There are distinct differences between human and animal hairs. This lesson will list the characteristics of human versus animal hair and explain how to differentiate one from the other by reviewing unique identifiers of each.
A Murder Mystery
Detective Stone is called in on a murder case that appears to be a real mystery. A woman's body was discovered on the side of the road. There is no identification on or near the body, so the woman's identity remains unknown. Her body is transported to the coroner's office where an autopsy and forensic investigation are completed. The forensics team notifies Detective Stone that several foreign hairs were found on the victim's clothing, and that the team is in the process of determining if the hair is human or came from an animal. Detective Stone wonders, 'Could forensic hair evidence could be the key to solving this case?'
In criminal investigations, hair evidence, or hairs discovered at or near the scene of a crime, can be an important clue in solving a case. Whether animal or human, hair has been key in solving important cases. Let's look at two case examples solved by hair.
In late 1977, the body of James Anagnos was found stabbed to death in the bar where he worked. Inside his fist, investigators found several strands of human hair. At the time, the field of forensic science was relatively new, and investigators were unable to match the hair to a key suspect in the case. The crime went unsolved until, in 2010, the preserved hair was sent to a forensic lab for analysis. Advanced forensic testing positively identified that the hair belonged to key suspect Frank Wright. Unfortunately, Wright was never prosecuted, since he passed away in 2002.
In 1998, the body of Elizabeth Ballard was discovered in a remote area of a New Mexico desert. There were relatively few clues available to help solve her murder, with the exception of some hairs that were found on one of the socks she was wearing. After a careful forensic examination, it was determined that the hair belonged to a dog. An exhaustive investigation was launched and the hair was eventually matched to a dog owned by one of the prime suspects in the case, resulting in the conviction of him and an associate.
Human or Animal Hair?
As evidenced in the cases above, both human and animal hair can be strong evidence in criminal cases. But how do forensic examiners distinguish one from the other? There are certain characteristics linked to each that forensic examiners are trained to look for.
According to forensic investigators, both human and animal hair can tell a story. It can tell investigators things like what someone or something ate, whether hair was chemically altered, and what part of the country was most recently visited. Human hair, however, has some unique characteristics. The color and pigmentation of human hair, for example, tends to be even and consistent throughout the entire hair strand.
It would be extremely unusual to find a human hair that is brown at the bottom, turns blonde in the middle, and black towards the root, unless of course it was artificially altered. Instead, an identifying characteristic of humans is the color of their hair, since hair tends to be one color. Some other distinguishing features of human hair include:
- Long length of hair strands
- Smooth and thick texture
- The hair shaft is shaped in the form of a ribbon
- All hair strands are basically shaped the same
Forensic information that can be gained through the examination of human hair includes:
- The race of the person the hair belongs to
- How the hair strand was removed from the head
- If the hair was chemically treated (for example, with color or keratin treatment)
- If the hair was cut or trimmed recently
It is important to note that the sex of an individual can only be determined from hair if the hair shaft is present so that a DNA profile, or genetic information, can be extracted.
Like human hair, animal hair can also provide forensic examiners with useful information. The characteristics of animal hair differ from human hair in several ways, including:
- Animal hair is often used as a defense mechanism or for protection against other animals or humans
- Animal hair is coarse and narrow
- Animal hair tends to be short
- The pigmentation and color of animal hair is not consistent and widely varies
- The root or shaft of animal hair tends to be fanned out
- Animal hairs vary widely in shape without being chemically altered
Through forensic examination, the species of an animal and its habitat can be determined.
Hair evidence found at the scene of a crime can yield important clues for investigators. Both human and animal hair have helped to solve some of our nation's toughest cases. The murder case of James Anagnos was solved through a human hair match, while the homicide of Elizabeth Ballard was solved by the forensic analysis of animal hair.
Although both human and animal hair can tell us stories, they each have unique characteristics. Some distinguishing features of human hair include consistent coloring and pigmentation, long length, and a smooth, thick texture. Examination of human hair can tell us the race of the person it belongs to and if the hair was cut recently, among other things. If a DNA profile can be extracted from human hair, it can also tell us if the hair is from a male or female.
The characteristics of animal hair vary from those of human hair. Animal hair tends to be shorter, coarser, and can vary widely in color and pigmentation. Forensic examination of animal hair can be helpful in determining the animal species from which the hair was derived.