Guard Hairs of Pennsylvania’s
Mammals: A Pictorial Atlas and
Identification Key
Megan R. Butts and Dr. Carlos A. Iudica
Biology Department - Susquehanna University
November 16, 2012
Purpose of the Research
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Obtain hair from collections and donations
Create casts of guard hairs to observe scale patterns within
the proximal, medial, and distal regions
Photograph scale patterns for each hair in the three regions
Photograph medulla’s patterns
Create an interactive (web-based) dichotomous key to
identify mammal hair from an unknown
Why Use Hairs?
Hair is the only identifiable structure
which retains its full characteristics after
digestion (other identifiable remains, such
as teeth or bones, may not be present,
partially digested, or too fragmented)
 Easy to obtain
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Basic Elements of a Hair
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Outgrowth of the epidermis;
forms the coat of mammals
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Is made of…
◦ Keratin
◦ Melanin
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…in three layers
◦ Cuticle, cortex, and medulla
© Stella Luca
© Stella Luca
Types of Hairs Found on Mammals
Guard Hair
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Only mammals have true hair
which covers the entire body
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Different types of hairs on
mammals
◦ Guard hairs and fine hairs
Fine Hair
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Why examine guard hairs vs.
fine hairs?
Distal
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On the hair shaft we identify
three different regions
◦ Proximal, medial, and
distal regions
Proximal
Medial
Cuticle Scale Patterns
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The cuticle of the hair contains the scales that we used to identify mammals
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Scale patterns differ in shape and size
Coronal Scales
Imbricate Scales
© Deedrick and Koch
© Deedrick and Koch
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Spinous Scales
© Deedrick and Koch
Guard hair patterns differ not only between species but also within the hair’s regions
Proximal
Medial
Distal
Medulla Patterns
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Medulla is the innermost central core of cells and is
surrounded by the cortex and cuticle
We identified nine medulla patterns
◦ Absent, discontinuous, globular, continuous, fragmental, lattice,
ladder, branched, and aeroform
Uniserial ladder pattern of mink hair
Hair Collection
Collected
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From dead animals on the side of the
road
From local animal
hospitals/shelters/breeders
Donated
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Local trappers
Reading Public Museum
State Museum of Pennsylvania in
Harrisburg
Labeled glassine envelopes and Ziploc
sandwich bags
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Important for the hairs to be separated
and relatively undamaged
Medulla Slide Preparation
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Wet mount
Light microscope (10X and/or 40X)
Lighting
Preparation of Cuticle Casts
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Clear nail polish
Set to dry (10 – 15 minutes)
Set hair on top
Another slide on top
(sandwich)
Sandwiched slides pressed for
10 minutes
Casts viewed under
microscope (10X or 40X) to
identify/catalog pattern
Viewing Hair Casts and Medulla Slides Under the
Microscope to Photograph Results and Compile a
Reference Collection
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We used a Zeiss Primo Star ®
Microscope connected to a Nikon
D90 (controlling with Nikon
Camera Control Pro 2)
Hair photographed using live view
mode
Pictures retouched with Adobe
Photoshop CS6 Extended 13.0 and
Adobe Lightroom 4.2
Creating a Pictorial Atlas
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Background information
◦ Order, Family, Scientific Name, Common Name
◦ Habitat/ecology
◦ General Information
Photos of species, medulla, and hair casts
 Specific information about medulla and scale
patterns
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Example Pictorial Atlas
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Order: Artiodactyla
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Family: Bovidae
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Scientific Name: Bison bison (Linnaeus, 1758)
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Common Name: Bison, American Bison, Buffalo
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Habitat: Live in many types of regions. These regions include open plains, grasslands, woodlands, openings in northern forests,
meadows, river valleys and semi-dry deserts. Like other large grazers, they are attracted to burned areas the next growing season
(Shaw and Carter 1990). In fall and winter, they grazed both burned and unburned watersheds more uniformly, but grazed most
intensively in areas with large stands of cool-season, C3 grasses (Vinton et al. 1993). They are also found in the mid-United States and
the Rocky Mountains.
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General Information
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© Jiri Bohdal
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Bison have a winter coat and a summer coat. The winter coat is shaggy and dark brown. The summer coat is lighter in weight
and light brown in color. The young bison, called calves, have a reddish-brown coat (Griffin and Johnson 1994).
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The hair on the adult bison’s head is much longer than the rest of the coat. This portion is called a mantle and is usually black in
color (Griffin and Johnson 1994).
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On very rare occasions, the coat of an individual is white. This type of bison is not albino since it still has pigmentation in the
skin, hair and eyes. Due to the rarity of this type of coat, the white bison, as they were called, were considered to be sacred to
the Native Americans.
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The hair samples used for research in this book were taken from the winter coat of a normal colored bison. The hair itself was
dark brown and very curly. Due to the dark brown coloring, these hairs were most likely taken from the back of the bison, not
the head.
Scale and Medulla Patterns
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The scale pattern of the bison has partially complete scale edges, although it seems to be non-coronal. The few complete scales
that are present form jagged, pointed ovals and half, jagged pointed ovals. The other complete edges go across the hair.
Proximal
Region
Medulla Pattern
Medial
Region
Distal Region
© Feretic
Dichotomous Key
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Photos used as visual within the
key
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Information used in identification
◦ Scale Patterns
 Coronal, imbricate, or spinous
◦ Regions of hair
 Proximal, medial, or distal
◦ Medulla Patterns
 Absent, discontinuous, globular,
continuous, fragmental, lattice,
ladder, branched, and aeroform
Spinous
Example of Dichotomous Key
0. Can pattern be easily seen?
Yes (Go to 1)
No (Hair belongs to Soricidae- Sorex palustris; Go to page xx)
1. Is there overlap?
Little to no overlap (Go to 2)
Overlap (Go to 14)
2. Is it coronal or non-coronal?
Coronal (Go to 3)
Non-coronal (Go to 11)
3. What shapes are the coronal scale?
Cone-shape (Go to 4)
Di-scale (Go to 7)
4. Do the top of the cone-shape, coronal scale have bumps?
Yes (Go to 5)
No (Go to 6)
5…and so forth
© Feretic
Launching a Website
The main goal is to create an open-access
website with an interactive dichotomous key
 Additional photos help visualize the
characteristics of each hair and navigate through
the key
 Could be used in databases such as the
Susquehanna University Library
 Launched through a site to be determined by
the Susquehanna IT Department
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What Happens Next?
Finish slide casts of all hairs, record all
specimens, and Photoshop/Lightroom
photographs
 Revise dichotomous key to include three
regions of each hair and medulla patterns
 Prepare material to be launched as an
informational website
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