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Fukui Prefectural Dinosaur Museum FAQ about dinosaurs

FAQ about dinosaurs

Protection

Antipredator Device
There was a predator-prey relationship among dinosaurs. Predators use claws and teeth for attacking, and prey, typically herbivorous dinosaurs, protect themselves with armor or spikes.
Ankylosaurian Defence
Ankylosaurs are covered with armor for protection and have tail clubs to defend from predators.
Stegosaurian Defence
Stegosaurs have spikes at the end of their tail. They may have swung their tail to protect themselves from predators.
Skin Structure
Dinosaur skins are studied based on skin impressions. Some dinosaurs have "scales" like crocodiles. Recent discoveries of theropod dinosaurs from China show that some dinosaurs have feathers.
Footprints
The shape of dinosaur foot pads is reconstructed from footprints. Some dinosaur footprints preserve skin impressions of foot pads that are similar to birds and crocodiles.
Regulation of Body Temperature
Stegosaurs have plates on the back of their bodies. The structure of the plates indicates that they might have been used for heat absorption or release. Some theropods are found with feathers, which were probably used for insulation.
Ectothermy or Endothermy
Warm-bloodness in dinosaurs has been debated, and much evidence suggests that dinosaurs were warm-blooded like birds and mammals. Close relationships between small theropods and birds have been supported, suggesting some small theropods were warmblooded.

Locomotion

Osteology
Dinosaurs are tetrapods that have two fenestrations on the side of their skull, and have teeth in sockets. The arrangement of the hip bones can divide dinosaurs in two groups. Dinosaurs have an upright posture.
Gaits
Dinosaur footprints show how they walked. Most are either bipedal or quadrupedal. Some dinosaurs such as Iguanodon may have used their forelimbs when walking at a slow speed.
Running Speed
The running speed of dinosaurs can be hypothesized by studying bone morphology and footprints. Shapes and proportions of limb bones tell us that fast runners have longer limb bones towards the end of their limbs and have lightly built limbs; conversely, slow movers have shorter limb bones towards the end of their limbs and well-developed articular processes/surfaces with massive muscles. Absolute running speed can be estimated by using a model with the length of stride from footprints and leg length, compared to the same parameters in living animals.
Behavior Based on Footprints
Footprints will tell us about dinosaur behavior as well as locomotion. Dinosaur footprints from Texas, USA, show that a theropod dinosaur has chased a sauropod dinosaur. Also, some sauropod dinosaur tracks indicate that sauropods migrated as a herd.

Hearing and Vision

Intelligence
It is impossible to measure the IQ of dinosaurs. However, dinosaur skulls or the cast of dinosaur braincases can be used to estimate the shape and volume of brains, providing us a way to study "intelligence" in dinosaurs.
Measuring Brain Size
Computed tomography is used as a method to measure and obtain characteristics of dinosaur brains without breaking fossils.
Encephalization Quotient
Encephallization Quotient (EQ) can be used to estimate the intelligence of dinosaurs. EQ is defined as the ratio of measured brain size and estimated brain size based on its body size, but it is different from IQ (Intelligence Quotient). The measurement of brain size of dinosaurs can be estimated by CT scan images.

Diet

Food Habits
In general, theropod dinosaurs fed on other animals, and sauropod and ornithischian dinosaurs ate plants. Coprolites are studied to understand dinosaur diets. In coprolites, incompletely digested foods (e.g., fish scales, pollen) are preserved. Recently, stomach stones were reported from theropods, and it has been argued that some theropods might have fed on plants.
Tooth Shape
Tooth shape differs among dinosaurs, depending on their diets. Carnivorous dinosaurs have recurved, serrated teeth to slash meat. Herbivorous dinosaurs have more variations in tooth morphology and complex teeth, adapted for feeding on plants.
Tyrannosaurus Teeth
Tyrannosaurus had large teeth. A Tyrannosaurus tooth is more than 30 cm in length from the tip of tooth to its root. The front and back of the tooth crown have serrations like a saw. At the base of each serration, there is a groove so that blood could flow along the groove when a tyrannosaur slashed its prey.
Digestion
The physiology of the alimentary tract of dinosaurs is not known because it is not preserved in fossils. Some fossil evidence (e.g., teeth, coprolites, and stomach stones) can be studied to understand the biology of dinosaurs.
Psittacosaurus Gastroliths
Psittacosaurus is a small (2 m long) herbivorous dinosaur and had a beak like parrots. The dinosaur lived close to lakes or rivers. Psittacosaurus found from China has small pebbles, gastroliths, in the stomach region.
Attack and Defence of Dinosaurs
Theropod dinosaurs attacked with large claws and sharp teeth. For defence, sauropods and ankylosaurs swung a tail club, ceratopsians used horns, and stegosaurs utilized spines on their tail. Males may have fought and competed to acquire a female.
Fighting Dinosaurs (Velociraptor and Protoceratops)
Velociraptor was found with Protoceratops from the Gobi Desert, Mongolia. The arm of Velociraptor is being bitten by Protoceratops, with the interpretation that these dinosaurs were buried while they were fighting.
Tooth Marks in Dinosaur Bones
A set of grooves running parallel each other is sometimes preserved on fossil bones. These grooves, called tooth marks, were formed when a carnivorous dinosaur with serrated teeth bit on a bone.

Reproduction

Identification of Dinosaur Eggs
Eggs with mineralized shells are known in birds and reptiles as well as dinosaurs. The structure of eggshells differs in different animals, which helps to identify dinosaur eggs.
Columnar Structure of Dinosaur Eggs
Dinosaur eggshell is composed of columns 500 µm in cross-sectional diameter. The outer surface is rough due to the columns, and the inside surface is ornamentated by a mammillary layer. This structure is strong against pressure from the outside but weak from inside.
Variations of Dinosaur Nests
The shapes of eggs as well as nests are different among dinosaurs. Nest shapes vary, including conical and arc-shaped nests as well as bowl-shaped nests with mounds.
Differences in Dionsaur Eggs
Dinosaur eggs differ in different dinosaurs, ranging from 2 cm to 70 cm in diameter. The structures of dinosaur eggshells are different in different kinds of dinosaurs as well.
Brooding Over Eggs
Brooding behavior in dinosaurs had been argued about for a long time. Discoveries of Oviraptorid from China and Mongolia were found in a brooding position over eggs.
Nesting Oviraptorid
A theropod closely related to Citipati was found brooding over eggs. Its fore and hind limbs were folded, covering the eggs as birds do.
Oviraptorid Embryo
This is the embryo of Citipati before hatchling, discovered from the Gobi Desert, Mongolia, by the collaboration of reserchers from Mongolia and USA in 1993. The skeleton of the embryo is preserved within an egg. This discovery increased our knowledge on how the dinosaur embryo was enclosed in an egg.
Parental Care
Discoveries of Maiasaura with eggs and babies in nests from Montana, USA, provided evidence of the parental care, protecting and feeding helpless babies in dinosaurs. Other dinosaurs from China and Mongolia also have been found with juveniles, indicating parental care.
Maiasaura Nesting Grounds
Maiasaura, which means "good-mother lizard", was found with clutches of eggs and babies, allowing us to understand parental care behavior. Their nests, 2 m in diameter, were formed 7 m apart.
Nests of Maiasaura
The nests of Maiasaura are 2 m in diameter and 90 cm in depth. Fifteen baby skeletons of Maiasaura have been found in a nest. Plant material, which might have been used to form the nests, was found within the nests.
Ontogenetic Variation
A modern ground bird, the ostrich, grows up to an adult form with a body length of 2.2 m in one and half years. The modern crocodile takes roughly seven years to become an adult but keeps growing throughout its lifetime. Among dinosaurs, it has been hypothesized that Maiasaura reached an adult form in seven years, and some prosauropods did so in 15 years.
Growth Series of Dinosaur Footprints
Iguanodontian dinosaur footprints have been found from the Katsuyama Quarry of Fukui Prefecture. They ranged from 8 to 60 cm, indicating that juvenile and adult iguanodontians have lived in this region.
Sexual Dimorphism
Sexual differences (sexual dimorphism) of dinosaurs can be determined from bone shapes. Some lambeosaurines have differences in the size of the "crest" on the skull, and some ceratopsians have variations in shapes and orientations of horns, which have been considered sexual dimorphisms.