Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
1 What Can Skulls Tell Us? Have you ever found a skull in the woods and wondered, "What kind of animal was this?" or, "I wonder what this animal ate?" or "How did this animal die?" Skulls can answer all of these questions…if you know how to "read" them. Like the pages of a book may be read to reveal the life of a man, so may a skull be "read" to reveal the history and lifestyle of an animal. If you know what to look for, you can interpret information about how the animal lived its life and possibly, even how it died. How to "read" a skull: Teeth Mammals, as well as some reptiles, amphibians and fish, have teeth. The teeth of an animal can tell you a lot about that animal's life. The type, shape and number of teeth an animal has can help determine its diet. If a mammal has long, sharp canines, it was most likely a predator. Canines are used for grabbing, holding and killing prey. Some meat-eating mammals (carnivores) have sharp shearing cheek-teeth called carnassials. These teeth act like a scissor to cut through tough flesh and to break it into smaller pieces for swallowing and digestion. Examples of carnivores include cats, dogs and weasels. Plant eating animals tend to have teeth specialized in chewing various parts of plants. Some plant eaters eat grasses (grazers), some eat twigs, leaves and berries (browsers) while others eat only specific plant parts (I.e. roots, fruit, etc.). In order to properly digest vegetation, an animal must chew its food to help break down the plant. Most herbivores have cheek teeth called molars. These molars help grind leaves, stems, grasses, fruit and even seeds before the animal swallows them. Examples of herbivores include deer, giraffe and cattle. Some animals eat both plants and animals (omnivores) and have both types of teeth. Examples of omnivores include pigs, bears and humans. Rolling Hills Wildlife Adventure 2 How to "read" a skull: Beaks The beak of a bird is an extension of its skull and is designed for feeding. Some beaks have evolved to specialize in feeding specific items. A duck, hawk, hummingbird and sparrow are all birds, but their beaks are very different due to their different diet. A duck has a wide flattened "bill" used for eating aquatic plants and mosses. A hawk has a sharp hooked beak used in tearing flesh from its prey or carrion. A hummingbird uses its long narrow beak to lap nectar from flowers and a sparrow has a small powerful beak used for picking berries and cracking seeds. As you can see, a bird's beak can tell you a lot about not only the diet, but also the lifestyle of its owner. How to "read" a skull: Eye Placement and Size What do the eye sockets of a skull tell you about an animal? A lot! Eye sockets that are large in relation to the size of an animal's skull may suggest an animal is active at night (nocturnal). In this case, a larger eye has evolved to allow the animal to see better at night. Eyes that face forward on a skull suggest a predator. Forward facing eyes allow for binocular or stereoscopic vision, which allows an animal to see and judge depth. Predators need this depth perception to track and pursue prey. Cats and owls are excellent examples of predators that use forward facing eyes when hunting their prey. Monkeys & Apes also have forward facing eyes that give them depth perception needed to swing and leap in their tree top habitat. Humans have forward facing eyes as well. Animals with eyes that are located on the side of its head would suggest a prey animal. Side eye placement allows for greater peripheral or side vision. This enables the animal to see predators approaching from the side as well as from behind. This vision is very important for protecting an animal when it is grazing or feeding. "Eyes in the front, the animal hunts. Eyes on the side, the animal hides." Rolling Hills Wildlife Adventure 3 How to "read" a skull: Horns and Antlers Horns or antlers found on a skull bear evidence of how an animal communicated, defended it's self and possibly the animals sex. Animals can protect themselves or attack other animals by goring them with their horns or antlers. Bighorn sheep, muskox and deer use their horns or antlers for establishing territory and winning mates. What is the difference between horns and antlers? Horns are permanent structures that grow year after year. Depending on the species, both male and female bovid animals (cattle, gazelle, antelope, etc.) can have horns. Antlers, however, are temporary. Antlers grow, develop and shed from the animal once a year. Antlers are branched and only found in the cervid family (deer, moose, elk, etc.). With the exception of the female caribou, only male cervids have antlers. How to "read" a skull: Pathology The pathology of a skull can tell you what may have caused an animals death. Pathology is damage that may be the result of trauma, disease or infection. These pathologic conditions might tell you if the animal was hit buy a car, shot by a gun, died from a disease or was killed by another animal. How to Identify a Skull: When using skulls in education, the first question usually asked is "What kind of skull is that"? Skull identification can be determined by several methods. If you are unsure of a skull's identification, you can compare it with other known specimens. This, however, can be less than accurate and most will not have access to a large collection of known species. The most effective means of identifying a skull to species is with the use of a dichotomous key. A dichotomous key allows a person, through a series of questions, to identify an organism to species by process of elimination. Plants, fish and even skulls can be identified using this method. Rolling Hills Wildlife Adventure 4 Below are images of typical carnivore (bobcat), omnivore (raccoon) and herbivore (beaver) skulls. Various parts of each skull have been labeled to aid in comparative anatomy. These images may also prove to be useful in locating skull parts for dichotomous key identification. Bobcat Skull Raccoon Skull www.skullsunlimited.com/graphics Rolling Hills Wildlife Adventure Beaver Skull