Articulo en Español e Ingles (Spanish & English article)
People find the smell of blood unpleasant, but for predatory animals it means food. When behavioural researchers at Linköping University in Sweden wanted to find out which substances of blood trigger behavioural reactions, they got some unexpected results.
African wild dogs compete for a log impregnated with blood or a single component. Both were equally attractive. Credit: Linköping University
Matthias Laska is professor of zoology, specialising in the sense of smell. For some time his focus has been on scents that directly affect the behaviour of animals.
"For predators, food scents are particularly attractive, and much of this has to do with blood. We wanted to find out which chemical components create the scent of blood," he says.
The study found that for the animals, one particular component of blood odour was just as engaging as the blood odour itself: an aldehyde (called trans-4,5-epoxy-(E)-2-decenal), emits the typical metallic scent that humans associate with blood.
They wanted to test this scent with different predators, so half-metre long wooden logs were impregnated with four different liquids: lab-produced aldehyde, horse blood, fruit essence, and a near-odourless solvent.
The results were unequivocal. The logs containing aldehyde were just as attractive stimuli as those containing blood, while the two other logs aroused little interest. The commonest behaviours were sniffing, licking, biting, pawing and toying.
"It's a completely new discovery that raises interesting questions on evolution," says Prof Laska.
The study has been published in the scientific journal PLOS ONE.
La gente encuentra desagradable el olor de la sangre, pero para los animales depredadores dicho olor significa comida. Cuando los investigadores de comportamiento animal de la Universidad de Linköping en Suecia quisieron averiguar qué sustancias (de la sangre) provocan reacciones de comportamiento en animales depredadores, obtuvieron algunos resultados inesperados.....