Giaquinto, P. C.Volpato, G. L.2014-05-202014-05-202005-12-01Acta Ethologica. Heidelberg: Springer Heidelberg, v. 8, n. 2, p. 65-69, 2005.0873-9749http://hdl.handle.net/11449/17731The pintado (Pseudoplatystoma coruscans) is a ferocious carnivorous catfish with evident cannibalistic behaviour; its nocturnal habits are related to its ability to use predominately chemical sensorial modalities. This study investigated whether the pintado distinguishes conspecifics of different body sizes using chemical cues, which may reflect different physiological conditions such as hunger or stress. Pintados were observed when receiving water conditioned by either larger or similar-size conspecifics. A control group consisted of pintados receiving unconditioned water. Twelve repetitions were used for each condition. Feeding-like behaviours were investigated in the receiver fish and showed that they responded only to the conditioned water. Furthermore, a higher frequency of responses occurred when the water was conditioned by a similar-size conspecific. Thus, it is concluded that pintados are able to recognize conspecific size by chemical cues related to size and that this ability contributes to the individual's decision making on whether to approach or to avoid the conspecific.65-69engchemical cuesdecision makingfeeding behaviourpredator-prey systemsizeArtigo10.1007/s10211-005-0001-3WOS:000233857900001Acesso restrito59867844357279800000-0003-4591-4415