What Is The Weakest Dinosaur?

There is plenty written about the biggest, scariest and strongest dinosaurs, these are the dinosaurs that capture the imagination. However there were over 1000 dinosaurs currently known to science, and some of those were the weakest dinosaurs. We take a look at which dinosaurs could be considered the weakest dinosaurs below.

Smaller, less well protected dinosaurs like ceratopsian – microceratus or Sauropod – Ohmdenosaurus could be considered the weakest dinosaurs in their families. Dinosaurs were well adapted to their environments and all strong in individual ways. However, there were weaknesses across all dinosaur genus and families.

As it is basically impossible to really judge which was the weakest dinosaur was the weakest ever, not least because we are basing all assumptions from fossils, we have a list and a table of dinosaurs that MAY have been weaker than other dinosaurs in their families.

we take a look at the Main groups of dinosaurs and give some ideas on the weakest dinosaur in that group. You can let us know if you agree or disagree, but neither can prove the other right or wrong! We just have to take educated guesses!


Table 1: Candidates for Weakest Dinosaur

Dinosaur NameDinosaur FamilyStrengthsWeaknessesSizePeriod Lived
MicroceratusCeratopsianSharp beakSize, speed, no armor, protection2 feet (60 Cm)Late Cretaceous. 90 million
CompsognathusCarnivore / theropodTeeth, speed, possibly pack huntingsize, weight, lived in isolated area ( no competition) 2 feet+ (70 cm) Late Jurassic 158 million Years ago
OhmdenosaurusSauropodlack of predatorsSize for a sauropod, short 13 feet (4 metres)Middle Jurassic
Tethyshadros HadrosaurPossible speedVery small for a hadrosaur15 feet (4.5 metres) Late Cretaceous
LiaoningosaurusAnkylosaurAquatic, sharp teeth and claws, some armorSmall in size, probably not great on land30 cm 1 foot longEarly Cretaceous

Are The Smallest the Weakest

In animal kingdom it does hold true that ight is right and size does matter. However there are exceptions to every rule. Think of a virus, easy to do in recent times, and what they lack in size they make up for in numbers.

So while on their own there are plenty of weak dinosaurs if size is the only factor there are many other factors to take into consideration. We explore these in the article below and the factors in the list directly underneath.

Factors to determine Dinosaur weakness

  • Armour: How well armored was the dinosaur, did it have spikes or Osteoderms to help prevent attack
  • Speed: Could the dinosaur escape if needed using speed to outrun predators
  • Pack / Groups: Did the dinosaur live in herds or with others to help protect it.
  • Size: Was the dinosaur large enough to discourage predators or fight back if attacked.
  • Weight: was the dinosaur heavy nought to be powerful enough to fight back .

What were the Weakest Dinosaurs?

We look at five dinosaur genus/families below to see which could be considered the weakest in each individual families. these families are:

  • Ceratopsian – Horned Face Dinosaurs
  • Hadrosaur – Duck Billed Herbivores
  • Therapod – Carnivores the meat eating predators.
  • Sauropod – the Long Necked Dinosaurs
  • Ankylosaurs – the Armoured Dinosaurs

What was the Weakest Ceratopsian: Microceratus

There are a few contenders for what was likely the weakest of the horned face dinosaurs. Protoceratops, gryphoceratops and the dinosaur we settled on for the weakest ceratopsian the Microceratus.

it is the smallest of the ceratopsians, of a similar size but likely slower than Aquilops  which while not the only factor it a large part of judging what would make it weak. it grew to about 60 cms long, that’s only about 2 feet. it would have weighed about 5 kg ( 10 lbs) it lived in the late cretaceous period about 90 million years ago in what is not Asia.

What makes Microceratus the weakest Ceratopsian dinosaur?

It was a member of the ceratopsian family which means horned face, however it had no horns to use to defend itself or act as a warning. In fact despite a small frill on its neck which would have offered little protection and a sharp beak, although like the rest of the dinosaur also small, it did not look like its bigger descendants.

Horned face dinosaurs are known for large frills, spikes, and horns and microceratus has none of these ( well a small frill) it did walk on two legs which may have made it more agile that larger ceratopsians like triceratops, but we are not sure if this would have been much of an advantage in comparison


What is the weakest dinosaur

The Microceratus has not fared well in its interactions with people, both in reality and in media as well. We have listed the problems Microceratus has faced even 90 million years after extinction.

  • It was too weak to hold on to its name! It was originally called Microceratops (small horned face) but this name had already been given to a species of wasp. it was also, mostly reclassified as graciliceratops, and only the type specimen has the name Microceratus.
  • Its first appearance in movies, Jurassic World Dominion, was as a sandwich filling for a Mad Max type scene where it was used to be skewered and spit roasted like a BBQ pig. It did appear being petted in a much less traumatic scene by a young Charlotte Lockwood as some balance to being eaten.

When compared to others in its family group it is definitely a contender for the weakest dinosaur.

What was the Weakest Hadrosaur: Tethyshadros

Tethyshadros has been discovered in two sizes in italy. it was small for a hadrosaur, which traditionally would have relied on size to dissuade hungry predators. it lived about 8- million years ago.

What makes Tethyshadros the Weakest Hadrosaur Dinosaur?

The main defenses a hadrosaur would have possessed are size, speed and power. While the tethyshadros would have been relatively fast compared to its larger cousins it was certainly no where near as large or powerful.

it would grow to about 15 feet long and weigh about 700 -1200 lbs ( 350 -580 kg) while still large, it would not have been large enough to put off even a medium predatory dinosaur from having a bite.

weakest hadrosaur dinsaour

if they did have a bite, then tethyshadros had nothing much to fight back with. A duck billed beak was not going to do much damage, and it even lacked the thumb spikes of iguanodon to try to stop a predator. running would have been its only option.

We would put these species of dinosaurs on any list of weakest dinosaurs due to their lack of defense, armour, or relative speed, or slikes. they were like the supermarkets of the Jurassic and Cretaceous for carnivores. A meal ready to be taken.

What was the Weakest Carnivore: Compsognathus

It may be a surprise to see a carnivorous dinosaur in an article about the weakest dinosaurs but not all meat eating dinosaurs were the size of the huge many toothed dinosaurs like T-Rex, Spinosaurus, giganotosaurus and others.

For carnivorous, at least for this section we will discuss the bird like dinosaurs further down, we suggest the compsognathus as the weakest of the carnivores. However it comes with a proviso. Carnivores, by nature, could not really be call the weakest dinosaurs. if they had any serious weakness they simply would have gone extinct. When you have to catch and kill your food weakness is not an option.

What was the weakest dinosaur
The tiny Compy

What makes Compsognathus the weakest Carnivore dinosaur?

Compared to most, and more famous, carnivores though Compsognathus was small and slender. this was an actual advantage to it for its diet and location.

it lived in an area with few predators, and ironically may have been the apex predator of its sarea, however next to almost any other mating eating animal it doesn’t fare well.

it was about 2 feet (70 cms) long and weigh up to 1.5 lbs ( 600g) ( though it depends which fossils you look at as some vary in size) and you can read more about it in the link here and below. and although suggested to live in packs there is no direct evidence for this. if it is proved it did live in groups it would not be classed as the weakest dinosaur as there is strength in numbers!

What was the Weakest Sauropod Dinosaur? Ohmdenosaurus

Ohmdenosaurus was a long necked dinosaur. These are known as sauropods. Now usually, and the best known, are huge dinosaurs that can grow to over 100 feet and over 100,000 lbs, they could be so strong they could push down huge trees to get to the leaves. In fact one of these was so large it was called Dreadnoughtus, a name that means “fears nothing”

However there were smaller, lighter and less powerful sauropods as well, for each building size dinosaur there were smaller horse sized as well. One of these, and possibly the smallest was called Ohmdenosaurus.

How big were sauropod babies, brachiosaurus, argentinosaurus, barosaurus, apatosaurus, dreadnoughtus
Ohmdenosaurus small

What makes Ohmdenosaurus the Weakest Sauropod Dinosaur?

Despite being the largest dinosaur in this list it was tiny compared to almost any other sauropod dinosaur known. it could grown to about 13 feet long as a maximum and would have weighed an estimated 500-800 kg ( 1100 – 2000 lbs) which again is not small, but it certainly isnt the 100,000 lbs some of its descendants could weigh.

this means it would have been vulnerable to medium to large carnivores, and with so little weight swinging its tail at them would not have been much of a deterrent. This is why we have this as the weakest dinosaur in the sauropod family.

What was the weakest Ankylosaur? Liaoningosaurus

There is a small recently discovered ankylosaur family member that may have been a little more blood thirsty than all of its family members. Now even if an omnivore ( the first ever ankylosaur to be thought as such) it had some drawbacks that made it weaker than other members of its family. this Ankylosaur was called Liaoningosaurus.

What made Liaoningosaurus a weak ankylosaur?

Liaoningosaurus fossils were discovered with a belly full of fish, and they had sharper needle like teeth that would have been useful when catching fish to eat. However most if not all ankylosaur dinosaurs were thought to be herbivorous dinosaurs so how does a carnivore style lifestyle make this dinosaur weak.

Liaoningosaurus weakest dinosaur ankylosaur

the simple answer is it doesn’t. What makes Liaoningosaurus a weaker ankylosaur member is its size. the fossils were only 30 cm in length, that is just one foot long. it was a tiny member of the family. ( though it has been suggest it may have been a junior of another species this is not confirmed) If it is then we will take a longer look at Minmi as a potential replacement for the weakest dinosaur in the ankylosaur family.


We have looked at 5 of the most common dinosaur family / genus and put forward some ideas on what would make these dinosaurs the weakest in those groups. We came up with the following as the weakest dinosaurs.

  • Weakest Carnivore dinosaur: Compsognathus
  • Weakest Hadrosaur Dinosaur: Tethyshadros
  • Weakest Ankylosaur Dinosaur: Liaoningosaurus
  • Weakest Sauropod Dinosaur: Ohmdenosaurus
  • Weakest Ceratopsian Dinosaur: Microceratus

Out of 1000 plus known dinosaurs it really is beyond the realms of reality to suggest the weakest of all the dinosaurs, they all managed to survive, evolve and thrive in their environments much better than we would manage. So it is not possible to call any of them the weakest…….



its the Microceratus, any day of the week, it’s the Microceratus.





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