麻豆淫院

(麻豆淫院Org.com) -- Researchers from Murdoch University believe a recently documented method of fishing may be spreading throughout a population of dolphins.

Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Shark Bay were photographed engaging in 鈥榗onching鈥� in 2007 and 2009.

The dolphins would trap small fish in large conch shells with their rostrums (beaks), then bring the shells to the surface and shake them, causing the water to drain out and the fish to fall into their mouths.

Murdoch Cetacean Research Unit Researcher Simon Allen says this previously rarely witnessed phenomenon might be on the increase, suggesting that the technique is spreading.

鈥淚n the last four months alone, the research team have seen and photographed the behaviour no less than six times, possibly even seven.

鈥淚f 鈥� and that is a big if 鈥� we are witnessing the horizontal spread of this behaviour, then I would assume that it spreads by an associate of a 鈥榗onching鈥� dolphin closely observing the behaviour and then imitating it,鈥� Mr. Allen said.

鈥淚t is a tantalising possibility that this behavior could spread before our very eyes 鈥� over a field season or two 鈥� and that we could track that spread.鈥�

The prospect of observing a learned behavior spreading through a population over a short period of time is exciting in itself, but the behavior also raises new questions about how exactly dolphins engage in conching.

鈥淎s yet, we don鈥檛 know if dolphins simply pursue fish into the 鈥榬efuge鈥� of the large, empty conch/bailer shells or whether they actually manipulate the shells prior 鈥� perhaps turning them over so that the opening is facing up in order to make them 鈥榓ppealing鈥� to fish as a place to hide from the jaws of death,鈥� Mr. Allen said.

鈥淚f we were to set up a few shells 鈥� opening down 鈥� in a known location and either witness dolphins turning them over, see evidence of them having been turned over when we weren鈥檛 around, or better still get some video footage of dolphins manipulating them in some way, then that would be priceless, since that implies forward planning on the dolphins鈥� part.

鈥淚 wouldn鈥檛 be too surprised to find such cunning and devilish ploys being adopted by Shark Bay鈥檚 bottlenose dolphins.鈥�

Until such observations are recorded though, Mr. Allen says it is too early to rush to any conclusions.

Members of the Murdoch Cetacean Unit, with colleagues from the University of Zurich, spend roughly four months of the year studying western Shark Bay鈥檚 dolphin population in the field.

The Unit operates with the assistance of a partnership with Shark Bay Resources, who provide accommodation, office space and mess facilities for the research teams.