Reddit thinks dogs can stay away from bottles with red liquid. A vet fact-checks the viral claim

Last week, on a Bangalore-centric subreddit (r/Bangalore), Redditor flynplanes uploaded a peculiar photograph of Bisleri bottles filled with a maroonish liquid, placed outside several residential gates. One might think of this as a move of generosity for weary travellers to just sip on some Roohafza (please don’t drink anything from any unidentified bottles though). 

But the intended demographic for these bottles doesn’t include humans. Rather, the red liquid is being seen as an alternative to drive away stray dogs. Apparently, the canines can be scared off not just by red liquid, but also liquids of other colours.

What is this liquid? Underneath flyplanes’s post asking the meaning behind these bottles, another Reddit user yuzaaname commented, “People say dogs don’t come around. Less dogs = Less dog poop in front of the house. Most people who use fabric whitener (Ujala) don’t know what this is.”

From the looks of it, it is tough to ascertain what the nature of the red liquid but given the tendency for many Indian households to store disinfectants or toilet-cleaning liquids in used water bottles, it is highly probable that the bottle’s contents might include this (definitely not Roohafza). 

Kerala-based Redditor krsj1234 also adds the Ujala theory saying that the blue liquid is stored in bottles by some Keralite households to drive away dogs. Other Redditors affirm that they too have observed this practice in regions like Odisha, Vadodara (Gujarat), and Kolkata (West Bengal). 

In the case of Gujarat's Rajkot, one of the comments also quotes Dr BR Jaksania, a local veterinary officer, as saying, "We have seen that some societies have started using red water to scare the dogs. Animals are allergic to red colour and get furious. So they avoid going there." It is easy to think about dogs being "allergic" to red but the science behind dogs' vision is more complicated. 

How colour-blind are dogs? One of the common recurring tropes in dog jokes is their colour blindness. However, contrary to popular notions, this doesn’t imply that dogs see the world in black-and-white. 

Veterinary doctor and “Vet YouTuber” Dr Hansika Singh breaks down the optic conditions of dogs, “A dog's ability to sense different colours is limited. They have only two colour receptors (called cones) in their eyes, whereas most humans have three.”

She adds that the two cones present in dogs perceive wavelengths of light that correspond to blue and yellow. So, the colour blindness in dogs is actually limited colour perception or what is technically known as dichromatic vision. 

Singh adds,

This can be contrasted with non-colour blind humans who can detect combinations of red, blue, and green (RBG), allowing them to perceive everything in all its colour. 

But dichromatic vision in dogs still doesn’t offer any explanations behind the belief that these liquids would spook them out. 

Would the liquids scare away dogs? Even though Indians are claiming that the strategy actually works, the veterinarian says, “There is no scientific evidence to support this theory and so should not be counted on.”

Another theory floating on the internet is that the liquid is perceived as kerosene or acid by dogs, contributing to their fears. Redditor Important_Park_7196 discredits the fact that all dogs would be scared by giving the example of their own pets. 

“Stupid theory that it dissuades dogs from peeing there. No substance to it. My dogs happily sniff and pee on these bottles.”

So, while there might be a 50-50 factor behind this strange strategy, it is also worth noting the differences in reactions between strays and pet dogs when they encounter such substances. More scientific research is definitely needed to arrive at concrete conclusions. 

While it is easy to think that the red colour often signifies danger and dogs might be alerted but as discussed above, their dichromatic vision would allow them only to perceive the flashy red colour as a pale yellowish-brown shade. And with the rest of India resorting to indigo blue liquids, dogs can detect bluer shades more distinctly but that still doesn’t answer whether it would intimidate them. 

Not the most advisable method against stray dogs: Lastly, Singh asserts that using toxic substances like liquid detergents shouldn’t be provided as she personally feels that activities which can expose dogs to danger should strictly be discouraged. 

Instead, she offers the familiar solution that many within the veterinarian circle recommend, “The man-animal conflict can be dealt with in a scientific way by getting them sterilised under Animal Birth Control (ABC) Programme and they also get vaccinated against rabies in this process.”

Now, the question is would you want to take the initiative to get your neighbourhood's strays sterilised, or just avoid the dogs altogether, or offer them poisonous Roohafza (don't)!

(Meanwhile, here's a story on training your pet dogs better.)