Question Of The Day: Why Would My Dog Bark At UPS, But Not FedEx?

Question: Why does my dog freak out at UPS trucks but not at FedEx?

Delivery services like UPS, FedEx, and the USPS provide specialty training in how to deal with aggressive animals. But that doesn’t address a curious question that plagues UPS drivers and dog owners alike: why does my normally docile poodle lose his mind over the UPS delivery person, but just keep on keeping on when FedEx or the mailman passes by?

Recent research from has proven that dogs are not colorblind, despite that common belief. As Joseph Stromberg explained for Smithsonian.com, “A dog sees grayish brown, dark yellow, light yellow, grayish yellow, light blue, and dark blue, respectively.” So, theoretically, a dog could distinguish the trademark UPS brown from other colors of delivery vehicles rolling down the street.

Another trigger for barking aimed at the UPS guy or gal might be based on a learned behavior from a prior experience.  In the ASCPA’s pet  behavioral guide to barking, several factors accounted for “Why Dogs Bark,” including territorial barking and greeting barking. For example, if the dog spots the delivery person hurrying up the walk to the front door this could lead to territorial barking. The dog is alerting you and warning the newcomer that he or she is “approaching their territory.”

Spend some time on UPS employee sites like BrownCafe and you’ll see comments and threads relating to how to deal with dogs on your route. Many drivers carry dog treats with them to grease the wheels with their canine customers. So if Fido is barking, it might be because he knows that treats are on the way.

Maybe the most interesting possibility has to do with some of the design and science around the unique UPS vehicles. According to UPS, their delivery fleet includes 99,892 package cars, vans, tractors, and motorcycles, including 5,461 alternative-fuel vehicles. UPS has added some lightweight composite-body vehicles designed to lower fuel consumption by 40 percent. It’s those package cars, the large modified, and square, boxy looking vehicles that often send dogs over the edge.

While not all package cars (don’t call them trucks!) are the same, there are some similarities that produce a unique sound profiles. Each package car (even the new composites) has a metal floor and interior structure to hold the weight of the shipments. This, along with the lightweight sides and plastic roof, creates a distinctive rattle and shake. There is also the high-pitch frequency caused by the diesel turbochargers that many package cars have under the hood. Turbo engines are notorious for producing ‘turbo whine.’ Ultrasound (any sound with a frequency above the audible for range of hearing) for humans is more than 20,000 Hz. Dogs can detect frequencies as high as 45,000 Hz. So it is possible that Big Brown’s turbochargers are acting like giant dog whistles heading around the corner putting all the doggies on alert.

There probably isn’t a one-size-fits-all answer, says Dr. Suzy Fincham-Gray, a veterinarian and writer from San Diego. “From sniffing out dog biscuits hidden in a pocket to detecting the specific pitch and frequency of an engine, dogs have much keener senses than ours, which means there might even be an extra factor we aren’t aware of that causes our canine companions to bark at that UPS truck.”

We’re scouring the Internet to uncover interesting questions that people have posted looking for advice from the unwashed masses. We will contact experts to give you well-researched, professional advice. You can also submit questions to autos_qotd@yahoo.com.