Earlier this week, Florida police posted that they had used a jar of sweat to help a K9 officer locate a missing elderly woman with dementia. Using dogs to help track missing people is not a new police tactic, and they've repeatedly had success by using an item of clothing or household item with the missing person's scent. Is a jar of sweat that much better?
"Simply enclosing an item will help the odor remain for much longer," explained Alexandra Horowitz, a dog cognition expert at Barnard who studies canine olfaction. "Smell dissipates over time, so anything left out in the open will lose a lot of its odor into the surrounding air. Hence the explanation for why you can open a sealed drawer or room and suddenly be hit with a strong odor: it's been trapped inside."
Human scent preservation kits are designed to keep a person's unique scent in a sealed container. You dab some sterile cotton under your armpit (or under the armpit of your family member), stuff it in a jar, seal it, and label it. Then, if the person goes missing, police can expose the scent to one of their canine units for a quicker search.
The Citrus County Sheriff's Office, on Florida's Gulf Coast, posted on Facebook this week that just such a kit helped their K9 officer Ally locate the woman—who had been missing for two hours—in just five minutes. Ally got an ice cream cone as a reward.
These kits have long been championed by police and non-profit groups that advocate for dementia care. Horowitz told me that concentration matters most when it comes to detection, which is why a kit like this can be particularly useful. But she said trained dogs are pretty adept at tracking scents.
"In general I don't think it is a challenging task for trained dogs," she said. "Note that they are not trained to learn to smell better: they are just trained to care to tell us when they notice what they naturally do, which is the scent of someone missing."
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