Animals spend most of their waking hours either searching for food, or eating it. But how do we know what long dead animals like dinosaurs would have eaten. We can't watch them stalk and chase down other animals, like we can in a modern lion. We also can't see if they casually chew their cuds like cows do. However, there is still a lot of information preserved in the fossil record that gives us clues to dinosaur eating behaviors. In this lesson, we'll take you through the different ways paleontologists can unravel the complex food webs of ancient dinosaur communities. All right. Time to start thinking about dinosaur eating habits. Let's start with a quick question. What kinds of things do you think dinosaurs ate? A, plants. B, fish. C, insects. D, other dinosaurs. Or E, all of the above. After all of the different shapes and sizes of dinosaurs that you saw in the first module, it shouldn't come as a surprise that the answer is E, all of the above. Not every dinosaur ate all these things, but different groups of dinosaurs often specialized in consuming one or two of these different food sources, as well as other animals like mammals, amphibians, and so on. When we try to understand the diet or behavior of dinosaurs, we often look at adaptations in modern animals. When it comes to eating some of the most informative parts to look at are the teeth and jaws. We can see general trends in the sizes and shapes of teeth in certain groups of living animals and use our knowledge of these patterns to infer what different dinosaurs would have eaten. With me, I have skulls from a variety of carnivorous and herbivorous animals. Carnivores like this wolf, have sharp teeth for piercing and tearing flesh. You can see the canine here as well as pointed teeth that extend to the back of the jaw. They also have sharp claws for gripping prey. Herbivores on the other hand, have flat teeth for grinding vegetable matter. Like you can see in this horse skull here. Omnivore's like this bear, eat meat and plant matter, so they have a mixture of sharp and flat teeth. Take a look inside of your own mouth. You'll notice you also have a mixture of flat and sharp teeth. That means you’re an omnivore as well. Birds don’t have teeth but birds of prey like hawks, owls and eagles, as well as vultures, have sharp recurve beaks, sharp talons and very strong feet. There are names for a few special subcategories of carnivores. If you eat insects you are an insectivore. Among mammals, most insectivores are small animals like hedgehogs or shrews. They have very sharp teeth for piercing through the exoskeleton of insects. Ant eaters have very powerful limbs and claws for digging up ant hills, termite mounds and rotten logs. Lots of birds eat insects, and most of these have a generalized triangular beak for picking up bugs. While shore birds like this spoon bill, don't necessarily eat just insects, they often have long beaks for probing into mud and sand to eat small invertebrates. Carnivores that are specially adapted to eat fish are called Piscivores. Fish tend to be difficult prey to catch. But once caught, they're not hard to kill and can often be swallowed whole. For these reasons, Piscivores do not need teeth that are adapted for ripping and disemboweling prey, or jaws that are particularly powerful. Instead, Piscivores tend to have elongate jaws that can reach far and snap fast. The teeth of a Piscivore are usually tall and conical, good for spearing and holding on to slippery fish. This is the skull of a gharial, an extant persiverous crocodilian. Note its elongate tweezer-like jaws and its tall, conical teeth that interlock. Many Piscivores also have what is called procumbent dentition. That means, that the teeth in the front of the mouth point forward at an angle rather than straight up or down. Procumbent dentition allows the front tips of the jaws to be used to impale a fish, like a harpoon. Of course not all Piscivores have teeth. Piscivorous birds, like this loon, have fish-skewing beaks that are longy with sharp tips. A few carnivorous eat very hard food, and have specialized adaptations for cracking bones or shells. We call this kind of eating durophagy. Hyenas and Tasmanian Devils like this one here, have deep powerful jaws and thick rounded molars that allow them to crack bones. Many herbivorous mammals have teeth adapted for grinding plant material. The big horn sheep, dear and kangaroos all have flattened molars that create an excellent grinding surface. Like carnivores, herbivores have specialized feeding habits and adaptations, such as the fruit eaters or frugivores. There are also browsing herbivores like giraffe. And grazing herbivore's like this horse here. And you can see that its teeth provide an excellent grinding surface for plant material. Omnivores eat both plants and animals, and so they can have a mixture of dental adaptations. Warthogs, like this skull here, are a good example of a modern omnivore. You can see at the front, the incisors, which are for grasping prey or plants, as well as the tusks and the molars, which are for grinding plant material. Humans are also omnivores. You can feel in your own mouth the sharp tearing teeth of your canines and premolars, while your molars are relatively flat, and can be used for grinding plant material. Here are two skulls. Indicate below each drawing if the skull represents a carnivore or a herbivore. Looking at the first skull, we can easily see that it has flat, grinding teeth. And no real sharp curved teeth. This skull, which belonged to a horse, shows the classic signs of a herbivore. On the other hand, this lion skull with its sharp pointed teeth, shows a pattern that we would expect from a carnivore.
