Forensic science is always evolving to better aid in the apprehension of criminals. What if a killer leaves his victim with no fingertips, DNA, or teeth? One way to determine the age of a victim is by examining their eyes.Sounds bizarre, doesn’t it? The soulless eyes of a murder victim allow investigators to determine their age at the time of death. This process is called Radiocarbon Dating.
Radiocarbon Dating
You’re probably familiar with how to tell the age of a tree by examining a split piece and counting the number of rings. Same basic idea when examining a victim’s eyes.
How is this possible?
Each of us, whether we realize it or not, have been exposed to naturally occurring levels of radiation. Most prominent in the 1960’s and 70’s, particles of radiation released into the atmosphere while testing nuclear weapons. Over the years — decades — these particles have fallen to trace proportions. However, there still remains naturally occurring levels of carbon in the air. Different forms of carbon are ingested every day, introducing trace elements into our system. Many carbon compounds are crucial to our way of life. Others are toxic (like cyanide, a carbon-nitrogen bond).
Radioactive particles and naturally occurring carbon settle in the crystallins of the eyes, and Radiocarbon Dating is the process of detecting this manifestation.
What are Crystallins?
Crystallins are microscopic proteins that bind together and collect on the lens of the eye. According to Explore Forensics (one of my favorite sites), crystallins got their name because of how they react under a microscope – like crystals, allowing light to pass through. From the time of conception (conception! Let that sink in…) until age two, these crystallins form in and around the lens of the eyes. At which point the formation stops. When this happens, trace elements of carbon permanently fuse in between the crystallins.
So, when an investigator – usually a scientist or pathologist – conducts a Radiocarbon Dating examination, they’re looking at levels of the carbon fused with the crystallins. To calculate age, they subtract the current levels of radioactive carbon in the eye from the naturally occurring levels of carbon in the atmosphere today. By comparing the levels of radiocarbon in the crystallins to the atmospheric levels they can determine the precise year of a victim’s birth.
Cool, right?
Determining the Sex of a Skeleton
There are many differences between the two sexes, and the variation runs as deep as our bones. This is especially important for corpses in advance stages of decomposition. All that might remain is the skeleton, perhaps teeth, and possibly some hair. Even if the pathologist has teeth and hair to work with, that doesn’t mean enough material remains to ID the victim’s sex
This is where the skeleton offers more information. The only exception would be that of a pre-adolescent, where sexual dimorphism is slight, making the task much more difficult.
The most common way to determine a skeleton’s sex is by bone size. Not the most accurate, but it’s a starting point. For the most part, male bones are larger than female bones because of the additional muscle that increases on the male through adolescence and into adulthood.
Another good inclination of sex is the pelvic area.
The sub-pubic angle (or pubic angle) is the angle formed at pubic arch by the convergence of the inferior rami of the ischium (loop bone at the base) and pubis (top of loop) on either side. Generally, the sub-pubic angle of 50-60 degrees indicates a male, whereas an angle of 70-90 degrees indicates a female. Women have wider hips to allow for childbirth.
There are also distinctive differences between the pubic arches in males and females. A woman’s pubic arch is wider than a male’s as is the pelvic inlet, to allow a baby’s head to pass through.
The pubic arch is also referred to as the ischiopubic arch.
Incidentally, this difference is noticed in all species, not only humans. Same with Radiocarbon Dating.
The area around the pelvic inlet (middle of the pelvic bone) is larger in females than in males. A female skeleton who has given birth naturally will be identifiable because this space widens during childbirth. Even though it contracts afterward, it never fully returns to its original size. In the picture above notice the heart-shaped space.
Other Body Clues
The acetabulum — the socket where the femur (thigh bone) meets the pelvis — is larger in males. Also, the head and skull have several characteristics indicative of one sex or the other.
- In males, the chin is squarer. Females tend to have a slightly more pointed chin.
- The forehead of males slant backward, where females have a slightly more rounded forehead.
- Males tend to have brow ridges. Females do not.
These differences and more tell the pathologist the sex of the deceased.
What Do Forensics and Skeletal Differences Have To Do With Writing?
Everything! Use the differences between male and female skeletons to add realism to fiction. Let’s say, a body is discovered in the blistering heat of the summer. The victim hasn’t been found for months, leaving only the skeleton. By showing the pathologist or Medical Examiner measuring the pelvic inlet, arches, and angles, we’ve essentially ensured our reader isn’t going anywhere.
Same holds true for the lab conducting a Radiocarbon Dating Test on the eyes of a murder victim. Adding forensic details is a lot of fun, too, for the writer and the reader. The trick is to disguise the research in a compelling storyline rather than dumping the information all at once.
Why is the hanging skeleton in doctors’ exam rooms always named Fred? Half the time they’re female. If they make me wait too long, I’m more apt to bring it to their attention. “Fred might need a new name, considering that’s a female skeleton.” And this always surprises them! They’re also less likely to leave me unattended for long in the future. 😉
This little guy is very much alive. Look how convincing he is, though!
Texas indigo snakes—a subspecies of the eastern indigo snake—can grow up to 7 feet long and are found throughout Texas. They’re not venomous, nor constrictors. Instead, they rely on muscular jaws to overpower and swallow their meals head first. Texas indigo snakes even hunt venomous rattlesnakes (they’re immune to the venom).
documented 29 out of 50 different wild ducks played dead when exposed to captive red foxes. This immediate collapse gives the duck a fighting chance should the fox lower its guard. The ducks remained still while the fox carried them back to den to escape later.
Another species of bird that plays dead is the Japanese quail. These animals do so for similar reasons to ducks – to avoid predators, such as cats — and wait for an opportunity to escape. When sleeping, Japanese quail also appear to be dead and can sometimes cause alarm to their owners.
The lemon shark is an apex predator, yet they also play dead. If turned onto its back, the lemon shark will not only play possum, they’ll begin to exhibit labored breathing and the occasional tremor. This is especially interesting, considering the lemon shark lay on the ocean floor and allows other animals to pick the parasites off its body. They have the ability to remain completely still and pump water over their gills to breathe.
This little guy is alive, playing dead.
Native to Japan, the pygmy grasshopper displays a unique version of playing dead when threatened. Not only do they freeze but they spread out stiffened legs as far as possible in all directions. This death stance makes it nearly impossible for predatory frogs to attempt to swallow them. Thus, the frog moves on to easier prey.
This redback spider is alive but playing dead.
And the acting award goes to…
The Central American cichlid plays dead to lure unsuspecting prey. This aquatic predator’s intricate markings give the illusion of a decaying fish. Because scavengers are attracted to an easy meal, they move in. The cichlid springs to life and attacks.
Another animal that plays dead to catch prey is the pselaphinae beetle. Instead of waiting in ambush, these beetles employ tonic immobility so ants can carry them away. Once they get inside an ant’s nest, they spring to life and feed on the ant larvae (the majority of their diet).
Black widows are the most venomous spiders in North America, but they don’t always bite when threatened or provoked. Instead, black widows often play dead. When their lives are at risk, they curl into a ball while releasing silk to aid its movement.
Blue Jays play dead by slumping down, motionless. Sometimes, like their crow cousins, they’ll sprawl out with their wings spread, head flopped to the side. Some birdwatchers theorize this is a form of blue jay sunbathing. Or they’re playing a practical joke since they often surprise people by springing to life if disturbed. When threatened by predators such as cats and hawks, they will absolutely play dead.
Praying mantis are easily recognized by their long narrow bodies, a small head with large eyes, and oversized front legs held upright. To avoid being eaten by the female after mating, the male will play dead. They will only move again once the female has lost interest and left.
Not to worry. She’s alive, just not in the mood.
Thank you for standing in for the human, sweet puppy.
Becca Puglisi
Many believe those who procrastinate are lazy or unmotivated. It can be true of some, I suppose. Most, however, are caught in a torturous loop that stems from the brain. Once you fall prey to these endless cycles, it’s difficult to claw your way out.