Dilophosaurus: The Complete Guide to the Double‑Crested Predator

With its distinctive pair of crests on its skull, Dilophosaurus is one of the most recognizable dinosaurs from the Early Jurassic. Popularized by Jurassic Park as a small, frill‑necked, venom‑spitting creature, the real Dilophosaurus was quite different: a large, powerful predator that was one of the first giant theropods. Its discovery in the 1940s helped shape our understanding of the early evolution of large carnivorous dinosaurs.

In this comprehensive guide, we’ll explore everything about Dilophosaurus: its size, anatomy, the function of its crests, its diet, and the myths that have surrounded it.

1. What is Dilophosaurus?

Dilophosaurus wetherilli is a genus of theropod dinosaur that lived during the Early Jurassic period, approximately 193 to 183 million years ago. Its name means “two‑crested lizard” (from Greek di “two,” lophos “crest,” and sauros “lizard”), referring to the pair of thin, bony crests on top of its skull. It was one of the largest land predators of its time, representing an early stage in the evolution of large theropods.

Fossils of Dilophosaurus have been found in the Kayenta Formation of Arizona, USA. It is one of the best‑known Early Jurassic dinosaurs, thanks to several complete skeletons. Despite its fame, much about its biology remains debated.

2. Physical Characteristics: Size and Anatomy

Dilophosaurus was a large but lightly built theropod. Here are its key measurements:

• Length: Up to 7 meters (23 feet).
• Height at hips: About 1.5 meters (5 feet).
• Weight: Estimated between 200 and 400 kg (440–880 lbs).
• Skull: Long and slender, with a distinct notch between the premaxilla and maxilla (the “kink” seen in some reconstructions).
• Crests: Two thin, semi‑circular crests on top of the skull, likely made of keratin in life.

Its skeleton was built for speed and agility. The legs were long and slender, and the arms were powerful, with three‑fingered hands bearing sharp claws. The skull was relatively weak, with large gaps between the teeth, suggesting it was not a bone‑crusher.

3. The Crests: Display or Species Recognition?

The function of the crests of Dilophosaurus has been debated. They were thin and relatively fragile, making them unsuitable for combat. They may have been used for:

• Display: They could have been brightly colored to attract mates or intimidate rivals.
• Species recognition: The crests may have helped individuals recognize members of their own species.
• Thermoregulation: Some early ideas suggested they helped cool the blood, but this is unlikely given their small size.

Most paleontologists now agree that the crests were primarily for display, similar to the combs and crests of modern birds.

4. Diet: What Did It Eat?

Dilophosaurus was a carnivore, but its diet is not fully understood. Its skull was relatively weak compared to later large theropods, suggesting it may have preyed on smaller animals, including:

• Small ornithischian dinosaurs like Scutellosaurus
• Lizards and early mammals
• Fish and other aquatic prey (some specimens have been found in river deposits)

It may have used its long arms and claws to grasp prey while delivering bites with its jaws. The notch in its upper jaw could have helped hold struggling prey.

5. Growth and Variation

Several specimens of Dilophosaurus are known, representing different sizes. The largest is estimated at 7 meters (23 feet) in length, while smaller individuals may represent subadults or a different species. A second species, D. sinensis, has been named from China, but its classification is debated.

6. Habitat and Lifestyle: Where Did Dilophosaurus Live?

Dilophosaurus was likely a fast, agile predator, using its speed to chase down prey. It may have also scavenged when opportunities arose.

7. Myths and Misconceptions: Venom and Frills

Dilophosaurus was famously depicted in Jurassic Park as a small, frill‑necked dinosaur that spat venom to blind its prey. This portrayal is entirely fictional:

• Size: The real Dilophosaurus was much larger, reaching 7 meters (23 feet) in length, not the 1.5‑meter (5‑foot) version in the film.
• Frill: There is no evidence of any frill; the crests were on the top of the head, not around the neck.
• Venom: No dinosaur has ever been found with venom‑producing glands, and there is no evidence that Dilophosaurus was venomous.

The movie version has unfortunately shaped public perception, but the real animal was a fascinating predator in its own right.

8. Predators and Competition

Dilophosaurus was the largest predator in its ecosystem, so adult individuals likely had no natural enemies. However, juveniles may have been vulnerable to other predators, including larger individuals of their own species (cannibalism has been suggested for some theropods). Competition with other theropods was minimal, as it was the top predator of its time and place.

9. Discovery and Naming

The first Dilophosaurus fossils were discovered in 1940 by Jesse Williams on the Navajo Nation in Arizona. The specimens were collected by a team from the University of California, Berkeley, and were initially described as two separate species: Megalosaurus wetherilli and a second form later named Dilophosaurus. In 1954, Samuel Welles recognized they belonged to a single animal and named the genus Dilophosaurus.

Later expeditions uncovered more complete skeletons, including several individuals found together, suggesting that Dilophosaurus may have lived in groups. The most complete specimen was described in 1970, cementing Dilophosaurus as one of the best‑known Early Jurassic theropods.

10. Dilophosaurus Gallery

Explore the double‑crested predator

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Final Thoughts

Dilophosaurus was a groundbreaking predator of the Early Jurassic, representing an early experiment in large theropod body plans. Its distinctive crests, slender build, and place in the fossil record make it a favorite among paleontologists. Despite the myths created by popular culture, the real Dilophosaurus remains a fascinating glimpse into the early evolution of the great carnivorous dinosaurs.