Prey odors

A square field (80 x 80 cm), with a milk-glass floor, marked off in 5 cm squares, opaque walls and a clear Plexiglas top was used. Snakes were placed in an open-ended cylinder and placed in the middle of the apparatus and the snake was allowed 1 minute to adapt. The cylinder was lifted and the snake was allowed to explore the apparatus for one minute during which tongue-flicks were videotaped. No prey or prey odor was ever placed in this apparatus. 

Odors can have delayed and unexpected effects. Garter snakes, T. sirtalis, were presented with either live earthworm or mosquito fish, Gambusia affinis, in a screen-covered bowl for several days. One day after transferring the snakes individually to a box free of prey odors, they were tested with aqueous extracts of fish and worms on cotton swabs. Snakes exposed to fish odor attacked fish extract less, and those exposed to worm attacked worm odor less. This is interpreted as habituation with a possible switch to other prey. This also demonstrates that in any experiment with chemical cues an odor not experienced for 22 hours may still have an effect (Burghardt, 1992). 

Ferrets, Mustekfuro, acquire knowledge of prey odors as young animals. This search image is not modifiable at later ages (Apfelbach, 1973). 

Not surprisingly, much research in sharks, skates and rays has focused on the responses of sharks to human body odors. Human blood attracts sharks, while sweat does not, and urine was even slightly repellent (Tester, 1963). Practitioners use whale meat and mixtures of fish meal and fish oils as shark attrac-tants. In both carnivorous and herbivorous bony fish (Osteichthyes) smell deals with prey odors, social odors, and chemical stimuli in homing, and it is mediated by the first cranial nerve, the olfactory nerve. By contrast, taste serves in detection and selection of food and avoidance of toxic food, and it employs the facial, glossopharyngeal, vagal, and hypoglossal nerves. 

Table 12.1 Prey odors used by marine fish...

Timber rattlesnakes, Crotalus horridus, are ambush hunters. They assume the ambush posture after smelling prey odors. In the laboratory, these snakes recoil the front part of their body into the ambush posture after flicking their tongues... 

Shorebirds use their sense of taste when probing sand for food. The purple sandpiper, Calidris maritima, and the knot, Calidris canutus, forage much longer in jars that contain food buried in sand, or sand with an extract of food, than in jars with plain sand (Gerritsen etal, 1983). Table 12.3 lists the responses of various seabirds to prey odors. 

FIGURE 12.4 Skatole, a prey odor used by snakes. 

Numbers of visits to scent stations baited with fatty acid tablets or prey odor such as shellfish oil allows estimation of population sizes of free-living red and gray foxes, raccoons, striped skunks, river otter, bobcats, cottontail rabbits, and oppossums. However, Smith et al. (1994) showed that the numbers of raccoon visits to scent stations did not reflect the size of their population. 

Atema, J., Holland, K., and Ikehara, W. (1980). Olfactory responses of yellow fln tuna [Thunnus albacares) to prey odors chemical search image. Journal of Chemical Ecology 6, 457-465. 

Clark, L. and Shah, P. S. (1992). Information content of prey odor plumes what do foraging Leach s storm petrels know In Chemical Signals in Verteirates vol. 6, ed. R. L. Doty and D. Miiller-Schwarze, pp. 421-427. New York Plenum. 

Lopez, P. and Salvador, A. (1992). The role of chemosensory cues in discrimination of prey odors by the amphisbaenan Blanus cinereus. Journal of ChemicalEcology 18,87-93. 

Ferner, M. C. and M. J. Weissburg. Slow-moving predatory gastropods track prey odors in fast and turbulent flow. 7. Exp. Biol. 208, 809-819 (2005). 

Zimmer-Faust, R.K., O Neill, P.B., and Schar, D.W., The relationship between predator activity state and sensitivity to prey odor, Biol. Bull., 190, 82, 1996. 

Predatory Fish Responses to Prey Odors (Chemical Lures)... 

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