Olfactory discrimination ability of South African fur seals (Arctocephalus pusillus) for enantiomers

Abstract

Sammanfattning/Abstract:The sense of smell in marine mammals is traditionally thought to be poor. However, increasing evidence suggests that pinnipeds may use their sense of smell in a variety of behavioral contexts including communication, foraging, food selection, and reproduction. Using a food-rewarded two-choice instrumental conditioning paradigm, I assessed the ability of South African fur seals, Arctocephalus pusillus, to discriminate between 12 enantiomeric odor pairs, that is, between odorants that are identical in structure except for chirality. The fur seals significantly discriminated between eight out of the twelve odor pairs (according to p < 0.05, with carvone, dihydrocarvone, dihydrocarveol, limonene oxide, menthol, beta-citronellol, fenchone, and alphapinene), and failed with only four odor pairs (isopulegol, rose oxide, limonene, and camphor). No significant differences in performance were found between the animals (p > 0.05). Cross-species comparisons between the olfactory performance of the fur seals and that of other species previously tested on the same set of odor pairs lend further support to the notion that the relative size of the olfactory bulbs is not a reliable predictor of olfactory discrimination abilities. The results of the present study suggest that sense of smell may play an important and hitherto underestimated role in regulating the behavior of fur seals.

Olfactory Discrimination Ability of Asian Elephants (Elephas maximus) for Structurally Related Odorants

“…Pigtail macaques were able to score above chance level with 5 out of 6 enantiomeric odor pairs (Laska et al 2005), and honeybees discriminated the (+)-and (−)-forms of 5 out of 8 of the enantiomers tested here (Laska and Galizia 2001). South African fur seals discriminated between 7 out of 12 optical isomers above chance level (Kim et al 2012). The Asian elephants, CD-1 mice, and Sprague-Dawley/Long Evans rats, in contrast, succeeded in discriminating between 12 out of 12, 11 out of 11, and 3 out of 3 enantiomeric odor pairs tested, respectively (Rubin and Katz 2001;Laska and Shepherd 2007;Clarin et al 2010).…”

“…A "+" symbol indicates that the group of animals or subjects succeeded in discriminating a given enantiomeric odor pair, and a "-" symbol indicates failure to do so. mouse data: Laska and Shepherd (2007); human data: Laska (2004) and Laska and Teubner (1999a); squirrel monkey data: and Laska et al (2005); pigtail macaque data: Laska et al (2005); honey bee data: Laska and Galizia (2001); rat data: Clarin et al (2010) and Rubin and Katz (2001); fur seal data: Kim et al (2012) by guest on November 7, 2016 http://chemse.oxfordjournals.org/ Downloaded from olfactory receptor genes in the Asian elephant is not known. However, its closest living relative, the African elephant, has recently been shown to have 1489 functional genes coding for olfactory receptors (Suwa et al 2011).…”

Enantioselective recognition of menthol by mouse odorant receptors

“…Smells of l-and d-menthol can be distinguished by mice and other mammals. 11,[17][18][19][20] In this study, we aimed to identify ORs that differentially recognized l-and d-menthol in mice. Since mice have over 1000 ORs, rather than random screening, we adopted a functional cloning strategy 21) in which the target ORs could be isolated from the OSNs that innervated the menthol-responsive glomeruli.…”