Anserimimus: The Goose Mimic of the Late Cretaceous

Anserimimus: The Goose Mimic of the Late Cretaceous

Among the prehistoric dinos of the Late Cretaceous, there was one that stood out not for its size or ferocity, but for its peculiar resemblance to a creature we are all familiar with today–the goose. This dinosaur is known as Anserimimus, a name that fittingly translates to “goose mimic.”


Anserimimus, a member of the theropod group, was a fascinating creature that lived at the very end of the Age of Dinosaurs. It bore a striking resemblance to the modern-day goose, hence its name. But don’t let the name fool you. While it may have looked somewhat like a goose, it had its own unique features that set it apart from its avian relative. 

Anserimimus Key Facts

Anserimimus pronunciationAn-ser-im-eye-mes
Meaning of nameGoose Mimic
Type SpeciesAnserimimus planinychus
When it Lived72.1 to 66.0 MYA
PeriodLate Cretaceous
Length9.8 ft
Height3.9 ft
Weight100-120 lbs
MobilityMoved on two legs
First DiscoveryLate 1970 during a joint Soviet-Mongolian expedition
Location of first findBugiin Tsav, Mongolia
First Described by1988 by Rinchen Barsbold
HolotypeSPS GIN AN MPR 100/300

Anserimimus Origins, Taxonomy, and Timeline

A sketch of an Anserimimus, a bipedal dinosaur characterized by its long neck and tail, small head, and feather-like structures on its forelimbs. This dinosaur, belonging to the Late Cretaceous period, likely fed on small animals and insects, making it an omnivore.

The name Anserimimus is derived from the Latin “anser” meaning goose and the Greek “mimos” meaning mimic–a fitting moniker for a dinosaur that bore a striking resemblance to the modern-day goose. This name serves as a constant reminder of the fascinating connections and parallels between the prehistoric world of dinosaurs and the present-day animal kingdom.

Anserimimus belongs to the Theropoda group, a diverse group of bipedal dinosaurs. More specifically, it is a member of the Ornithomimidae family. The genus is represented by a single type species, Anserimimus planinychus. While it doesn’t have any other known species or subspecies, its unique characteristics make it a fascinating subject of study in the world of paleontology.

The timeline is situated in the Late Cretaceous period, specifically the Maastrichtian epoch. This was a time of significant change and diversity in the dinosaur world and Anserimimus was a part of this dynamic ecosystem.

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Discovery & Fossil Evidence

The first discovery of Anserimimus was made in the late 1970s  during a joint Soviet-Mongolian expedition in Bugiin Tsav, Mongolia. This initial find was a significant contribution to our understanding of this unique dinosaur and its place in the prehistoric world.

A fossil skeleton of Anserimimus displayed in a museum exhibit. This bipedal dinosaur from the Late Cretaceous period is shown with its elongated neck and tail, slender body, and well-preserved bones, indicating its omnivorous diet.
Jordi Payà from Barcelona, Catalonia, CC BY-SA 2.0, via Wikimedia Commons

The holotype specimen, designated as SPS GIN AN MPR 100/300, provided valuable insights into the physical characteristics and potential behaviors of Anserimimus. The fossil evidence revealed a dinosaur that was distinctively bird-like in its physical attributes, lending credence to its name as the “goose mimic.”

Subsequent finds have also been made in Mongolia, further expanding our knowledge of this dinosaur. Each new discovery adds another piece to the puzzle, helping to paint a more complete picture of this fascinating dinosaur and its life during the Late Cretaceous period.

Anserimimus Size and Description

This was a unique dinosaur with a distinctive physical appearance. Its body was streamlined and built for speed with a long neck and tail that helped to maintain balance while running. Its head was small and bird-like and it had large eyes that suggest it may have been active during the day.

Short Description of Anserimimus

It had a long, slender body, with a neck and tail that were elongated to aid in balance. Its head was small and bird-like and its large, forward-facing eyes that suggest it was a diurnal creature. The dinosaur’s limbs were well-adapted for running, with powerful hind legs and three-toed feet. Its forelimbs were shorter and ended in three fingers. These were likely used for foraging and handling food. The skin is believed to have been covered in feathers, further enhancing its bird-like appearance.

Size and Weight of Type Species

The exact size and weight are not definitively known, as complete skeletons have not been found. However, based on the available fossil evidence it is estimated that Anserimimus was a medium-sized dinosaur. Its estimated length is around 3 meters and its estimated weight is around 50 kilograms. As more discoveries are made and our understanding of this fascinating creature continues to grow, we may yet gain a more accurate picture of its true size and weight.

The Anserimimus in Detail

This dinosaur is a reminder of the incredible diversity and adaptability of life during the Late Cretaceous period. Its bird-like appearance and its dinosaur lineage paints a fascinating picture of a creature that was as much a part of its environment as it was a product of it.

One of the most distinctive features of Anserimimus was its long, slender legs. These were well-adapted for speed, suggesting that it was a fast runner. This would have been a crucial survival trait that allowed it to outrun predators or chase down prey. As another characteristic feature of theropods, it had three-toed feet that would have provided stability and grip as it moved across the diverse terrains of its habitat.

The forelimbs were shorter than its hind legs and ended in three fingers. These could have been used for a variety of tasks, from foraging for food to interacting with its environment. The presence of feathers on its body further underscores its bird-like appearance and could have had various functions, from insulation to display.

The fossil record is not as extensive as some other dinosaurs but has nonetheless provided valuable insights into this unique dinosaur. The holotype specimen, SPS GIN AN MPR 100/300, is a particularly notable example. Discovered by paleontologist Rinchen Barsbold in the late 1970s, this specimen has been instrumental in shaping our understanding of Anserimimus and its place in the dinosaur world.

The Anserimimus in its Natural Habitat and Environment

An illustration of two A. planinychus, a type species of the Anserimimus genus, showcasing their feathered bodies and agile builds. These Late Cretaceous omnivorous dinosaurs are depicted with long necks, small heads, and sturdy legs, emphasizing their ability to move swiftly and hunt or forage effectively.
Photo Credit: vikadinosauris

The world at the time of this dinosaur was a vibrant and dynamic one. The Late Cretaceous period was characterized by diverse ecosystems with a wide range of flora and fauna. Anserimimus, as an omnivore, would have been a part of this complex web of life as it fed on a variety of foods from plants to small animals.

The physical adaptations of this dinosaur, from its slender legs to its three-toed feet, suggest a creature well-adapted to its environment. It likely inhabited a range of habitats, from forested areas to open plains. Its speed would have allowed it to traverse these landscapes efficiently in order to forage for food or evade predators.

The social behavior of this dinosaur is not well-known. Like many other theropods, it may have been a solitary creature that only came together with others of its kind for mating or possibly communal nesting. However, this is largely speculative and more research is needed to confirm or reject these hypotheses.

Interesting Points about Anserimimus

  1. This is one of the few dinosaurs that has a name derived from a modern-day bird, the goose. This is due to its bird-like appearance and possible behavior.
  2. Despite being a theropod, a group that includes some of the most ferocious carnivores like Tyrannosaurus rex, Anserimimus was most likely an omnivore that fed on both plants and small animals.
  3. The discovery of Anserimimus in Mongolia adds to the rich diversity of dinosaur species found in this region, making it a hotspot for paleontological research.
  4. It is believed to have been a fast runner thanks to its long, slender legs. This would have been crucial for survival in the Late Cretaceous period.
  5. The presence of feathers, a feature it shares with many other theropods, suggests a close evolutionary relationship with birds.

Contemporary Dinosaurs

In the late Cretaceous, the vast plains of what is now Mongolia were home to many prehistoric creatures. One such dino was the nimble Anserimimus, a fleet-footed omnivore that stood roughly the same size as a modern ostrich.

The bone-crushing jaws of the Tarbosaurus would have been a constant threat. Moreover, turning the Anserimimus’s quest for food into a high-stakes game of hide and seek. Yet, the Anserimimus was not just a prey. It was also a predator, its sharp eyes possibly scanning for eggs. A potential victim could have been the Saurolophus–a dinosaur roughly the size of a small motorhome. It might have grazed peacefully nearby, oblivious to the danger.

The Anserimimus also shared its world with the Nemegtosaurus, a long-necked herbivore that towered above it like a living skyscraper. This gentle giant focused on the leafy treetops and may have been oblivious to the Anserimimus scurrying beneath its feet. Meanwhile, the Tarchia was an armored dinosaur about the size of a compact car. This dinosaur had a formidable presence compared to the Anserimimus. Its spiked tail could deliver a lethal blow, forcing the Anserimimus to use speed and agility to avoid conflict.

In this prehistoric tableau, the Anserimimus was a central figure. Its life intertwined with those of its contemporaries in a complex web of predator and prey, competition and coexistence. Through the lens of the Anserimimus, we glimpse the vibrant, often perilous world of the Late Cretaceous. This was a world where survival was the ultimate prize.

List of All Dinosaurs

We have created a list of all dinosaurs we have covered here, sorted across the seven main groups of dinosaurs. We also include information about their type of diet, (omnivore, herbivore or carnivore) and the time they lived.

Frequently Asked Questions

What does the name mean?

The name translates to “goose mimic,” reflecting its bird-like appearance and possible behavior.

What did this dinosaur eat?

It was an omnivore that ate both plants and small animals. This contrasts its theropod lineage, as they are usually carnivores.

When did Anserimimus live?

It lived during the Late Cretaceous period–specifically the Maastrichtian epoch–approximately 72.1 to 66.0 million years ago.

Where were the fossils found?

The fossils were first discovered in Bugiin Tsav, Mongolia, during a joint Soviet-Mongolian expedition in the late 1970s.

What group of dinosaurs does Anserimimus belong to?

This dinosaur belongs to the Theropoda group, and more specifically, it is a member of the Ornithomimidae family.

Did Anserimimus have feathers?

Yes, it is believed to have been covered in feathers that further enhanced its bird-like appearance.


The information in this article is based on various sources, drawing on scientific research, fossil evidence, and expert analysis. The aim is to provide a comprehensive and accurate overview of the Anserimimus. However, please be aware that our understanding of dinosaurs and their world is constantly evolving as new discoveries are made.

Article last fact-checked: Joey Arboleda, 07-25-2023

Featured Image Credit: Levi bernardo, CC BY-SA 3.0, via Wikimedia Commons