Science

How dastardly squirrels drive crime scene investigators nuts

Not as cute as they look, squirrels needing to chew can wreak havoc on a crime scene
Not as cute as they look, squirrels needing to chew can wreak havoc on a crime scene
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Not as cute as they look, squirrels needing to chew can wreak havoc on a crime scene
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Not as cute as they look, squirrels needing to chew can wreak havoc on a crime scene
"Squirrels seem nice" says researcher Pokines, "but they're actually very voracious little creatures"
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"Squirrels seem nice" says researcher Pokines, "but they're actually very voracious little creatures"

Crime scene investigators already have plenty to worry about. But now they've got one more foe: squirrels. We're not joking. The rodents with razor-sharp incisors chew up crime scenes to maintain their dentition, says new research led by James Pokines at the Boston University School of Medicine.

The new research, published in the Journal of Forensic Identification, provides clear evidence that squirrels (as well as other rodents) can have a dramatic impact on forensic findings, scattering remains and altering bone fragments to the point where signs of trauma to the bone, such as bullet or knife marks, can be obscured or gnawed away altogether. At times rodent damage can even be mistaken for weapon marks themselves.

The simple study involved wiring whitetail deer bones to hundreds of trees and other locations likely to be favored by squirrels, then returning at regular intervals to record any changes at each sample site. They also used a number of motion-sensitive cameras to catch the crafty critters in the act.

It turns out that bone-gnawing squirrels are pretty pervasive. Of the 305 samples placed, 58 had obvious damage caused by the large rodents; just under 20 percent of the total. Researchers also found that by examining the details of the tooth-marks and other damage, they could determine if it was a squirrel or some other rodent species that had been doing the chewing.

"Squirrels seem nice" says researcher Pokines, "but they're actually very voracious little creatures"
"Squirrels seem nice" says researcher Pokines, "but they're actually very voracious little creatures"

To be fair, squirrels aren't teaming up with criminals on purpose. If you've ever had a pet rodent you know the deal; rodent incisors grow throughout the life of the animal. Unless they are continuously worn down, these teeth can become become so long they can't be used. Unfortunately for forensic technicians, bone on bone is a very efficient method for wild rodents to keep their teeth in chipping condition.

Bone gnawing squirrels also sound creepy. "I was entering our backyard when I saw a very large squirrel holding a vertebra in both hands and gnawing furiously on it," recalls Sierra Santana, co-author and student of Pokines. "We startled each other and I just backed out of the yard to let him do his thing."

In addition to helping people understand the prevalence of this kind of evidence disruption, and helping them distinguish between rodent marks and forensically important marks, Pokines and his team are hoping their work will inspire researchers in other countries to document similar damage by other types of rodents. Meanwhile there's a group of well-read criminals looking for spots with an abundance of squirrels, just in case they need a good location to get rid of the evidence.

Source: Boston University

2 comments
Bob Flint
So that explains why they run off and play with my river rocks, to trim down their teeth...
Lbrewer42
" ...says new research led by James Pokines at the Boston University School of Medicine. " I cannot believe the topic of this article! I sure hope this was not paid for with a government grant, but have a feeling it probably was. Have city slickers REALLY come so far away from nature that they are not aware squirrels gnaw on bones? I wonder how much more money these city slickers would need to spend before they realize they also feed on antlers?! Oh no! Maybe they need to waste the money again b/c they may realize that the percentage of chewed upon specimens will also vary depending on how rural the area the test occurs in. They may also want to study whether or not it would be fox squirrels (which predominantly favor cornfield areas as compared to black squirrels). C'mon - maybe these educated eggheads need to take lessons from any farmer (some who may never have graduated from high school). In all seriousness, it this was posted on April first, I would have thought this article it was an Aprils Fool's joke. Let me help the research effort along. You aslo will have chipmunks (much more numerous than squirrels) who feed on the same bones, antlers, and mast squirrels feed on. You had better also look into porcupines (whose teeth marks are normally a bit deeper, but can resemble squirrel and chipmunk gnawing), and... I offer this information for free!