COUNCIL CHRONICLE – A chemical scent released by spilled blood leads to very different reactions in humans and animals, marking a quite clear limit between hunter and prey. The research team behind this new study also claims that this is the first detection of a chemosignal that affects both “human and non-human animals alike”.
The Chemical Scent that Drives Animals Crazy
The study targeted a molecular component of animal blood known as E2D. This appears as the fats in the blood start breaking down as they are exposed to air, meaning that the chemical scent appears together with open wounds.
E2D was first identified back in 2014, as it was isolated from pig blood. Its olfactory appeal was then tested with some ‘help’ from Siberian tigers as well as three wild dog species. All of them went into a frenzy as they were reportedly sniffing, licking, pawing, toying, and biting at the wooden legs covered with E2D. The animals’ behavior closely resembled their reaction to actual blood.
For this latest research, the team tested the effects of this chemical scent on less blood-thirsty species. They did so to test the hypothesis that E2D’s metallic odor wouldn’t go unnoticed.
“We hypothesized that prey species would be under evolutionary pressure to become sensitive to E2D to help them avoid an area where a bloodbath is going on,” says Johan Lundström, a biologist part of the Karolinska Institute, Sweden.
This revealed that just as E2D attracted the staple predator species, it did the exact opposite to animals that fall prey to others. Upon sensing this chemical scent, these latter had a flight, not a fight response, just as they reacted to blood.
The study also tested the reaction of 40 human volunteers that were exposed to E2D. These were noted to recoil, a reaction which the scientists interpreted as a sign of aversion to the odor.
This was also the reaction to a small quantity of E2D.
“Our finding in humans fits in with the paleontological data showing that early primates were small-bodied insectivores,” explained Lundström.
The research states that although humans are “predators”, they also probably evolved from a “prey species”, and that certain traits of those times still survive even in modern-day people.
Detailed study findings are available in the journal Scientific Reports.
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