Skull Sleuthing – Activities

FOCUS: The shape and structure of skull and teeth are adaptations related to an animal’s food and way of life. The teeth and eye placement of carnivores differ from those of herbivores, omnivores, or insectivores. Much can be learned about an animal from its skull, for these are the bones that protect the brain and house the mouth, teeth, and sense organs – all of which are critical to its survival.

INTRODUCTION
Objective: To begin to explore and ask questions about skulls.

Give each small group of children a skull to examine. Ask children to draw their skull, and to write down one thing they notice and one thing they wonder about it.

Materials: Skulls Set, magnifying lenses, paper or journals, pencils.

TOOTHY GRINS
Objective: To observe our four different kinds of teeth and investigate how we use them.

Have children smile at each other and notice each other’s teeth.

Notice that some are flat-topped and some come to a point. Some have one point and some have several points. Some are narrow and some are broad. Now have children feel their own teeth as you show them a dental cast or diagram and point out the incisors, canines, premolars, and molars. Ask why we might have different kinds of teeth. How could we find out what the different teeth are for? One way would be to try eating different kinds of foods.

Pass out a napkin to each child and some popcorn, a carrot stick, and a piece of chewy dried fruit. Tell the children to wait for instructions before eating anything. Have them pick up the piece of popcorn first. At the count of three they must pop the popcorn into their mouths and chew it up. Ask which teeth they used to chew up the popcorn. (Molars.) These are “grinders,” needed for grinding up tough food.

Next instruct children to bite off a piece of carrot and chew it up. Which teeth did most children use to bite off the carrot piece? (Incisors.) These are used as “clippers” or “nippers,” for biting off hard foods.

Finally have children bite off a piece of the chewy dried fruit. Which teeth did they use? (Canines and/or premolars.) These are used as “rippers” and are important for tearing and eating meat.

Notice how our upper teeth work together with our lower teeth. What makes our jaw operate? Have children feel their cheekbones and temples while chewing to feel the jaw muscles working.

Materials: napkins, popcorn, carrot sticks, chewy dried fruit such as pears, mango; optional: plaster cast of human teeth.

DENTAL DETECTIVES
Objective: To notice some basic differences in the dentition of a carnivore, herbivore, omnivore, and insectivore.

Display large-size line drawings of generalized skulls (Skull Silhouettes) showing the teeth in a side view. Cover the labels identifying the animal and food-type with index cards or sticky-notes. Include the following five different types of skulls:

Carnivore (e.g. bobcat)

Insectivore (e.g. shrew or mole)

Omnivore (e.g. raccoon or bear)

Gnawing Herbivore (e.g. beaver)

Grazing Herbivore (e.g. deer)

In a separate location, list these five possibilities and ask the children to help you match the labels with the skull drawings. What kind of teeth would a gnawing mammal like a beaver need to have? (Chisel-like incisors and flat, grinding molars.) Ask students to pick out the grazing herbivore (ruminant) which lacks upper incisors, canines, and premolars. What kinds of teeth would an insectivore need? (Sharp needle-like teeth to pierce their hard-shelled insect prey.) What kind of teeth would a carnivore have (pointy canines, sharp molars and premolars) and how would an omnivore differ? (Both sharp canines and premolars for tearing meat and broad molars for grinding vegetation.) Notice that human teeth are very uniform compared to animals’ teeth as we are generalists, eating a variety of mostly soft foods.

Materials: Skull Silhouettes, tape, white board and dry-erase marker or chalkboard and chalk, sticky-notes or index cards.

MYSTERY SKULLS
Objective: To learn the parts of a skull and use observations and measurements to identify a variety of animal skulls.

Set out skulls at several different stations. Divide up the class, assigning each group to a different skull. Begin by having the children feel some of these different parts on their own heads and look at them on their animal skull.

Cranium (brain case)

Upper jaw (part of the skull)

Lower jaw (separate from the skull)

Eye sockets

Cheek bone (under the eye sockets)

Nose bones

Teeth

Ear canals and ear bulbs

The large opening for the spinal cord at the back of the skull

*For 5th and 6th graders, use the scientific terms shown below in the Upper Grades challenge.

Why might skulls seem small compared to the size of the animal itself? (On a living animal the skull is covered with layers of muscles, skin, and fur.) Look at the teeth and compare to the skull silhouettes. Can they guess what kind of diet their animal might have had?

Have students rotate through all the stations, taking a few minutes to look at each of the skulls, until they are back at their first station. Now ask each team to investigate the skull at their station using the Mystery Skull Data Card below. Have teams compare the information they collect to the Skull Chart to help identify their skull. Provide a list of possible animals from which children can select the one they think matches their skull.

MYSTERY SKULL DATA CARD

Measure the length of the skull. How long is it? ___________inches.

Do the eyes seem to point toward the front like predators? ___ or toward the side like prey? ____ or is it too hard to tell? ____

Does the nose (snout) seem long like a dog’s or short like a cat’s? _________

Count the teeth in the upper jaw. How many does it have of each kind:

Incisors? ______ Canines? ______ Molars and Premolars? ______

Count the teeth in the lower jaw. How many does it have of each kind:

Incisors? ______ Canines? ______ Molars and Premolars? ______

What are the molars like? Are they all about the same or are there different kinds?

What special feature(s) do you notice about this skull? ________________________________

Looking at the teeth and comparing to the silhouettes, do you think the skull is that of a carnivore (meat-eater), herbivore (plant-eater), insectivore (insect-eater), or omnivore (eater of many foods)?  What makes you think so?

Compare your results (length, teeth count, diet, special features) to the chart.

What animal do you think this is? _______________________ Why do you think so?

*Note that skulls look smaller than you’d expect when the muscles, skin and fur are gone.

Materials: five or six skulls of different animals, Mystery Skull Data Cards, Skull Charts, rulers, clipboards, pencils.

UPPER GRADES CHALLENGE: Parts of the Skull (Grades 5-6)
Objective: To become familiar with some of the parts of a vertebrate skull and learn their scientific names.

Give each team of students a Parts of a Skull sheet with numbered arrows pointing to its basic features. Provide students with the following list of names and descriptions for each of these parts. Have the students study the descriptions and try to identify each of the structures in the skull diagram and on an actual skull.

Cranium = the brain case

Foramen Magnum = the large opening at the back of the brain case for the spinal cord

Sagittal Crest = the ridge on the midline of the brain case for jaw muscle attachment

Occipital Crest = the cross-ways ridge on the back of the brain case for jaw muscle attachment Orbit = the eye socket

Zygomatic Arch = the cheek bone, under the eye sockets

Infraorbital foramen = the small hole in front of the eye socket for the face nerves

Mandible = the lower jaw, a separate piece from the rest of the skull

Maxilla = the upper jaw, attached to the skull

Nasal bone = the bone above the nose opening

Ear bulb = the ball-like projection on the underside of the brain case

Ear canal = the hole in the ear bulb

Afterwards review the parts of the skull and correct any mistakes. Looking at the skull diagram, ask the students if the animal is a carnivore, herbivore, or omnivore.

Key: 1=Cranium; 2=Foramen Magnum; 3=Sagittal Crest; 4=Occipital Crest;5=Orbit; 6=Zygomatic Arch; 7=Infraorbital foramen; 8=Mandible; 9=Maxilla; 10=Nasal bone; 11=Ear bulb; 12=Ear Canal; Black Bear: omnivore.

Materials: for each team of students: Parts of a Skull sheet, pencils; optional: a real skull.

CHEZ FOUR WINDS
Objective: To write an imaginative menu for an animal based on knowledge of its diet.

Based on the Skull Investigation, have each team guess which animal’s skull they have and whisper their guess to the adult leader. Give each team an Animal Information card showing a photo of the animal they identified in the Mystery Skulls activity above and a list of the kinds of food it eats. Provide a blank Menu Template and have the children make up an appetizer, entrée, dessert and beverage for their animal (and a name for the restaurant if time permits). Taking turns, have teams tell one special thing they noticed about their skulls and read their menus out loud. Have classmates guess which animal might like to eat at this restaurant.

Materials: Animal Information cards; Menu Templates, one per team; clipboards, pencils.

PUPPET SHOW “Dinner Guest Dilemmas”
Objective: To discover the connection between teeth and diet in carnivores, herbivores, insectivores and omnivores.

Perform the puppet show or have the children perform it for their classmates. Afterward, ask questions to review the key details and vocabulary in the story. What is an herbivore (plant-eater), carnivore (meat-eater), and omnivore (eats both plants and animals)? Which character was an herbivore (squirrel), a carnivore (weasel), and an omnivore (bear)? Which character was an insectivore (mole) and what does it eat (mostly insects)?

Materials: puppets, script, props, stage.

JAWFUL BEASTS and JOURNAL ACTIVITY
Objective: To design an imaginary creature with teeth suited to its particular diet and write about it as a journal entry.

Provide children with a hinged paper plate or cardboard skull and jaw, or Skull and Jaw Template, and ask them to make up an imaginary creature and decide what it would like to eat. Have them make teeth out of paper or clay or draw their critter’s teeth on the outline. In their journals have children describe their Jawful Beast’s diet and how its teeth help it to eat this kind of food. Be sure to have them give the creature a name. In small groups, have children introduce their Jawful Beast and tell how its teeth are adapted for eating its preferred food. Have others guess whether it is a carnivore, omnivore, herbivore, or insectivore.

Materials: skull and jaw pattern; cardboard or paper plate jaws made with paper fasteners, modeling clay (walnut-sized piece for each child); or Skull and Jaw Template, one copy for each child, and pencils, crayons, or colored pencils; journals.

CLOSING THOUGHTS
Objective: To share some thoughts and observations about skulls.

Have children complete this sentence: “My favorite thing about skulls is ________________.”

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