Thirst for Blood
Carnivores FINDthe smell of an aldehyde, trans-4,5-epoxy-(E)-2-decenal, as attractive as blood. In a study at a wildlife park in Sweden,four predators-Asian wild dogs, African wild dogs, South American bush dogs and Siberian tigers-were exposed to the scent of four different liquids put on wooden logs: lab-produced aldehyde, horse blood, fruit essence and a near-odourless solvent. The animals were equally attracted to the logs containing blood and aldehyde, one of the components found in blood, while the other two logs aroused little interest. The most common behaviours were sniffing, licking, biting, pawing and toying. The study's results can be used to stimulate animals in captivity and keep them fit.
Source
Down To Earth, December, 2014