There is one common thing between humans and the dogs, we greet each other when we meet someone. Though the ways we do that are different, they may not be as different as we once thought.
And the surprising truth about why humans shake hands, is the same reason why dogs sniff each other's butts (sort of, though not precisely).
According to the Guardian, a study conducted at the Israel's Weizmann Institute of Science found that after people shake hands, they sub-consciously "sniff" their hands after it. This is mainly done to identify the clues about a person's identity.
To be precise, Professor Noam Sobel led a research team that secretly filmed 280 people before and after they said "hello" to a researcher, which sometimes meant shaking hands.
About 20 per cent of the time, the participants were sniffing their hands before and after greeting each other with a handshake. If the participants and the researcher were of the same sex, the participants would spend double the amount of time sniffing their right hand.
But a handshake with an opposite sex resulted in an interesting result; the participants were more likely to sniff their left hand than their right hand which was used in the handshake. There is still no concrete answer as to why this happens, but the research team suggested that the individuals sniffed their hands to assure themselves that the person they're greeting, does not gives off a bad smell.
Sobel says that "Unlike rodents, cats and dogs, it isn't socially acceptable to walk up and sniff each other. We think this is a way we've developed to collect this information in a subliminal fashion. Handshaking is already known to convey a range of information depending on the duration of the gesture, its strength and the posture used. We argue that it may have evolved to serve as one of a number of ways to sample social chemicals from each other, and that it still serves this purpose in a meaningful albeit subliminal way."
To determine what chemicals are being exchanged during a handshake, the researchers put on sterile gloves during a handshake.
The chemicals that they found were squalene and hexadecanoic acid, which are the same chemicals that the dogs and cats use for attraction purposes.
