Forensic ScienceForensic Science

Hair Evidence: Animal vs. HumanHair Evidence: Animal vs. Human

Hair EvidenceHair Evidence

Many class characteristics can be determined; these characteristics can be used to eliminate suspects.

Forensic scientists can determine whether the hair was forcibly removed, damaged by burning, or artificially treated by dyeing or bleaching.

The region of the body where a hair originated can be determined with considerable accuracy by its macroscopic and microscopic characteristics.

In certain instances, a person’s race can be deduced from the hair.

Many class characteristics can be determined; these characteristics can be used to eliminate suspects.

Forensic scientists can determine whether the hair was forcibly removed, damaged by burning, or artificially treated by dyeing or bleaching.

The region of the body where a hair originated can be determined with considerable accuracy by its macroscopic and microscopic characteristics.

In certain instances, a person’s race can be deduced from the hair.

Types of Human HairTypes of Human Hair

Head hair Pubic hair Underarm hair Beard/mustache

hair Eyebrow/eyelash General body hair

Head hair Pubic hair Underarm hair Beard/mustache

hair Eyebrow/eyelash General body hair

Certain features of individual

hairs identify the region of

the body where it

originated.

Certain features of individual

hairs identify the region of

the body where it

originated.

Where is this Hair from?Where is this Hair from?

Where is this hair from?Where is this hair from?

Where is this hair from?Where is this hair from?

What is this?What is this?

Head hairs and pubic hairs exhibit a greater range of

microscopic characteristics than other human hairs;

therefore, head and pubic hairs are routinely forensically

compared.

Head hairs and pubic hairs exhibit a greater range of

microscopic characteristics than other human hairs;

therefore, head and pubic hairs are routinely forensically

compared.

Hair Characteristics: RaceHair Characteristics: Race Human hairs can be classified by racial origin

such as: Caucasian (European origin) African-American (African origin) Mongoloid (Asian origin).

In some instances, the racial characteristics exhibited are not clearly defined, indicating the hair may be of mixed-racial origin.

Racial indicators apply primarily to head hairs.

Human hairs can be classified by racial origin such as: Caucasian (European origin) African-American (African origin) Mongoloid (Asian origin).

In some instances, the racial characteristics exhibited are not clearly defined, indicating the hair may be of mixed-racial origin.

Racial indicators apply primarily to head hairs.

Caucasian

African-American

Mongoloid

Caucasian

African-American

Mongoloid

Human vs. Animal HairHuman vs. Animal Hair

How do you tell the difference?

How do you tell the difference?

Animal vs. Human Hair:Color

Animal vs. Human Hair:Color

Human hairs are generally consistent in color and pigmentation throughout the length of the hair shaft, whereas animal hairs may exhibit radical color changes in a short distance, called banding.

Human hairs are generally consistent in color and pigmentation throughout the length of the hair shaft, whereas animal hairs may exhibit radical color changes in a short distance, called banding.

Human vs. Animal Hair: Medullary Index

Human vs. Animal Hair: Medullary Index

The medulla, when present in human hairs, is generally less than one-third the overall diameter of the hair shaft. (MI = ??)

The medulla in animal hairs is normally continuous or interrupted, and it generally occupies an area of greater than one-half the overall diameter of the hair shaft. (MI = ??)

The medulla, when present in human hairs, is generally less than one-third the overall diameter of the hair shaft. (MI = ??)

The medulla in animal hairs is normally continuous or interrupted, and it generally occupies an area of greater than one-half the overall diameter of the hair shaft. (MI = ??)

Human hair is imbricate (flattened) Animal hair varies by species, but

can be spinuous or coronal, as well as imbricate

Human hair is imbricate (flattened) Animal hair varies by species, but

can be spinuous or coronal, as well as imbricate

Human vs. Animal Hair: Cuticle

Human vs. Animal Hair: Cuticle

Human vs. Animal Hair:Tip

Human vs. Animal Hair:Tip

Scissor cut or razor cut implies the hair has been “groomed”. Many animals are not groomed so if you see a scissor cut tip or a razor cut tip it might be a clue that the type of hair you are looking at did not come from an animal.

Scissor cut or razor cut implies the hair has been “groomed”. Many animals are not groomed so if you see a scissor cut tip or a razor cut tip it might be a clue that the type of hair you are looking at did not come from an animal.

Do “Explore” Page 17

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