Tag Archives: Forensic Anthropology

Skull and Bones at Karluk Lake

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In my upcoming novel, Karluk Bones, my protagonist, Jane Marcus, and her friends stumble across a human skull and bones in the woods. Are the bones ancient or recent, and how did they end up in the middle of the wilderness? Jane contacts Alaska State Trooper Sergeant Dan Patterson, and he sends the bones to an anthropologist at the University of Alaska in Anchorage. The bones end up in the laboratory of a young graduate student named Ying Lee, and Patterson gives Jane permission to fly to Anchorage and learn what Ying has to say about the bones.

The following is an excerpt from Karluk Bones

“Come in,” a female voice called. A young woman met me inside the door and introduced herself as Ying Lee. Ying had short, black hair, big blue eyes, and creamy white skin. She motioned for me to follow her, and her petite frame bounced with energy as she led me down the hall and into a small laboratory. My bones, now scrubbed clean, held center stage on the work table in the middle of the room.

Ying wasted no time with small talk. She walked to the table and held up a portion of the long leg bone we had found. The rest of the bone rested on the table. For some reason, Ying, or one of her associates had sliced the bone into two pieces. Her blue eyes blazed with intelligence and excitement. Her enthusiasm infected me, and I walked to the other side of the table and focused on her.

Ying held the bone with both hands. “We’re very fortunate to have a femur,” she said, “because the femur offers an easy estimation of height. All I needed to do was measure the bone and then apply a simple formula to obtain an estimate of the individual’s height.”

“And he was tall?” I asked

“Well, yes, he was a little above average height – about six feet tall.” Ying said.

“So, we know he was male from his height?” I asked

“I would guess the individual was male from his height, but you also found the pelvis, and I can confirm he was a male from the pelvis.”

“Next, I set out to determine the age of the individual when he died. Luckily, I had the skull to examine.” She pointed to the skull on the table, and I noticed she had glued several of the miscellaneous bone fragments we’d gathered to the skull. It still wasn’t complete, but she had pieced much of it together.

“You see here,” Ying said. Pointing at an area she had reconstructed on the top of the skull, “these lines are called cranial sutures. The bones that enclose the brain grow together during childhood. As a person ages, these sutures gradually fade. This fading, or remodeling, varies among individuals, but some sutures close at a consistent age in most individuals.” Ying pointed to the back of the skull and ran her finger along a faint line. “This is called the lamboid suture. It generally begins to close at age 21. The closing accelerates at age 26, and the suture is completely closed between age 30 and 40. You can see the suture on this skull is nearly, but not completely closed.”

“So, how old do you estimate he was?” I asked.

“I’d say between 25 and 30 years old,” Ying looked up from the bones and met my gaze. “This is only my estimate, though. I couldn’t swear to it in a court of law, but I think this individual was between 25 and 30 years old when he died.”

“I understand,” I said. “Your estimate gives me somewhere to start. I appreciate it.”

A quick smile passed over Ling’s thin lips, but then she was all business again. “Again, by looking at his skull, I determined this individual descended from European ancestry. There’s not much left of the nasal bones, but the narrow face leads me to believe with little doubt this skull did not come from a Native Alaskan individual.”

“Okay,” I said. I wanted to make sure I’d understood everything Ying had told me. “We have a fairly tall Caucasian man in his late twenties.”

Ying wrinkled her nose. “I don’t like the term Caucasian, because race tags can be misleading. All I can really tell you is his ancestors were most likely from Europe.”

I nodded and forced myself to remain silent. I wanted to blurt out my questions. How long ago did he die, and what killed him? But I knew how much I hated to be interrupted while explaining my research to someone, so I let Ying explain these bones to me in her own style and at her own pace.

She stared at me for several moments as if expecting me to question her, but then she continued. “The question is how and when did this individual die?”

I nodded and watched her expectantly.

Ying pointed to the front of the skull. “I think I know how, but the when part is a big guess.

“What do you mean?” I asked.

“My professor and I are fairly certain this man died from a gunshot wound to the top of the head. I pieced as much of the skull together as I could, and you can see this jagged, roughly round hole in the top of the skull.”

“You’re sure it’s a bullet hole?”

She smiled. “I’m not certain of anything, but I’ve compared this hole to dozens of known bullet holes in skulls, and it is similar.”

“Is there any way to determine what gauge bullet caused the hole?” I asked.

Ying laughed. “If the particular type of bullet becomes important, you might be able to run down an expert who’d be willing to give it a shot.” She stopped and laughed at her unintended pun. “This is not my area of expertise, but I do think it is a bullet hole.”

“It seems like a weird place to shoot yourself,” I said.

Ying looked at me sharply. “Do you have reason to believe this person committed suicide?”

“No, I’m just thinking out loud,” I said

“It’s just that . . .” Ying shook her head.

“Just what?” I asked.

“My Ph.D. thesis is linked to studying nutrition in ancient populations. In particular, I’m studying nutrition in communities of Inupiat people. Most of the bones I’m looking at are between 150 and 300 years old. You are a biologist, so as I’m sure you know, teeth and bones contain a protein called collagen. Collagen absorbs chemicals such as calcium, carbon, nitrogen, and strontium from the food an individual eats. Different types of food contain these elements in different ratios, and from studying fossilized bones and teeth, I am attempting to understand the diets of various populations of Inupiat people. Were they healthy? Did they face periods of malnutrition? That sort of thing.”

I nodded. “Your work sounds interesting.” Her research did sound interesting, but I had no idea why she was telling me about it in relation to these bones.

She seemed to read my mind. “When I received permission to study these bones,” she gestured to the bones on the table in front of her, “I thought it would be interesting to see how much the diet of this guy differed from my Inupiat bones.” She shrugged. “I know it has nothing to do with your case, or at least I didn’t think it did until I started analyzing the bones.”

“What do you mean?” I asked. I still couldn’t guess where she was going with this.

“This guy,” she put her hand on the femur, “was starving to death. If he didn’t have a bullet hole in his head, I’d say he did starve to death. I wondered if he shot himself to end his suffering, but you’re right, it’s a strange angle for a self-inflicted gunshot wound.” She shook her head. “It would be possible, though, especially if he used a rifle.” She held an imaginary rifle in front of her, pointed at her head.

“Wait a minute,” I said, “back up. You think this guy was starving to death?”

“That’s one of the few things I can say with any certainty about this individual,” Ying said. “His bone mineral density is extremely low. He was emaciated when he died. In fact, his bones are the most emaciated bones I’ve studied.”

“Interesting,” I said. “I wonder what happened to him?”

Ying studied me, her eyes ablaze. “Isn’t it fascinating? I love learning about past civilizations and imaging what the people’s lives were like. I feel like a detective sifting through the debris and trying to find the important evidence.”

I smiled at this brilliant young woman and was thankful my bones ended up in her laboratory. “When did he die?” I asked. “How long have his bones been at Karluk Lake?”

Ying shoulders dropped, and the fire in her eyes died. “That’s the million-dollar question. It’s very difficult to estimate the time since death from skeletal remains. I know he’s not ancient, but there’s little difference between five-year-old and ten-year-old bones.”

“But you told Sergeant Patterson you thought these bones were between thirty and fifty years old.”

“Yes, well, I didn’t make that estimate,” Ying said. “When these bones first arrived, we had a professor here who was visiting from UC Davis, and her field of interest is studying bone chemistry to estimate the time since death. She looks at the citrate content in the bones. She took two slices of the femur back to California with her, and she arrived at the timeframe of thirty to fifty years, but she stressed to us, and I told Sergeant Patterson the timeframe was only her best guess.”

I smiled at Ying and held out my hand. She took it, and we shook. “I appreciate all you’ve done. I don’t know what it means yet, but I hope to figure it out and maybe even learn who this individual was.”

“If you come up with a possible identification and can find relatives, we can attempt to extract DNA from the bones and see if there’s a match.” Ying said. “We might even be able to tap into a public DNA database.”

“Thanks, I’ll keep that in mind. I hope I can figure out who you have on your table.”

I will let you know when Karluk Bones is available. Meanwhile, be sure to sign up below for my free Mystery Newsletter.

Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.

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You Are What You Eat: Bones Offer an Encyclopedia of Diet, Disease, and Trauma

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What types of food did this individual eat, and did she die from a disease or trauma? Skeletal remains offer anthropologists a view into not only how a person died but also how they lived. As science and technology advance, we have more tools at our disposal to examine human remains and learn about individuals, societies, and cultures. Over the last few weeks, I’ve discussed what an anthropologist can learn from skeletal remains, including whether the skeleton is male or female, the race and height of the individual, and the age of the victim when he or she died. This week we will consider how this person lived and died.

Recent excavations at the Jamestown colony in Virginia gave anthropologists a glimpse into the harsh winter of 1609-1610 when the colony ran out of food, and only sixty out of five-hundred colonists survived. Gravediggers couldn’t keep up with the ever-growing pile of bodies and ended up placing two or three at a time in a single grave. Skeletal remains provided evidence of starvation, and tool marks found on some skeletons suggested other colonists had carved and eaten their flesh. While stories passed down through the ages from Jamestown have mentioned incidents of cannibalism, the skeletal remains produced the first confirmation.

Diet

Isotope Analysis has given us some of the most interesting information about what our ancestors ate and how they moved in relation to their resources. Most people know about radiocarbon dating or C-14 analysis. C-14 is an unstable isotope of carbon, and it deteriorates at a known, predictable rate. By measuring the amount of C-14 in old bones, scientists can estimate the age of the bones.

In contrast to C-14, Carbon-13, Nitrogen-15, Oxygen-18, Strontium-86, and Strontium-87 are all stable isotopes, and they do not decay over time but remain constant. The ratios of these isotopes vary in different foods and in the environment, and depending upon what we eat and where we live, our bones incorporate these compounds in different amounts and form a record of our lives. Scientists call this our isotopic signature. Isotopic signatures offer archaeologists a way to learn about the environment at a particular time and place and to understand the factors that influenced the way a community developed. A direct relationship exists between the diet of an individual and the isotopic signature in his bone collagen. Did he eat grasses, fruits, meat, or fish and shellfish?

The study of isotopes also provides researchers with information about mobility and migration of past cultures and individuals. Humans move for many reasons, including the search for more plentiful food, to find a suitable mate, for warfare, and for trade. Strontium and Oxygen isotopes are used to reconstruct past movements of an individual. If a person lived his life in the general area where he died, then the isotopes in his bone collagen will match the isotopes in the environment where he was found. Local isotopes are measured from the substrate, groundwater, and precipitation of a place. If his bone and teeth enamel isotopes differ from the local environmental isotopes, then the archaeologist knows the individual traveled to this region from somewhere else.

Disease

Bones display evidence of many diseases and trauma. Healed fractures, even ones which are several years old, often leave marks on bones. In osteoarthritis, the bones rub together, creating eroded and polished bones. Rheumatoid arthritis causes swollen joints which can push against and deform bones. Ankylosing spondylitis produces an inflamed spine which leaves characteristic markers on the vertebrae. Gout causes increased uric acid in the blood which can crystallize in the joints and cause an erosion of the joint surfaces. Cancers can affect a skeleton in two ways. Cancers in the soft tissue next to a bone create pressure on the bone, often causing lesions or holes in the bone. Cancers producing tumors directly in the bones cause skeletal changes which can be seen long after the soft tissue has decomposed.

Infectious diseases can also leave a trace on bones. Tuberculosis causes lesions in the bones, especially the ribs, spine, and pelvic bones. Syphilis, a sexually transmitted bacterial disease, forms degenerative pits on the surface of the bone and is especially severe on the forehead, nose, and shin.

As DNA research progresses and Methods of DNA sequencing become more affordable, we will learn much more about the diseases an individual suffered from studying his bones. Chromosomal abnormalities have been identified in DNA extracted in human bones 7400 years old, but scientists believe non-human DNA will be the most useful in identifying the importance of diseases such as malaria, cholera, and the plague in ancient communities.

Malnutrition and Starvation

Malnutrition and starvation lead to decreased bone mineral density. Long term malnutrition causes stunted growth and an increased risk of bone fractures. Oddly, bone marrow adipose tissue (BMAT), a type of fat, increases during starvation while other types of adipose tissue decrease. Scientists are uncertain why BMAT increases when a person is starving to death, but they believe BMAT is either a passive filler occupying spaces left by dying bone cells, a consequence of suppressed bone formation, or an adaptation for surviving starvation.

Next week, I will post an excerpt from my upcoming novel, Karluk Bones, and you can read how a young anthropology student explains her analysis of human bones found near Karluk Lake on Kodiak Island. 

Be sure to sign up for my free mystery newsletter, and I’ll see you back here next week.

Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.

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Age of Skeletal Remains

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Age is critical information when attempting to identify skeletal remains. How old was the individual when he died, and how long has he been dead?

Two weeks ago, I discussed how a forensic anthropologist determines gender from skeletal remains, and last week, I described how an anthropologist can deduce race and height from an examination of human bones.  This week’s post covers ways a forensic anthropologist pins down age. When we talk about age in relation to bones, we must consider two separate issues. First, how old was this individual when he died, and second, how long ago did he die? If you are an investigator trying to determine the identity of skeletal remains, then the answers to both questions will aid you in your investigation.

How old was this person when he died?

When examining a skeleton, a forensic anthropologist considers the processes of growth and decline. Bone growth and tooth emergence can be used to age the skeletons of children, adolescents, and young adults. Once an individual reaches adulthood, his bones stop growing, and his bones, joints, and teeth begin to decline from wear and tear. The rate and degree of decline is far more variable than the process of growth, so anthropologists often struggle to age the skeletal remains of adults.

When we are born, our “bones” are mostly soft cartilage. As we grow, the cartilage is replaced by bone at areas called a growth plate at the end of each bone. Once growth is complete, the growth plates fuse. Infants have more than 300 growth plates which eventually fuse, and since the growth plates fuse and different, known rates, an anthropologist estimates age by analyzing the fused and unfused plates. Teeth also emerge from the gums at a predictable age and provide an accurate estimate of age in juveniles.

Forensic anthropologists can estimate the age of young adults by looking at the skull. When we are born, our skull consists of five flat bones connected by fibrous material called sutures. These sutures allow our heads to expand as we grow, but once we reach adulthood and stop growing, the sutures begin to fuse, and most are completely fused by the time we are 40-years old. If the sutures on the skull have not yet fully fused, then an anthropologist can use them as a rough guide to estimate the age of the individual.

Once bone growth stops and the skull sutures have disappeared, the forensic anthropologist must estimate age at the time of death by studying the degenerative changes in the skeleton. Joints are prone to deterioration, and the pelvis is one of the most common areas used for age estimation. The two halves of the pelvis meet above the pubic area at a joint called the pubic symphysis. This joint undergoes consistent changes throughout a person’s life and can be used to estimate age. Another consistent change in the human body is the cartilage between the end of the fourth rib and the sternum. Over time, this cartilage slowly changes to bone. Other degenerative changes in the spine and joints provide clues to the age of the individual.

I suggest this excellent slideshow for more information on ways to age skeletal remains.

How long ago did this person die?

One of the most difficult questions a forensic anthropologist is asked to answer is how long skeletal remains have been at the location where they were found. If investigators hope to compare the remains to a list of missing persons, they need an estimate of the time since death.  Forensic taphonomy is the study of the factors, including environmental factors, which affect decomposition. Biotaphonomy is the study of how the environment affects the decomposition of the body, and geotaphonomy is the study of how decomposition of the body affects the environment around it. Forensic entomology is the study of insect progression on a corpse, and advances in this field now provide researchers with an accurate estimation of the time since the death of a recent corpse.

The post-mortem interval of skeletal remains more than a few years old is difficult to pinpoint. The environment takes a toll on bones. In a hot, dry environment, bones crack over time, while bones submitted to a cycle of thawing and freezing disintegrate into fragments. Recent research has focused on measuring the citrate content of bone for an estimation of the time since death, but results have been varied, and more research is needed. For now, forensic anthropologists often used their best guess from years of examining bones to determine the post-death interval of skeletal remains.

Next week, I’ll touch on other information experts can learn by examining skeletal remains, including what long-deceased populations ate to survive.

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Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.

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What Can a Skeleton Tell You?

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Last week, I asked you if you discovered a skeleton or a pile of bones in the woods, would you be able to read the skeleton and understand its secrets? In my last post, I discussed how a forensic anthropologist determines gender from skeletal remains. This week, I’ll explain how a forensic anthropologist deduces the height and race of an individual by looking at his skeleton.

Race:

Anthropologists shrink away from the term “race” and instead refer to an individual’s ancestry. Humans are often a mixture of ancestries, so race can be difficult to determine from skeletal remains.

Skulls in people from European ancestry are generally long and narrow. The eye sockets appear rounded with squared margins. The narrow nasal aperture sits high on the face, and the nasal bridge is prominent and sharply angled. The teeth appear small and are spaced closely together.

Asian skulls have circular eye sockets and heart-shaped nasal apertures. The nasal bridge is less pronounced than it is in European skulls, and it is gently angled. Asian skulls have shovel-shaped upper incisors.

African skulls have rectangular eye orbits. The nasal aperture is wide, and the nasal bridge is flat. The jaw protrudes from the rest of the face, and the teeth are large and spaced wider apart than those in individuals with European or Asian ancestry.

Height or Stature:

A close correlation exists between the length of a limb and the height of an individual, and anthropologists have conducted numerous studies to measure the mathematical relationship between limb length and the known height of individuals. From these studies, researchers have developed mathematical formulas for various bones which can be used to estimate height. These equations vary depending on the ancestry and gender of the individual.  For example, if you find a femur measuring 41 cm (16.14 inches) in length, then depending on the gender and ancestry of the individual, you will use one of the following equations:

  Male Female
European 2.32 x Femur + 65.53 ± 3.94 cm 2.47 x Femur + 54.10 ± 3.72 cm
Asian 2.15 x Femur + 72.57 ± 3.80 cm Use Male Formula
African 2.10 x Femur + 72.22 ± 3.91 cm 2.28 x Femur + 59.76 ± 3.41 cm

In the above example, if we have determined our skeleton is a male of African ancestry, then to calculate the individual’s height from his femur, we would use the following calculation:

2.10 x 41 + 72.22 = 158.32 cm ± 3.91 cm (or 62.33 inches ± 1.54 inches)

Similar equations exist for correlating height to the length of the tibia, fibula, humerus, ulna, and radius. If you have several bones available for a given individual, you can increase the accuracy of height estimation by applying the formulas to two or more bones.

Next week, I’ll explain some of the techniques forensic anthropologists use when examining skeletal remains to determine the age of the individual at the time of death. I’ll also explore whether it is possible to estimate the time since death from looking at skeletal remains.

Be sure to sign up for my free mystery newsletter, and I’ll see you back here next week.

Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.

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Bones

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If you stumble across a pile of bones in the woods, can you tell if they are human bones, and if they are human, did they belong to a male or female? How old was he or she at the time of death? Was the individual tall or short? What killed him or her, and how long ago did the person die?

While we might be able to identify human bones, most of us cannot answer many questions about the bones, and most of the answers elude even law enforcement officers, coroners, and trained medical examiners. Forensic anthropologists are the experts who interpret skeletal remains.

In my latest novel, Karluk Bones, Jane Marcus and her friends stumble across skeletal remains near Karluk Lake on Kodiak Island. They find a skull as well as a long femur, so they know at least some of the bones are human. The remains don’t appear to be recent, but they also don’t look ancient, and Jane and her friends argue about how old they might be. Jane reports the bones to the Alaska State Troopers, but Sergeant Patterson also can’t guess at the age of the bones, so he hands them off to a medical examiner who in turn sends them to a forensic anthropologist, and she is able to answer some, but not all, of the questions about the bones.

I love learning, and one of the things I enjoy most about writing fiction or non-fiction is having the opportunity to dig into a new subject and study it not only until I understand it but until I know it well enough to explain it to my readers. Using science to help solve the mystery of the bones in my novel proved trickier than I expected, and Ying, my fictional anthropology student at the University of Alaska, ended up relying on cutting-edge scientific techniques to provide answers about the human remains Jane and her friends found.

Beginning with this post and continuing for the next two or three weeks, I will describe what a forensic anthropologist can deduce from bones.

Human or Non-Human

It is easy for us to recognize a human skull, and most laymen can identify many other human bones, but if you discover skeletal remains in the woods, human bones might be mixed with those of other animals. If a forensic anthropologist visits the scene, she can quickly separate human from non-human remains. If a forensic anthropologist is unavailable, then investigators must collect all the bone scraps and send them to an anthropologist to be sorted in the lab. Once they are in the lab, the anthropologist cleans the bones and attempts to provide a general physical description of the individual whose remains she is studying. The description includes:

  • Gender
  • Age at Death
  • Race
  • Height

The anthropologist also tries to try to determine the cause of death as well as estimate how long ago the individual died. This week, I will discuss how gender can be determined from bones.

Gender

The pelvis and the skull provide the most useful information for determining the gender of the individual.

Pelvis

Females have wider pelvises to provide enough space for the birth canal, and anthropologists use several definitive measurements to differentiate the pelvis of a female from the pelvis of a male. In most cases, though, a forensic anthropologist only needs to visually examine a pelvis to determine the gender of the individual. If the pelvis is available, it is the best bony structure to confirm the sex of the person.

Male (left) Female (right)

Skull

Often, only the skull of an individual is found, but luckily, marked differences exist between the skull of a male and the skull of a female. An adult female’s skull remains slender and retains the smoothness of youth, while and adult male’s skull is more robust with heavier bones and larger muscle attachment areas. Females have a rounded forehead, while a male’s forehead slopes back at a gentle angle. A male has a more prominent brow ridge and square eye sockets, while a female has round eye sockets. Males have a square jawline, and a female’s jaw is pointed.

Since individuals vary, sex determination using only the skull is not as definitive as a confirmation made from examining the pelvis, but the skull usually provides the anthropologist with an educated guess at the gender of the individual.

Next week, I’ll discuss other characteristics a forensic anthropologist learns from reading bones. Meanwhile, be sure to sign up for my monthly Mystery Newsletter about true murder and mystery in Alaska.

Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.

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Sign Up for my free, monthly Mystery Newsletter about true crime in Alaska.