The Achillobator was a genus of dromaeosaurid theropod that lived in the Upper Cretaceous period, approximately 90-95 million years ago. It was one of the larger raptors, similar in size to the Deinonychus. The name Achillobator comes from the Greek word for “Achilles’ hero” due to its size and supposed aggression.

Key Facts

Achillobator pronunciationa-KIL-o-BAY-tor
What does Achillobator mean?Achilles’ Hero
Dinosaur typeTheropod
On the menuCarnivorous
Length6 meters
Height1.8 meters
Weight250 kg
Life expectancyUnknown
Legs used to get aroundBipedal
Estimated top speed40 km/h
When they livedUpper Cretaceous era, 90-95 million years ago
Where they have been found?Mongolia

When & Where

The first-ever Achillobator remains were discovered in 1989 in the Bayan Shireh Formation of Mongolia. This theropod lived in what is now the Gobi Desert during the Late Cretaceous period, approximately 90-95 million years ago.

The Achillobator is one of the most interesting – and biggest – raptors in the world. This genus was similar in size to the Deinonychus and closely resembled the Utahraptor, another dromaeosaur. The name Achillobator comes from the Greek word for “Achilles’ hero” in reference to the huge Achilles tendon that supported a sickle-shaped claw on the second toe of each foot. 

It was officially named in 1999 by Mark Norell, Altangerel Perel, and James L. Clark.

Size & Weight

The Achillobator measured 6 meters (20 feet) in length and 1.8 meters (6 feet) in height. It weighed approximately 250 kg (550 lb). This size was perfect for its hunting lifestyle; it was big enough to take down large prey but agile and fast enough to escape predators.

Mobility & Diet

This powerful predator was bipedal and had long hind legs, a long tail, and short arms with three-fingered hands. It was an agile runner and could reach speeds of up to 40 km/h (25 mph). 

The Achillobator was a carnivore and had sharp teeth for tearing flesh. Its diet would have consisted of animals such as lizards, birds, and small dinosaurs.

Interesting Points

  • The Achillobator’s tail was long and curved horizontally to form an S-shape. This unusual feature is thought to have helped the dinosaur balance while running at high speeds.
  • The Achillobator likely had feathers. This is based on the fossil evidence of quill knobs (small bumps that anchor feathers to the skin) on its arm bones.

Featured Image Credit: Durbed, line drawing by Pilsator, CC BY-SA 3.0, via Wikimedia Commons