Drug sniffing dogs are becoming more and more irrelevant as marijuana earns legal status across the U.S.

K9 units, also known as police or sniffing dogs, are used to track scents and spot suspicious smells. In the age of legal marijuana, their services are becoming more and more irrelevant, with different states having to retire them due to the legal complications they provide. Retiring police dogs isn’t as ominous as it sounds; these guys are simply given up for adoption or sent to a different state to do their work.

Police dogs are trained to sniff out narcotics, cannabis among them. Dog alerts give police officers probable cause to conduct a search. With legal marijuana programs in place, this becomes an issue, because dogs can’t discern between a large amount of cannabis or a single joint — or even between cannabis and other forms of illegal narcotics.

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All dogs that have been trained by police officers to sniff out marijuana will likely be retired once their state legalizes cannabis. It’s unlikely that these dogs will be able to be retrained; dogs won’t likely be able to forget a smell or stop a response they’ve been trained to learn all of their lives. In order to continue using K9 units, new dogs must be brought aboard and trained to alert police officers to the presence of drugs like cocaine, MDMA, heroin, and any other illegal substance.

While it’s sad to rob dogs out of their life’s purpose, according to a report published by Reason, dogs are pretty bad at sniffing out drugs. One example they provide is Lex, a drug-sniffing dog based in Illinois. The dog alerted for narcotics 93% of the time but was wrong in over 40% of cases. This is a troubling statistic, one that indicates that dogs simply provide ample opportunities for cops to search people and cars.

Police dogs are also biased towards their handlers, picking up on their cues even if there are no drugs around. This gives handlers too much power and the ability to search people without having probable cause.

RELATED: How Accurate Are Drug Sniffing Dogs?

With legal marijuana programs in place, states like New Mexico have been forced to retire their sniffing dogs. These can be adopted by their handlers or donated to a different state that has no legal marijuana program yet. Other states, like Colorado, have ruled that police need to establish probable cause before launching K9 units. Hopefully, sometime soon, more and more police dogs can retire. We wish them a lot of naps and treats.