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Animal Hair. Why is animal hair important Evidence shows animal hair present— victim does not own a dog, could infer suspect owns a dog or has come in.

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Presentation on theme: "Animal Hair. Why is animal hair important Evidence shows animal hair present— victim does not own a dog, could infer suspect owns a dog or has come in."— Presentation transcript:

1 Animal Hair

2 Why is animal hair important Evidence shows animal hair present— victim does not own a dog, could infer suspect owns a dog or has come in contact with a dog. DNA could be removed from animal’s mouth (if bitten) Blood samples could be removed from animals fur, feet, etc.

3 Two Types Wool Hairs==tin, soft, kinked and not straight found close to the skin Guard Hairs—longer, thicker, straight and make up the hairs typically seen on the back of the animal

4 Human or Animal? With hair identification, it can first be determined whether a hair is human (Fig. 1) or animal (Fig. 2): The following are some of the distinguishing features. Length: Human scalp hairs are longer than most animal hairs. Diameter: Human hairs are usually in the range of 0.05-0.15 mm; animal hairs can be narrower or coarser

5 Human vs Animal Color: Animal hair can have a banded appearance; untreated human hair never does. Treatment: Except when used in textile materials, animal hair rarely exhibits dying, bleaching or other cosmetic treatment. Medulla: Animal hairs can have a complex regular/ geometric cellular medulla; human hairs have only an amorphous medullary structure. Medullary index: Defined as the ratio of the diameter of the medulla to the diameter of the hair, the medullary index in human hair is almost always less than 1/3; in animal hair it is usually greater than 1/3. Pigment distribution: Animal hairs can have pigment distributed about the medulla whereas this is extremely rare in humans

6 Human vs Animal hair Shaft: Animal hairs can have different shapes than human, e.g. the spatulate shape found in rodent hairs. Root: Animal hairs have different root shapes, typically brush-like, whereas humans’ are bulb or ribbon- shaped. Tip: Human hair (particularly scalp) is usually cut or frayed at the tip; animal hair is generally naturally tapered. Scales: Human hair only exhibits irregular annular scale patterns; animal hair has a variety of types and can have more than one type in the same hair. Cross-section: Animal hairs can have some unusual shapes, e.g. dog bone (rabbit) and cigar shaped (seal).

7 Animal Hairs Human Cat Dog Mouse

8 Animal Hairs animal hairs do not possess enough individual microscopic characteristics to be associated with a particular animal to the exclusion of other similar animals If the questioned hair exhibits the same microscopic characteristics as the known hairs, it is concluded that the hair is consistent with originating from that animal

9 Horse Hair bsapp.com

10 Dog Hair bsapp.com

11 Cat Hair bsapp.com

12 Mouse Hair bsapp.com

13 Rabbit Hair bsapp.com

14 Deer Hair bsapp.com

15 Pig Hair bsapp.com

16 Cow Hair bsapp.com


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