Behavioral Responses to Mammalian Blood Odor and a Blood Odor Component in Four Species of Large Carnivores

Abstract

Only little is known about whether single volatile compounds are as efficient in eliciting behavioral responses in animals as the whole complex mixture of a behaviorally relevant odor. Recent studies analysing the composition of volatiles in mammalian blood, an important prey-associated odor stimulus for predators, found the odorant trans-4,5-epoxy-(E)-2-decenal to evoke a typical “metallic, blood-like” odor quality in humans. We therefore assessed the behavior of captive Asian wild dogs (Cuon alpinus), African wild dogs (Lycaon pictus), South American bush dogs (Speothos venaticus), and Siberian tigers (Panthera tigris altaica) when presented with wooden logs that were impregnated either with mammalian blood or with the blood odor component trans-4,5-epoxy-(E)-2-decenal, and compared it to their behavior towards a fruity odor (iso-pentyl acetate) and a near-odorless solvent (diethyl phthalate) as control. We found that all four species displayed significantly more interactions with the odorized wooden logs such as sniffing, licking, biting, pawing, and toying, when they were impregnated with the two prey-associated odors compared to the two non-prey-associated odors. Most importantly, no significant differences were found in the number of interactions with the wooden logs impregnated with mammalian blood and the blood odor component in any of the four species. Only one of the four species, the South American bush dogs, displayed a significant decrease in the number of interactions with the odorized logs across the five sessions performed per odor stimulus. Taken together, the results demonstrate that a single blood odor component can be as efficient in eliciting behavioral responses in large carnivores as the odor of real blood, suggesting that trans-4,5-epoxy-(E)-2-decenal may be perceived by predators as a “character impact compound” of mammalian blood odor. Further, the results suggest that odorized wooden logs are a suitable manner of environmental enrichment for captive carnivores.

Mammalian blood odorant and chirality: synthesis and sensory evaluation by humans and mice of the racemate and enantiomers of trans-4,5-epoxy-(E)-2-decenal

“…Further elution with hexane/EtOAc (30:1) gave 80 mg (3%) of (2E,4R * ,5R * )-(±)-1. Its IR, 1 H NMR and MS spectra were identical with those described for (±)-1 in Section 4.5. Further elution with hexane/EtOAc (10:1-4:1) gave 1.09 g of unidentified polar materials.…”

“…1) could be as efficient in eliciting behavioral responses among dogs and tigers as the odor of mammalian blood. 1 The fact that the metallic blood smell of 1 attracts predators is of interest in its ecological context to study the chemistry of how carnivores find their prey. 2 Nilsson et al, however, examined only racemic 1, which had been known since 1991 as one of the primary odorants in wheat bread crumb 3 and popcorn 4 by Schieberle et al Aldehyde 1 was found in many other food systems 5 such as black tea, 6 and its biogenetic pathway was speculated.…”

SNP genotypes of olfactory receptor genes associated with olfactory ability in German Shepherd dogs

“…As one of the mammalian prey species, dogs may have been more sensitive to a human odor compared to non‐prey‐associated odors (Nilsson et al . ). Furthermore, the interaction between certain genotypes and a certain odor was found for the OR10H1‐like: c.632C>T, OR10H1‐like: c.770A>T, OR4C11‐like: c.511T>G and OR4C11‐like: c.692G>A loci ( P < 0.01) (Table S6).…”

Synthesis of disparlure and monachalure enantiomers from 2,3-butanediacetals

“…(6R,7S,2E)-6,7-Epoxy-2-nonenal has been identified as a sex-aggregation pheromone of the red-necked longhorn beetle (Aromia bungii) [5] and its synthesis has been recently developed by Mori and co-workers [6,7]. (2E)-trans-4,5-Epoxy-2-decenal is present in mammalian blood and may be used by predators to track their prey [8,9]. A classical example of cis-epoxides with semiochemical activity is the chemical communication system of the gypsy moth (Lymantria dispar) and the nun moth (Lymantria monacha).…”