Fun Alvarezsaurus Facts For Kids

Moumita Dutta
Feb 29, 2024 By Moumita Dutta
Originally Published on Nov 18, 2021
Edited by Luca Demetriou
Fact-checked by Kidadl Team
Alvarezsaurus facts are interesting.
Age: 3-18
Read time: 6.9 Min

Alvarezsaurus was a genus of small carnivorous dinosaurs that existed during the Late Cretaceous age. The Alvarezsaurus was a small dinosaur. However, it was still a larger one compared to the other members of the group. This dinosaur is believed to be the ancestor of modern-day birds. They were recovered from the Argentine range of the Formation. This dinosaur group was the first group of their family that was discovered. Later many other groups were discovered from different parts of the that had features similar to an Alvarezsauridae.

Therefore the family name was a replica of the name of this genus. In spite of that, now, when many Alvarezsaurids have been discovered throughout the world, the type genus of the family, the Alvaresaurus, has become the least understood and most incomplete dinosaur currently. Rather its closely related genera like Shuvuuia and Mononykus are better-known members of the family currently than them. Another name of the Alvarezsaurus is also known to be Alvarezsaur. To know more about this dinosaur, keep on reading these amazing facts.

For similar content, check out Orolotitan facts and Aralosaurus facts too.

Alvarezsaurus Interesting Facts

How do you pronounce 'Alvarezsaurus'?

The Alvarezsaurus formed a major part of the Alvarezsauridae family along with other genera like Shuvuuia and Mononykus. The name Alvarezsaurus is pronounced as Al-vah-rez-sore-us in English. Their name was given by Jose Bonaparte, and it translates to Alvarez's Lizard.

What type of dinosaur was an Alvarezsaurus?

The Alvarezsaurus was a type of bipedal theropod dinosaur that lived during the Late Cretaceous period on earth. It was considered to be one of the basal dinosaurs of the Alvarezsauridae family since they were discovered first in their family. The fossils of A. calvoi were discovered in the late 20th century by Jose Bonaparte in Argentina.

In which geological period did Alvarezsaurus roam the earth?

The Alvarezsaurus were found on earth during the Late Cretaceous period. They came into existence around 89 million years ago and lasted till 85 million years ago.

When did the Alvarezsaurus become extinct?

The Alvarezsaurus became extinct when the Cretaceous stage was still ongoing. The dinosaur became extinct 85 million years ago, which was approximately around 20 million years before the cretaceous epoch ended.

Where did Alvarezsaurus live?

The Alvarezsaurus fossil was discovered from Bajo de la Carpa Formation in Argentina. It is believed that they lived in Patagonia, a supercontinent including South America and Africa.

What was the Alvarezsaurus' habitat?

The Alvarezsaurus preferred to live in terrestrial habitats. Their diet possibly included local insects and ants. Therefore living near the nesting areas of insects helped them to gather food easily.

Who did Alvarezsaurus live with?

The Alvarezsaurus was a small dinosaur but whether it lived in groups or in solitude is unknown.

How long did an Alvarezsaurus live?

The Alvarezsaurus was a genus of the Late Cretaceous period. The entire genus lasted for about four million years on earth. The existence of such dinosaurs dates back to 85-89 million years ago.

How did they reproduce?

Like every other dinosaur, the Alvarezsaurus also reproduced by laying eggs. The reproduction method was oviparous. After mating, females laid eggs, and juveniles emerged from the eggs. The rest of the information about their breeding process is missing.

Alvarezsaurus Fun Facts

What did Alvarezsaurus look like?

The Alvarezsaurus was a small carnivorous dinosaur with a long tail; they were found during the Late Cretaceous period. The structure of the leg of this dinosaur indicates that it might have been a fast runner. The caudal vertebrae that were recovered had unique features. In the transverse section of the vertebrae, subtriangular and laterally directed processes were observed. It also has ventrally sharp central.

Similar features were also seen in the other dinosaurs of the family. Each vertebra of the dinosaur supported prezygapophyses, but their spinal processes were very poorly developed. It is possible that they absolutely lacked the spinal processes. The scapula was smaller in comparison to the dinosaurs of the other genera, and they lacked the fused astragalus and calcaneum, unlike its relatives. The dinosaur had a long tail.

The length of the tail covered half the length of the body. They had a long s-shaped neck with short hands and long limbs. The arms possibly had a single digit which ended in long and strong claws with as seen in the Alarezsaurids. They probably had feathers or feather-like structures and bird-like hands. So before classifying it as a dinosaur, the Alvarezsaurus was known to be a flightless bird. They were different from the other dinosaurs of the Late Cretaceous and were considerably larger than the other genera of Alvarezsaurids. The name of this lizard-hipped dinosaur means Alvarez's lizard.

Alvarezsaurus was considered to be flightless birds.

How many bones did an Alvarezsaurus have?

The total number of bones present in the Alvarezsaurus skeleton is unknown; the entire bone structure of A. cavoli has not been recovered from their range. This type of genus of the dinosaur is the least understood one among the other genera. They are only known from the partial pelvis, partial hindlimb, teeth, and the vertebrae that have been recovered from the Bajo de la Carpa Formation.

How did they communicate?

Dinosaurs communicated through vocalization. Their developed visuals also help them to communicate.

How big was the Alvarezsaurus?

The average Alvarezsaurus size is estimated to be around 4.6 ft (1.4 m). They are two times smaller in length than a Gondwanatitan.

How fast could an Alvarezsaurus move?

The Alvarezsaurus were small and fast-running dinosaurs, but their speed has not been estimated.

How much did an Alvarezsaurus weigh?

The weight of an Alvarezsaurus ranged between 5-20 lb (2.27-9.1 kg).

What were the male and female names of the species?

The male and the female dinosaurs do not have any specific names. Both of them are referred to as Alvarezasaurus.

What would you call a baby Alvarezsaurus?

A baby dinosaur is referred to as a nestling or hatchling.

What did they eat?

The Alvarezsaurus was carnivorous in nature. They can also be identified as insectivorous since they mainly ate insects. They possibly used their claws to dig out the termites and ants. They probably had pointed snout, which could be an adaptation to feed on insects. However, since their skull has not been discovered, there is no strong evidence for this fact.

How aggressive were they?

Although they were carnivores, they mainly fed on insects and termites. This makes them less aggressive than the more powerful flesh-eating dinosaurs.

Did you know...

The Alvarezsaurus was thought to be the earliest flightless bird in the world, but this possibility is now discarded by researchers; they now include them as one of the Maniraptora.

Why are they called Alvarezsaurus?

The name Alvarezsaurus denotes one of the members of the Alvarezsauridae family of Late Cretaceous dinosaurs whose fossil was discovered from the Bajo de la Carpa Formation in South America. The Alvarezsaurus was first discovered in 1991 by the paleontologist Jose Bonaparte. He named the species Alvarezsauruus after the name of Don Gregorio Alvarez. Alvarez was a historian and geologist of Argentina.

Often Don Gregorio Alvarez is confused with another amateur paleontologist and physicist, Luis Alvarez. Luis Alvarez was the author of the Alvarez Theory of Extinction which described how an asteroid attack was responsible for the extinction of dinosaur species from earth.

The name of the type species of the Alvarezsaurus is Alvarezsaurus calvoi. The Greek term Sauros means lizard in Engish. So the complete name Alvarezsaurus translates to Alvarez's lizard. The explanation behind naming their type species Alvarezsaurus calvoi is unknown.

Who discovered Alvarezsaurus?

The Alvarezsaurus is the type genus of the Alvarezsauridae family of dinosaurs. The dinosaur is named after the geologist and historian Don Gregorio Alvarez of Argentina. In 1991, the paleontologist Jose Bonaparte found an incomplete skeleton in the Bajo de la Carpa Formation. It was located in Patagonia, which is currently known as Argentina.

Bonaparte was the first one to describe the type species Alvarezsaurus calvoi. It was the first Alvarezssaurid ever described after the discovery of the family. He was also responsible for naming the family of Alvarezsaurids and strongly suggested that these dinosaurs are closely related to the group of ornithomimid dinosaurs.

After Bonaparte, several other paleontologists discovered a few types of dinosaurs having features similar to the Alvarezsaurid dinosaur but were classified under distinct genera. At present, many specimens of Alvarezsaurids have been discovered from different parts of the world, and they are classified under distinct genera. Most of these groups of dinosaurs belonged to the Late Cretaceous period.

Here at Kidadl, we have carefully created lots of interesting family-friendly dinosaur facts for everyone to discover! For more relatable content, check out these Abrosaurus facts, or Huaxiaosaurus facts for kids.

You can even occupy yourself at home by coloring in one of our free printable family of four dinosaurs coloring pages.

Main image by Karkemish

Second image by FunkMonk (Michael B. H.)

Alvarezsaurus Facts

What Did They Prey On?

Ants and termites

what Type of Animal were they?


Average Litter Size?


What Did They Look Like?


How Much Did They Weigh?

5-20 lb (2.27-9.1 kg)

Skin Type

Possibly had feathery skin

How Long Were They?

4.6 ft (1.4 m)

How Tall Were They?










Scientific Name

Alvarezsaurus calvoi

What Were Their Main Threats?

Natural disasters

What Habitat Did They Live In?

Terrestrial habitat

Where Did They Live?

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Written by Moumita Dutta

Bachelor of Arts specializing in Journalism and Mass Communication, Postgraduate Diploma in Sports Management

Moumita Dutta picture

Moumita DuttaBachelor of Arts specializing in Journalism and Mass Communication, Postgraduate Diploma in Sports Management

A content writer and editor with a passion for sports, Moumita has honed her skills in producing compelling match reports and stories about sporting heroes. She holds a degree in Journalism and Mass Communication from the Indian Institute of Social Welfare and Business Management, Calcutta University, alongside a postgraduate diploma in Sports Management.

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