The ogre catfish: prey scooping by the auchenipterid Asterophysus batrachus
Jansen Zuanon and Ivan Sazima
aqua, International Journal of Ichthyology, pp. 15-22, Volume 10, Issue 1 – June 2005
The catfish Asterophysus batrachus (Auchenipteridae) has a huge mouth gape and is able to ingest very large prey. However, how it catches and positions such prey in its stomach remains unrecorded. We studied the predatory behaviour of A. batrachus under aquarium conditions and found a novel feeding mode for piscivorous Neotropical catfishes. Asterophysus batrachus uses its cavernous gape in a remarkable way, scooping up large unaware prey headfirst, then taking advantage of the fleeing response to further the prey’s advance into its stomach. Positioning of the prey results from additional escape movements into the very distensible belly of the catfish. The prey ends up folded in the stomach with its head and tail pointing towards the head of the predator. A fasting catfish occasionally takes in water, bulging its belly considerably (“belly ballooning”). After a while the fish expels the water entirely, along with a little mucus and a few small fragments of food. The wrinkled belly quickly regains its former shape. Because of its huge mouth, ability to swallow large prey and overall appearance, we name A. batrachus the ogre catfish.
Adriaens, D. 2003. Feeding mechanisms. In: Catfishes, vol. 1. (Eds. G. Arratia, B. G. Kapoor, M. Chardon & R. Diogo): 221-248. Science Publishers, Enfield.
Barlow, G. W. 2002. The cichlid fishes: nature’s grand experiment in evolution. Perseus Book Group, Cambridge, 352 pp.
Britski, H. A. 1972. Sistemática e evolução dos Auchenipteridae e Ageneiosidae (Teleostei, Siluriformes). Unpublished Doctoral thesis, Universidade de São Paulo, São Paulo, 169 pp.
Curio, E. 1976. The ethology of predation. Springer- Verlag, Berlin, 250 pp.
Ferraris, C. J., Jr. 1988. The Auchenipteridae: putative monophyly and systematics, with a classification of the neotropical doradoid catfishes (Ostariophysi: Siluriformes). Unpublished Ph.D. dissertation, City University of New York, New York, 229 pp.
Ferraris, C. J., Jr. 2003. Family Auchenipteridae (driftwood catfishes). In Check list of the freshwater fishes of South and Central America. (Eds. R. E. Reis, S. O. Kullander & C. J. Ferraris, Jr.): 470-482. Edipucrs, Porto Alegre.
Froese, R. & D. Pauly (Eds.). 2004. FishBase. World Wide Web electronic publication. www.fishbase.org. Helfman, G. S., B. B. Collette & D. E. Facey. 1997. The diversity of fishes. Blackwell Science, Malden, 528 pp.
Lehner, P. N. 1979. Handbook of ethological methods. Garland STPM Press, New York, 403 pp.
Lundberg, J. G. & M. W. Littmann. 2003. Family Pimelodidae (long-whiskered catfishes). In Check list of the freshwater fishes of South and Central America. (Eds. R. E. Reis, S. O. Kullander & C. J. Ferraris, Jr.): 432-446. Edipucrs, Porto Alegre.
Menezes, N. A. 1976. On the Cynopotaminae, a new subfamily of Characidae (Osteichthyes, Ostariophysi, Characoidei). Arquivos de Zoologia de São Paulo, 28: 1-91.
Reimchen, T. E. 1991. Evolutionary attributes of headfirst prey manipulation and swallowing in piscivores. Canadian Journal of Zoology, 69 (11): 2912-2916.
Royero, R. 1993. Notas sobre la capacidad de alimentacion del bagre sapo (Asterophysus batrachus), (Siluriformes-Auchenipteridae) y algunos datos sobre su distribucion en Venezuela. Acta Biologica Venezuelica, 14 (3): 69-73.
Sabino, J. & J. Zuanon. 1998. A stream fish assemblage in Central Amazonia: distribution, activity patterns and feeding behavior. Ichthyological Explorations of Freshwaters, 8 (3): 201-210.
Saul, W. G. 1975. An ecological study of fishes at a place in upper Amazonian Ecuador. Proceedings of the Academy of National Sciences of Philadelphia, 127: 93-134.
Sazima, C. & I. Sazima. 2004. Chirocentrodon bleekerianus (Teleostei: Clupeiformes: Pristigasteridae), a small predaceous herring with folded and distinctively oriented prey in stomach. Brazilian Journal of Biology, 64 (1): 165-168.
Wickler, W. 1968. Mimicry in plants and animals. McGraw-Hill, New York, 255 pp.