Lesson3

Lesson 3: Eating

• Authors: W. Scott Persons, Victoria Arbour, Jessica Edwards, Matthew Vavrek, Philip Currie, Eva Koppelhus

• Learning Objectives:

  • Understand various feeding habits and adaptations of major dinosaur groups.

  • Describe morphological characteristics of different animal feeding strategies.

Overview of Dinosaur Evolution

• Spanning over 160 million years, dinosaurs evolved into a diverse array of forms.

• Ancestors were likely carnivorous, feeding on small reptiles and large insects.

• Adaptations evolved to suit different diets, critical for understanding ecosystem interactions.

• Fossil gut contents from rare finds provide insights into dinosaur diets, but most dietary information comes from comparing fossilized structures with modern animals.

Feeding Adaptations of Dinosaurs

• Herbivores:

  • Features thin, ridged or leaf-shaped teeth for shearing and broad, flat teeth for grinding plant material.

  • Modern birds lack teeth but herbivorous birds have short, triangular beaks.

  • Examples: Giraffe-like adaptations for browsing,

• Carnivores:

  • Equipped with sharp, pointed teeth for piercing and hooked claws for capturing prey.

  • Carnivorous dinosaurs show similarities to modern raptorial birds with sharp beaks and claws.

  • Features serrations on teeth that assist in slicing flesh, similar to serrated knives.

Specialized Feeding Strategies

• Frugivores:

  • Example: Parrots have sharp, hooked beaks for tearing fruit peels.

• Piscivores:

  • Specialized in feeding on fish with tall, sharp conical teeth for holding slippery prey, such as the Gharial crocodilian.

  • Example: The Common Loon with its spear-shaped beak.

• Insectivores:

  • Examples: Shrews and hedgehogs have sharp teeth for puncturing insects, while some have weak jaws and no teeth (anteaters).

  • Digging adaptations: large claws and strong limbs are common.

• Durophagy:

  • Some carnivores (e.g., hyenas, alligators) have strong teeth for cracking bones, requiring powerful jaws.

Omnivores

• Consume both plants and animals, displaying a range of tooth shapes like pointed canines (characteristic of carnivores) and molars (characteristic of herbivores).

• Examples include humans, pigs, and many bears.

Tooth Replacement in Dinosaurs

• Learning Objective 3.2:

  • Humans have limited sets of teeth; dinosaurs, like sharks, continuously grow new teeth.

  • Process:

    • New teeth replace old ones, the root is reabsorbed before shedding.

    • Estimates suggest T. rex replaced teeth every 1.5-2 years.

  • Shed teeth provide insights into carnivorous diets, indicating feeding behavior.

Processing Plant Material

• Learning Objective 3.3:

  • Plant cell walls contain cellulose, difficult for animals to digest without bacteria.

  • Chewing aids in digestion.

• Dental Batteries:

  • Found in hadrosaurs and ceratopsians; comprised of densely packed teeth for grinding.

  • Characterized by rapid tooth replacement to replenish wear from chewing.

Adaptations in Hadrosaurs and Ceratopsians

• Hadrosaurs:

  • Chewing surfaces angled slightly downward, involved both horizontal and vertical jaw movements.

• Ceratopsians:

  • Vertical dentition that acted like scissor blades for efficient grinding.

  • Both types had inset teeth aiding in chewing capacity.

Non-Morphological Indicators of Diet

• Learning Objective 3.4:

  • Fossil gut contents (cololites) provide valuable diet information.

  • Examples include:

    • Hadrosaur and ankylosaur gut contents displaying plant material.

    • Carnivorous dinosaurs like Sinocalliopteryx with contents indicating consumption of small dinosaurs and birds.

• Coprolites:

  • Fossilized dung yields knowledge on diet and digestive processes.

  • Example: Tyrannosaurus coprolites containing bone fragments confirm durophagy.

Conclusion and Future Learning Objectives

• Learning Objective 3.5:

  • Interpret possible diets based on fossil record and anatomy comparisons.

  • Assess whether a specific dinosaur was a carnivore or herbivore based on evidence.

Supplementary Materials

• Various blog posts and visualizations detailing dinosaur diets and feeding habits.

• Examples include discussions on hadrosaur and ceratopsian chewing movements and the diets of other dinosaurs.