Life habits of Iguanodon
Iguanodon's teeth are similar to those of iguanas, but larger. The platypus has many rows of teeth that are constantly changing, while the Iguanodon has only one pair of teeth ready to be changed at the same time. There are at most 29 teeth on the left and right sides of the maxilla, but there are no teeth on the anterior maxilla, and there are 25 teeth on the left and right sides of the odontoid bone. The reason why the number of teeth in the upper and lower jaws is inconsistent is that the teeth in the lower jaw are wider. Because these teeth are located on the outside of the lower jaw and other physiological characteristics, Iguanodon is thought to have some kind of cheek pouch, which may be composed of muscles and can chew food on both cheeks, just like most other birds and hip dinosaurs.
When the Iguanodon's mouth is closed, the buccal surfaces of the upper and lower jaws will touch each other, and food can be ground in the middle, forming a chewing action similar to that of mammals. Because Iguanodons' teeth are constantly changing, they can eat hard plants all their lives. In addition, Iguanodon lacks teeth at the front end of the maxilla and mandible, forming a blunt edge, which may be covered with keratin and can bite off branches. Iguanodon's little finger is slender and flexible, which can help catch food.
It is not clear what kind of plants Iguanodons usually feed on. Larger species may feed on leaves within 4.5 meters above the ground, such as Benisal Iguanodon. David norman thought Iguanodon might have eaten equisetum, cycads and conifers. It is generally believed that the emergence of flowering plants in Cretaceous is related to Iguanodon, which is caused by these dinosaurs eating low-altitude vegetation. According to the hypothesis, because Iguanodons feed on gymnosperms, early angiosperms like grass have room to grow, but there is no evidence to prove it. No matter what kind of plants Iguanodons feed on, they should occupy the niche of medium and large herbivores according to their size and prosperity. Iguanodon coexisted with the following dinosaurs in Britain: E Long, a small predator, Tyrannosaurus Rex, Deinonychus, Neosaurus, small herbivorous dinosaurs, odontosaurus and desert dragon, Mantellosaurus of Iguanodontidae, Spiny Ankylosaurus of Ankylosaurus, and Anomalous Dragon of sauropods. Mantel's reconstruction map of Iguanodon based on fossils from maidstone, England. Early Iguanodon fossils were very broken, which made scientists have different views on Iguanodon's gait. Iguanodon was originally described as a quadruped with horns on its nose. With the discovery of more fossils, Mantel found that the forelimbs of Iguanodon were much shorter than the hind limbs. His opponent, richard owen, thought Iguanodon was a short and fat animal with columnar limbs. The first original scale reconstruction of dinosaurs was entrusted to Mantel, but he refused on the grounds of poor health. These Iguanodon sculptures were later based on Owen's version.
After discovering a large number of Iguanodon fossils in Benishat, scientists found that Iguanodon was a biped. However, at that time, the shape of Iguanodon was upright, and its tail dragged on the ground as the third fulcrum of the tripod.
David norman later re-examined the Iguanodon fossils. He thinks that Iguanodons can't walk upright because they have hardened tendons on their tails. If a tripod is used, the rigid tail of Iguanodon will be broken. If Iguanodons take a horizontal posture, they can better understand the characteristics of their arms and shoulder straps. For example, Iguanodon's hand is quite inflexible, with three fingers in the middle together and hoof-shaped fingers on it. This hand structure can bear more weight. Iguanodon's wrist is quite inflexible, and his arms and shoulders are very strong. These characteristics make Iguanodon adopt quadruped gait more.
With the increase of Iguanodon's age and weight, they will adopt quadruped gait more; The arm of juvenile Bayeuodon is shorter than that of adult, which is about 60% of the length of hind limb, while the length of forelimb of adult is 70% of the length of hind limb. According to the fossil footprint of Iguanodon and the structure of Iguanodon's hands and arms, it can be inferred that the middle three hoofed fingers can support the weight when Iguanodon adopts four-legged gait. Iguanodon's hind paw is quite long, with three toes on it. They will walk with their fingers and claws like animals walking on their toes. Iguanodon's maximum speed of running on two legs is estimated to be 24 kilometers per hour, but they can't run fast on four legs.
Many large three-toed footprints were found in the early Cretaceous strata of England, especially in Wilder and Isle of Wight. These footprint fossils were difficult to describe and explain at first. Some early researchers thought they were related to dinosaurs. 1846, Edward Taggart classified these footprint fossils into the genus Iguanodon in the taxonomic unit; Samuel Beckles found these footprints in 1854, which are similar to those of birds, but probably from dinosaurs. 1857 found the hind limbs of a young Iguanodon with three toes on its foot, indicating that these footprints may have come from Iguanodon. Despite the lack of direct evidence, these footprint fossils are usually classified as Iguanodons. A fossil footprint in England shows that Iguanodon may have walked on all fours, but the footprint itself is not well preserved, so it is difficult to be used as direct evidence. Footprint fossils classified as Iguanodon are located in Bergen and Svalbard in Europe and Norway, where Iguanodon fossils have been found. The earliest discovered Iguanodon claws were found in Germany 1840. The sharp claws of the thumb are one of the most famous features of Iguanodon. Although Mantel initially put the thumb paw on the nose of Iguanodon, according to the complete specimen discovered by Benishat, Dawro put the thumb paw in the correct position on his hand. However, since 1980s, there are still many dinosaurs whose thumbs and paws are dislocated on their feet, which are similar to Chironomidae, such as Argentinosaurus Northwest, Byron Dragon and Giant Raptor.
Iguanodon's thumb claws are considered as close-range weapons against predators, similar to daggers, but they may also be used to dig fruits and seeds and even fight other Iguanodons. A scientist thinks that this thumb claw is connected with poisonous glands, but this view is not accepted because the inside of the claw is not hollow and there is no groove on the surface to let the venom flow. A large number of Iguanodon fossils in Benishat are sometimes thought to be caused by a single disaster, while others are thought to be caused by many reasons. According to the theory of group life, there are at least three ways of death in this area, and a large number of individuals died in a very short geological time (about 10 to 100), but this does not mean that Iguanodons are social animals. Young Iguanodon fossils in Benishat are very common, which is different from the death mode of modern social animals. It may be that periodic floods pour a large number of bodies into lakes or swamps.
The age range of Iguanodon fossils in Neiden, Germany is very large, even six times that of Mantellosaurus and Benisal Iguanodon. According to the geographical features, it shows that some social animals may have migrated through rivers.
Unlike other supposed social animals, such as hadrosaurs and ceratosaurus, there is no evidence that Iguanodons are hermaphroditic. Some people think that Mansfield Iguanodon or Atherfield Iguanodon (both of which are currently Mantell Iguanodon) represent a certain sex of Iguanodon, which may be female, while Benisal Iguanodon, which is bigger and stronger, may be male. However, this theory has not received any support.