Iguanodon

Overview

Iguanodon bernissartensis was a large, herbivorous dinosaur that lived during the Early Cretaceous period, approximately 125 to 110 million years ago. It was one of the first dinosaurs ever discovered and played a pivotal role in the early study of paleontology.

Iguanodon was a robust dinosaur, measuring up to 33 feet (10 meters) in length and weighing around 4 tons. It is best known for its distinctive thumb spikes, which were likely used for defense or foraging.

Quick Facts

Diet

Herbivore (plants, leaves, and shrubs)

Speed

~12 mph (estimated)

Weight

~4 tons (3,600 kg)

Length

~33 ft (10 m)

Defense

Thumb spikes for protection

Discovery & Significance

Iguanodon was one of the first dinosaurs to be scientifically described. Its fossils were discovered in 1822 by Gideon Mantell in England. The name “Iguanodon” means “iguana tooth,” reflecting the similarity of its teeth to those of modern iguanas.

Iguanodon played a crucial role in the early understanding of dinosaurs. It was one of the three genera used to define the group Dinosauria, alongside Megalosaurus and Hylaeosaurus. Its discovery helped shift the perception of dinosaurs from slow, lizard-like creatures to dynamic and diverse animals.

Physical Characteristics

Iguanodon had a large, bulky body with strong hind limbs and shorter forelimbs. Its most distinctive feature was its thumb spikes, which were likely used for defense against predators or for breaking down vegetation. Its teeth were adapted for grinding plant material, and it had a beak-like structure at the front of its mouth for cropping plants.

Iguanodon could walk on both two and four legs, depending on its needs. Its tail was stiffened by ossified tendons, providing balance while walking or running. Fossilized footprints suggest that Iguanodon lived in herds, which would have provided protection against predators.

Iguanodon vs. Other Herbivorous Dinosaurs

More Details

Iguanodon lived in what is now Europe, North America, and Asia during the Early Cretaceous. Its environment was characterized by lush forests and river systems, which provided ample vegetation for feeding. Iguanodon was a versatile herbivore, capable of browsing on low-lying plants and reaching higher vegetation when necessary.

The thumb spikes of Iguanodon have been the subject of much debate. Initially thought to be a nasal horn, they were later identified as thumb spikes. These spikes were likely used for defense against predators like Baryonyx or for breaking down tough plant material. Iguanodon’s teeth were continuously replaced, allowing it to efficiently process large amounts of vegetation.

Fossilized trackways and bonebeds suggest that Iguanodon lived in herds, which would have provided protection against predators and facilitated social behavior. Its ability to walk on two or four legs made it a highly adaptable dinosaur, capable of both grazing and browsing.

References & Further Reading