |
The Bambiraptor was named after Bambi, a popular cartoon character from Disney’s animated drama film of the same title.
The name was probably inspired by the fact that the dinosaur’s bone was found by a 14-year-old.
Despite the cute name, the 72 million-year-old Bambiraptor was anything but cute and gentle.
It was a ferocious dinosaur with long, slashing claws that were quite effective in taking down prey.
They may have hunted in packs as well, making them even more dangerous.
You probably wouldn’t be scared of a single Bambiraptor.
The dinosaur was just one meter (3.2 feet) long and weighed just two kilograms (4.4 pounds) on average.
In addition to the impressive size of this dinosaur, the Bambiraptor is popular in the world of paleontology because of the completeness of the fossil.
It is often referred to as the “Rosetta Stone” of raptors because of its role in the understanding of the evolution of dromaeosaurid dinosaurs.
9. Guaibasaurus
| Name | Guaibasaurus |
| Name Meaning | Named after the Guaíba Formation, where it was discovered |
| Pronunciation | Gwah-ee-bah-SAWR-us |
| Era | Mesozoic – Late Triassic |
| Classification | Dinosauria, Saurischia & Sauropodomorpha |
| Diet | Carnivorous |
| Height | Around 1 meter (3.3 feet) |
| Length | 2-3 meters (6.6 to 10 feet) |
| Weight | 10 to 35 kg (22 to 77 lbs) |
| Location | Brazil (South America) |
The first dinosaurs appeared during the Triassic Period and were significantly smaller compared to the massive giants we’re now familiar with.
The Guaibasaurus is one such basal dinosaur.
Estimates of this dinosaur’s length range between two and three meters (6.6 to 10 feet) and a mass of about 10 to 35 kilograms (22 to 77 pounds).
Guaibasaurus lived in South America, specifically in the southern region of present-day Brazil.
Although it is typically considered a sauropod dinosaur, some experts think the Guaibasaurus was a theropod.
The lack of skull fossils for this dinosaur makes it difficult to fully describe or characterize it.
8. Eoraptor
| Name | Eoraptor |
| Name Meaning | Dawn Thief |
| Pronunciation | EE-oh-RAP-tor |
| Era | Mesozoic – Late Triassic |
| Classification | Dinosauria, Saurischia & Theropoda |
| Diet | Likely omnivorous or carnivorous |
| Height | Around 0.5 meters (1.5 feet) |
| Length | 1 meter (3 feet) |
| Weight | 5-10 kilograms (11-22 pounds) |
| Location | Argentina (South America) |
Eoraptor was a lightly-built sauropod dinosaur that lived 231 to 228 million years ago.
This means it was one of the earliest known sauropods.
Eoraptor was about 1.5 feet tall at the hips and had an estimated length of about three feet.
The dinosaur’s name translates as “dawn plunderer,” which is a reference to its primitive nature (at the dawn of dinosaur evolution) and its presumed nature as carnivorous.
Research has shown that the Eoraptor was not a carnivore. It was an omnivore that ate plant materials but was also capable of hunting small prey.
7. Mei long
| Name | Mei long |
| Name Meaning | Sleeping Dragon |
| Pronunciation | May-long |
| Era | Mesozoic – Late Cretaceous |
| Classification | Dinosauria, Saurischia & Theropoda |
| Diet | Carnivorous |
| Height | 0.5 meters (1.6 feet) |
| Length | 53 centimeters (21 inches) long (for a juvenile) |
| Weight | 1 kilogram (2.2 pounds) |
| Location | China (Asia) |
Troodontids are a group of bird-like dinosaurs that were quite abundant during the Cretaceous Period.
They were agile predators often described as intelligent dinosaurs.
Mei long was a member of this dinosaur group that lived in China during the Early Cretaceous.
It is known from only one juvenile fossil found in well-preserved condition.
The specimen was about 53 centimeters (21 inches) long, and adult Mei would have been about the same size as a duck.
Mei long is so popular because it was preserved in exquisite three-dimensional detail.
The fossil’s sleep-like pose is the reason for its name, which translates as “sleeping dragon.”
6. Guanlong
| Name | Guanlong |
| Name Meaning | Crown Dragon |
| Pronunciation | Gwan-long |
| Era | Mesozoic – Late Jurassic |
| Classification | Dinosauria, Theropoda, Tyrannosauroidea |
| Diet | Carnivorous |
| Height | 1.5 meters (5 feet) |
| Length | 3 meters (10 feet) |
| Weight | 125 kg (276 lb) |
| Location | China (Asia) |
Guanlong is a relative of the Tyrannosaurus that lived in Asia during the Late Jurassic period.
However, this dinosaur looked quite different from its North American cousin. It was about 3 to 3.5 meters (9.8–11.5 feet) long and had an estimated mass of about 125 kilograms (276 pounds).
This means it was about four times smaller than the T-rex.
Another unique feature of this dinosaur was its delicate head crest which ran along its snout from the nostril to the eye sockets.
The crest was air-filled and was not useful as a weapon.
Like a typical tyrannosaur, Gualong hunted smaller dinosaurs, other reptiles, and mammals in its ecosystem.
5. Stenonychosaurus
| Name | Stenonychosaurus |
| Name Meaning | Narrow Claw Lizard |
| Pronunciation | Sten-oh-NY-koh-SAWR-us |
| Era | Mesozoic – Late Cretaceous |
| Classification | Dinosauria, Saurischia & Theropoda |
| Diet | Carnivorous |
| Height | 0.7 meters (2.3 feet) |
| Length | 2.5 meters (8.2 feet) |
| Weight | 35 kilograms (77 lbs) |
| Location | Canada, USA (North America) |
Stenonychosaurus was a small theropod dinosaur about the size of a large turkey.
It measured roughly 2.5 meters (8.2 feet) in length and weighed about 35 kilograms (77 pounds).
It was a troodontids dinosaur that lived in North America during the Late Cretaceous Period.
Scientists are not exactly sure of this dinosaur’s diet.
While the sickle-shaped claw of the Stenonychosaurus suggests that it was an active predator, the dinosaur’s dentition is more similar to that of an omnivore.
The most distinct feature of this dinosaur was its exceptionally large brain.
This has been interpreted as a sign of advanced intelligence compared to contemporary dinosaurs.
4. Microraptor
| Name | Microraptor |
| Name Meaning | Small Thief or Tiny Predator |
| Pronunciation | My-kroh-rap-tor |
| Era | Mesozoic – Early Cretaceous |
| Classification | Dinosauria, Saurischia & Theropoda |
| Diet | Carnivorous (potentially scavenging) or piscivorous |
| Height | 0.4 meters (1.3 feet) |
| Length | 80centimeters (2.6 feet) |
| Weight | 1.25–1.88 kilograms (2.8–4.1 lbs) |
| Location | China (Asia) |
Microraptors were bird-like dinosaurs that lived in China during the Early Cretaceous Period (between 125 and 120 million years ago).
It belonged to a family of feathered dinosaurs known as the dromaeosaurids, meaning it was a close relative of raptors like the Velociraptor and Utahraptor.
While these close relatives of the Microraptor were relatively large, the Microraptor was around the same size as modern birds.
The largest of them was probably about 80 centimeters (2.6 feet) long and weighed between 1.25–1.88 kilograms (2.8–4.1 lbs).
The Microraptor is an interesting dinosaur that is considered one of the first non-avian dinosaurs with well-preserved feather and wing impressions.
The feathers of this dinosaur were so well-preserved that scientists have been able to identify fossilized pigment cells on them.
An analysis of these cells suggests that the Microraptor had a black, glossy coloration similar to those of modern birds like crows.
Since not all dinosaurs with feathers could fly, it isn’t clear if the Microraptor was capable of powered flight or if it was simply a glider.
But with flight feathers on both the forelimbs and hindlimbs of this dinosaur, it was most likely capable of true flight.
Despite its small size, the Microraptor was probably an active predator in both terrestrial habitats.
With more than 300 fossils found so far, the Microraptor is one of the most well-known dromaeosaurid dinosaurs from the Cretaceous ecosystem.
3. Compsognathus
| Name | Compsognathus |
| Name Meaning | Elegant Jaw |
| Pronunciation | Kom-sohg-NAY-thus |
| Era | Mesozoic – Late Jurassic |
| Classification | Dinosauria, Saurischia & Theropoda |
| Diet | Carnivorous |
| Height | 20 centimeters (7.9 inches) |
| Length | 89 centimeters (35 inches) |
| Weight | 100–250 kg (220–550 lbs) |
| Location | 0.32–0.58 kg (0.71–1.3 lbs) |
Compsognathus was a genus of small theropod dinosaur that was alive during the Late Jurassic Period about 150 million years ago.
This small dinosaur, which lived in parts of Germany and France, was about the same size as a Turkey.
Until the discovery of smaller non-avian dinosaurs like the Microraptor in the 1990s, the Compsognathus was considered the smallest dinosaur ever found.
Although it was discovered early in the 19th century, paleontologists didn’t positively identify Compsognathus as a dinosaur immediately.
Instead, it was treated as a strange-looking lizard for several decades after its discovery.
Later it was considered a relative of the avian dinosaur Archaeopteryx instead of a true theropod.
Compsognathus measured just 89 centimeters (35 inches) in length, stood at a height of about 20 centimeters (7.9 inches), and weighed about one pound.
Yet, scientists believe it was an apex predator in its ecosystem.
Compsognathus lived alongside small reptiles, pterosaurs, and prehistoric fish.
It was an agile runner with small forelimbs and two clawed digits that may have helped take down prey.
This dinosaur may have fed by swallowing its prey whole.
2. Mahakala
| Name | Mahakala |
| Name Meaning | Named after the Tibetan Buddhist god of protection |
| Pronunciation | Ma-ha-Ka-la |
| Era | Mesozoic – Late Cretaceous |
| Classification | Dinosauria, Saurischia & Theropoda |
| Diet | Carnivorous |
| Height | 1.5 meters (5 feet) |
| Length | 50–70 centimeters (20–28 inches) |
| Weight | 400–700 grams (14–25 oz) |
| Location | Mongolia (Asia) |
Named after one of the Tibetan Buddhist gods of protection, Mahakala was a diminutive dinosaur that lived in Mongolia during the Late Cretaceous Period.
It was a dromaeosaurid dinosaur, meaning it is considered a raptor, but it was quite small compared to many of its relatives.
Experts think this dinosaur was one of the most primitive dromaeosaurids ever found.
Mahakala measured just 50–70 centimeters (20–28 inches) in length and weighed about 400–700 grams (14–25 oz).
This weird little raptor may have lived a semiaquatic lifestyle, but there’s no evidence for this.
If this is true, then this dinosaur most likely spent significant time in or near water bodies, and its forelimbs may have been modified to form flippers.
1. Epidexipteryx
| Name | Epidexipteryx |
| Name Meaning | Display Feather |
| Pronunciation | ep-ih-DEX-ip-TER-iks |
| Era | Mesozoic – Late Jurassic |
| Classification | Dinosauria, Saurischia & Theropoda |
| Diet | Likely omnivorous, possibly insectivorous |
| Height | 25 centimeters (10 inches) |
| Length | 44.5 cm (17.5 inches) |
| Weight | 164 grams (5.8 ounces) |
| Location | China (specifically, Daohugou Beds) |
Epidexipteryx was a small theropod dinosaur that lived in China during the Middle to Late Jurassic Period (between 168 and 160 million years ago).
It measured just 25 centimeters (10 inches) in length and weighed just 164 grams (5.7 ounces).
Only one fossil of this dinosaur has been found so far, but the fossil is so well-preserved that scientists have been able to determine that the Epidexipteryx had colorful tail feathers similar to those of peacocks.
The dinosaur would be 44.5 centimeters or 17.5 inches long if you add the length of its tail feathers.
Male Epidexipteryx probably used their ornate feathers to attract females for mating.
Given its age, the Epidexipteryx is the oldest dinosaur with ornamental feathers known so far.
Epidexipteryx is closely related to modern birds. It is a maniraptoran, a family of dinosaurs believed to be direct ancestors of birds.
Despite this close relationship to birds, Epidexipteryx lacked wings, so it was probably incapable of powered flight.
Sources
- https://en.wikipedia.org/wiki/Epidexipteryx
- https://www.britannica.com/animal/Compsognathus
- https://www.cs.mcgill.ca/~rwest/wikispeedia/wpcd/wp/m/Microraptor.htm
- https://en.wikipedia.org/wiki/Guanlong
- https://www.discovermagazine.com/planet-earth/meet-mei-long-the-sleeping-dragon
- https://en.wikipedia.org/wiki/Guaibasaurus
- https://kids.britannica.com/students/article/Eoraptor/390681
- https://samnoblemuseum.ou.edu/collections-and-research/vertebrate-paleontology/discovering-aquilops-americanus/ https://en.wikipedia.org/wiki/Wannanosaurus
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