Skull Teaching Guide
By
Joey Williams
Museum of Osteology
Director of Education
education@museumofosteology.org
Why Skulls?
So why do we study skulls? The simple answer is to learn more about the animals they came
from. However, there is a far better reason to encompass skulls in to learning...fascination. What
holds our fascination with these gems of nature? Is it the macabre? Is it our natural wonder of
death? Is it the innate attraction we all share for a mystery? To be honest, I’m not quite sure
where the fascination comes from, but one thing I do know is that nothing holds our attention
quite like a skull.
I personally became a skull “junkie” when I was only 10 years old. It was a typical weekend
spent wandering the Midwestern countryside with my best friend. Every weekend we would
partake in “adventures,” exploring the meadows, prairies, and woodlands found near his country
home. One day, as we wound our way through a tangled hedgerow, I came upon a packrat nest.
Packrats, as their name suggests, are notorious for collecting various items. They use these items
to help build or adorn their nests; woven piles of twigs, leaves and branches. In this particular
nest, an unusual object caught my eye. It was a complete jawbone. I picked up the bone and
examined it. I wondered what kind of creature it might be from. I noticed the sharp teeth and
slender shape. Just a few feet away from the nest lay the upper skull...too heavy for the packrat to
carry. I grabbed the skull and articulated the jaw with it. My mind began to imagine the animal
this skull belonged to. It took me some further research to determine the skull I had found was
from a coyote. It was this single skull that started my fascination. I collected many more skulls
over the years and eventually my interests led me to pursue a degree in biology and a career in
natural history education.
I have often used skulls as instructional objects when teaching various biological and
anatomical concepts. Skulls can be very useful when focusing on dietary habits, food chains,
predator/prey relationships, anatomy, biology, ecology, habitats, adaptation, evolution and animal
behavior...to name a few. My career revolves around using informal, hands-on learning to teach
key biological concepts. I have presented countless outreach programs, classes and teacher
workshops to a myriad of age groups. Every time I pull out a skull, the attention of my audience
quickly becomes cemented on the specimen. Immediately questions arise like: “What kind of
animal was that?”, “What did that animal eat?” and “How did it die?” I explain that all of these
questions, and more, can be answered if you know how to “read” a skull...and this guide will give
you some insight how to do just that.
This booklet is presented as a guide to educators who want to, or who already, use skulls as
teaching tools. Since learning varies between age groups and science standards differ from state
to state, I encourage you to take this information, refine it, and design your own lesson plans or
curriculum. You as the instructor will know best how to gauge your students and how to apply
this information.
I welcome your questions, feedback and ideas. Please do not hesitate to contact me at
education@museumofosteology.org or call 405-841-0006.
Joey Williams,
Director of Education
Museum of Osteology
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Table of Contents
Introduction: Why Skulls? ........................................................................................ 2
Table of Contents ........................................................................................................ 3
How to Read a Skull ..................................................................................................... 4
How to Read a Skull: Teeth ......................................................................................... 5
Carnivore, Herbivore, Omnivore.
How to Read a Skull: Eye Placement and Size .......................................................... 6
Nocturnal, Predator and Prey.
How to Read a Skull: Jaw Attachment ...................................................................... 6
Predator and Prey.
How to Read a Skull: Beaks ........................................................................................ 7
Bird Feeding Adaptations.
How to Read a Skull: Horns and Antlers ................................................................... 8
Defense, Communication, Breeding.
How to Read a Skull: Pathology ................................................................................. 8
Injury, Disease, Infection, Genetics.
How to Read a Skull: Age and Gender ...................................................................... 9
Tooth Wear, Molar Eruption, Suture Development, Sagital Crest.
Activities
Using a Dichotomous Key ................................................................................. 10
Using Teeth to Determine Diet ......................................................................... 10
Eye Placement: Predator vs. Prey .................................................................... 11
Eye Placement: Habitat ..................................................................................... 11
Nocturnal Vision ................................................................................................ 12
What Did This Bird Eat? .................................................................................. 12
Labeled Skull Diagrams .............................................................................................. 13
Glossary ..................................................................................................................... 14-15
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How to Read a Skull
Have you ever found a skull and wondered, "What kind of animal was this?" or,
"What did this animal eat?" or "How did this animal die?" Skulls can answer all of these
questions and more…if you know how to "read" them. Characteristics such as type of
teeth, eye placement, abnormalities, etc. can aid in interpreting information about the
animal’s life. As the pages of a book may be read to reveal a story, 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.
Many scientific professions rely on interpreting skulls and bones to tell a story.
Paleontologists and archaeologists must know how to read skulls and bones so they can
understand the past. Forensic pathologists, who investigate crime scenes, must also
know how to read skulls and bones to be able to establish the cause of death. The
following pages will provide you with some useful information and help you learn how to
read a skull.
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How to Read a Skull: Teeth
Perhaps the most obvious feature of an animal’s skull is its
teeth. Mammals, as well as most reptiles, amphibians and fish,
have teeth. An animal’s teeth can tell you a lot about its life.
The type of teeth it has, the shape of the teeth, and even the
number of teeth an animal possesses can help determine its
diet and lifestyle. If a mammal has long sharp canines, it is
most likely a predator. Canines are used for grabbing, holding
The bobcat is a carnivore.
and killing prey. Some meat eating mammals, called
carnivores, have sharp shearing cheek-teeth called carnassials.
With one carnassial located in the upper jaw and another on
the lower, these teeth act like a scissor to cut through tough
flesh. Carnassials also help to slice their meal into smaller
pieces for swallowing and digestion. Examples of carnivores
that possess long, sharp canines and shearing carnassials
include cats, dogs, hyenas and weasels.
Herbivores, or plant eating animals, have teeth designed
for chewing various plant parts. Some plant eaters, called
grazers, specialize in eating grasses, while other herbivores,
called browsers, eat twigs, leaves and berries. Still other
The beaver is an herbivore. herbivores eat only specific plant parts such as roots, fruit, etc.
In order to digest vegetation, an herbivore must thoroughly
chew its food. Chewing helps break down the rigid cell wall
found in plants. Most herbivores have cheek teeth, called
molars, specifically adapted for this purpose. These molars
help grind leaves, stems, grasses, fruit and even seeds before
the animal swallows them. Some examples of herbivorous
animals include deer, rabbits and cattle.
Omnivores are animals that eat both plants and animals.
Omnivores possess teeth with characteristics of carnivores and
herbivores. Omnivores are less specific about what they eat
The raccoon is an omnivore. and, therefore, tend to be more apt at survival. Omnivores
include pigs, bears and humans.
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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
Eyes positioned on the side of this depth perception to track and pursue prey. Cats and owls
a skull indicate a prey species.
are excellent examples of predators that use forward facing
eyes when hunting their prey. Monkeys 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.
Owls possess large eyes that This vision is very important for protecting an animal when it is
aid their nocturnal vision. grazing or feeding.
“Eyes in the front, the animal hunts. Eyes on the side, the animal hides.”
“Eyes in the front, the animal hunts.
Eyes on the side, the animal
hides.”
Predator Vision Prey Vision
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How to Read a Skull: Jaw Attachment
The way an animal’s jaw attaches to its
skull can help determine an animal’s diet. This can
also help determine whether the animal was
predator or prey. An animal that must chew its food
in a side-to-side motion must have a jaw attach-
ment that allows for these gliding movements. This
type of jaw attachment is found in herbivores (prey
Predator skull animals) and in some omnivores, such as humans.
A carnivore’s (predator) jaw attachment
works in an up and down motion. This, combined
with the shearing carnassial cheek teeth, makes
short work of the toughest hide and tissue. You can
use various skulls to explore these jaw
attachments further.
Prey skull
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.
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How to Read a Skull: Horns and Antlers
Horns or antlers found on a skull bear evidence of how
an animal communicated, defended itself and possibly the
animal’s sex. Animals can either 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
Pathology refers to abnormalities found in
the structure of a bone. These abnormalities can be
the result of previous injuries, disease, infection or
genetics. The pathology of a skull can tell you what
may have caused an animal’s death. These
pathologic conditions might tell you if the animal
was hit by a car, shot by a gun, died from a disease
or killed by another animal. Below are a few more
examples of pathological specimens including a
selection of postcranial bones. Each is compared A normal skunk skull compared with a
skunk skull exhibiting Skrjabingylus
with a normal bone to emphasize the pathology. nematode infection.
From left to right; Deer mandible with Actinomycosis (lumpy jaw), Diseased goat metatarsal, Domestic cat skull exhibiting severe bone degradation
Broken and healed baboon femur, Broken and healed coyote fibula/tibia. due to renal failure.
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How to Read a Skull: Age and Gender
Several skull features can be used to
help gauge the age of a specimen. Molar
eruption and tooth wear are two of the easiest to
notice. In most mammals, the last molar will not
erupt until maturity. If you know the species of
skull you have, and the deal formula for that
species, you can check to see if the last molar
has erupted. If it has, you have an adult...if not,
you have a juvenile. As an animal ages, teeth
can become worn and damaged. A young adult
will typically have a full compliment of teeth with
very little surface wear. The older an animal gets,
the more wear their teeth will exhibit. Very old
specimens may be missing all or most of their
Three deer jaws showing tooth wear due to age.
teeth, which could ultimately lead to the animal’s Top; Young adult deer, Middle; Average adult
death. deer, Bottom; Old adult deer.
Suture development is also an effective
means to gauging a specimen age at death.
When a mammal is first born, the skull is not yet
fully formed and is comprised of many individual
bones. This allows for passage through the birth
canal. As an animal grows and matures, the
individual plates of the skull grow together and
form connective sutures. As the animal continues
to age, these sutures become more solid until
they eventually fuse. If you have a skull, with
obvious sutures, your specimen is still growing. If
your skull is lacking sutures, you may have a
mature specimen.
A young raccoon skull, front with sutures
emphasized, compared to a mature raccoon,
rear, with fused sutures.
It is possible to identify a
specimen’s gender by specific skull
characteristics. However, this can be
difficult depending on the species, age of
the specimen and condition of the skull.
A general characteristic to look for in a
number of mammals is the sagital crest
development. Males of many mammal
species tend to have a more developed
sagital crest than the female. In some
species, the female lacks a crest all
together. However, this is not always the
case, so it important for you to know
A male bobcat (left) compared to a female bobcat (right) with what species you have before you
sagital crests emphasized.
attempt to identify its sex.
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Activities
As with many classroom science teachers, you probably have a few skulls lying around. The
following is a brief list of the type of skull activities you can do with students. Skulls Unlimited
International is the leading supplier of skulls and skeletons in the world. If you are looking for
additional natural bone or replica skulls, contact them at
www.skullsunlimited.com or 800-659-7585.
Using a Dichotomous Key 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. However, this can be less than
accurate and most people will not have access to a large collection of known species. The most
effective means of identifying a skull 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. Keying skulls can be
a fun and rewarding activity.
Using Teeth to Determine Diet
A very simple and fun activity for younger children is using mammal skulls to determine
an animal’s diet. This activity can help to cement national science standards and teach some of
the characteristics between carnivores, herbivores and omnivores. Using a variety of herbivore,
omnivore and carnivore skulls, have your students examine the teeth of each specimen. Ask your
students what purpose each tooth might serve. Point out that not all teeth are used for chewing.
Some, such as canines are used for grabbing and tearing. Ask the students to imagine what kind
of tools each too resembles (i.e. canine = knife, molar = grinder). Have the students hypothesize
what each animal ate. What kind of teeth do humans have...carnivore, herbivore, or omnivore?
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Activities
Eye Placement: Predator vs. Prey
Using a predator and a prey animal skull, have your students locate the orbit or eye
sockets of each species. Ask your students which one has eyes on the side of its head and which
has eyes in the front. Ask your students how the placement of eyes might help an animal see.
Ask them how this placement would affect the animal being a predator or prey animal.
Remember, “Eyes in the front, the animal hunts. Eyes on the side, the animal hides.”
Eye Placement: Habitat
Using a primate and a beaver or otter skull, have participants locate the orbit or eye
sockets of each species. Ask how an animal’s daily life could affect its eye placement. For
example, most tree dwelling primates have forward facing eyes. This type of eye placement is an
advantageous to their lifestyle by allowing them to better judge distance when leaping from tree to
tree. Beavers and sea otters, both semi-aquatic species, have eyes (and a nose) that sit high on
their heads, allowing them to see (and breathe) without exposing too much of their body above
the surface of the water.
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Activities
Nocturnal Vision
Using an owl skull, or other nocturnal species, have your students observe the large eye
sockets. Ask your students why the specimen would need such large eyes. Larger eyes allow for
more light absorbing rods, thus making it easier to see in low light conditions. An owl’s eye
sockets are surrounded by a bony ring called a sclerotic ossicle. This helps support their large
eyes. All raptors have excellent vision for hunting, but an owl’s vision is specifically adapted to
hunting at night.
Owl Skull Tarsier Skull
What Did This Bird Eat?
Using a variety of bird skulls, and without identifying the species of each skull, ask your
students to hypothesize as to what each species might eat. Encourage them to imagine the types
of food each beak style is best suited for. Help your students by pointing out the differences
between each beak, and how those differences might aid in eating.
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Bobcat skull, dorsal view. Beaver skull, dorsal view.
Bobcat skull, lateral view. Beaver skull, lateral view.
Bobcat skull, ventral view. Beaver skull, ventral view.
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Glossary/Vocabulary Words
Adaptation: Any modification made or developed to assist in the survival of a species.
Amphibia: The taxonomic class to which all amphibians belong. This class includes all frogs, toads, salamanders, newts and
caecilians.
Amphibian: An animal that is ectothermic with smooth and sometimes slimy skin. Amphibians lay non-shelled egg clusters in the
water. Most amphibians begin their life as a gill breathing aquatic larval form and later morph into a lung breathing adult form. All
amphibians belong to the class Amphibia.
Antler: A horn-like, generally multi-pronged, projection that grows from the head of male members of the deer family Cervidae.
Antlers are grown annually, mainly to help establish dominance during the mating season, and then are shed.
Aquatic: Referring to a species that lives in the water.
Arboreal: Referring to a species that lives in trees.
Auditory Bulla: Bulbous projection, usually on the under side of a skull, used to house the ear drum and small bones used in hearing.
Plural = Bullae.
Aves: The taxonomic class to which all birds belong.
Binocular Vision: Vision in which an animal can focus on an object with both eyes. Synonymous with Stereoscopic Vision.
Bird: An animal that is endothermic, possesses feathers, and lays hard-shelled eggs. Most birds, although not all, possess limbs that
are modified for flight. All birds belong to the class Aves.
Browser: An animal that eats a combination of leaves, bark and saplings, but generally does not eat grasses. Typically a woodland
species.
Canine: The long, sharp grasping teeth found in carnivores and most omnivores. Canine teeth are sometimes wrongly called “fangs.”
Carnassial: The sharp-edged cheek teeth that act like a scissor when chewing flesh. Carnassial teeth are found in mammals
belonging to the order Carnivora which includes all dogs, cats, weasels and bears.
Carnivore: Any animal with a diet consisting mainly of animal meat.
Carrion: A dead animal or decomposing carcass.
Crepuscular: Active during the early morning as well as in the evening.
Condyle: A surface where two bones attach that is usually convex or concave in shape.
Diurnal: Active during the day.
Ectothermic: An animal with a body temperature that varies depending on its external temperature. A species that does not maintain
a constant body temperature. Synonymous with Poikilothermic or “Cold-blooded”. Insects, fish, amphibians and reptiles are examples
of ectothermic animals.
Endothermic: The ability to maintain a constant body temperature. Synonymous with Homoeothermic or “Warm-blooded”. Birds
and mammals are examples of animals that are endothermic.
Fitness: A natural organisms ability to live, survive and reproduce.
Foramen Magnum: Large natural opening located on the posterior side of a skull where the spinal cord attaches to the brain.
Frontal: The bone that makes up the “Fore Head”.
Grazer: An animal that primarily eats grasses. Typically a prairie or plains species.
Habitat: A specific environment in which a species lives.
Herbivore: Any animal with a diet consisting mainly of plant vegetation.
Homoeothermic: The ability to maintain a constant body temperature. Synonymous with Endothermic or “Warm-blooded”. Birds
and mammals are examples of animals that are homoeothermic.
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Glossary/Vocabulary Words
Horn: An ever-growing, keratin covered, boney projection that grows from the head of members of the Bovidae family including
cattle, goats, sheep, gazelle and antelope. Depending on the species, horns can be found in both males and females.
Hypothesis: An idea formed to be tested and proven or dis-proven.
Incisor: Front teeth that are typically used for chomping or stripping hair from prey and vegetation from plants.
Keratin: The substance that horns, hair and finger nails are composed of.
Mammal: An animal that is endothermic, possesses fur or hair, and is capable of feeding its young with milk from specialized
mammary glands. Most mammal species are capable of live birth, although there are three mammal species that lay eggs. All
mammals belong to the class Mammalia.
Mammalia: The taxonomic class to which all mammals belong.
Mandible: The jaw bone.
Maxilla: The upper jaw, usually where the upper teeth root.
Molar: Cheek teeth that are typically used for grinding or chewing.
Nasal: The delicate bones that comprise the bridge of the nose and help protect the nasal passage.
Nocturnal: Active at night.
Occipital Condyle: The area where the skull attaches to the atlas vertebrae. A condyle located on the occipital bone of the skull.
Omnivore: Any animal with a diet consisting of both animal meat and plant vegetation.
Orbit: The eye socket or area where the eye sits in a skull.
Palatine: The hard roof of the mouth, also called the Palate.
Pathology: Damage as a result from injury or disease.
Poikilothermic: An animal with a body temperature that varies depending on its external temperature. A species that does not
maintain a constant body temperature. Synonymous with Ectothermic or “Cold-blooded”. Insects, fish, amphibians and reptiles are
examples of poikilothermic animals.
Predator: An animal that hunts other animals as a food source.
Premaxilla: Bones that make up the anterior tip of the upper jaw. “Lip bones”.
Prey: An animal, typically an herbivore, that is a source of food for other animals.
Process: A boney projection from the skull. Infraorbital process = a boney projection(process) located above(infra) the eye
socket(orbital).
Raptor: A synonym for any bird of prey. Hawks, owls, eagles and falcons are examples of raptors.
Reptile: An animal that is ectothermic, possesses a scaly, dry skin and lays soft-shelled eggs. All reptiles belong to the class Reptilia.
Reptilia: The taxonomic class to which all reptiles belong. This class commonly includes all snakes, lizards, crocodiles, turtles and
the tuatara.
Scavenger: A species which feeds on prey that it has not killed. An animal that eats other animals leftovers.
Stereoscopic Vision: Vision in which an animal can focus on an object with both eyes. Synonymous with Binocular Vision.
Talon: The long, sharp toe nail of a bird of prey. Used for grabbing and killing prey.
Vertebrate: Any animal that possesses a boney vertebral column. An animal that has a backbone.
Zygomatic Arch: The cheek bone.
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