article_snippet.sent: Scientists have found that Halobatrachus didactylus makes five types of calls not only to attract a mate, but to warn off rivals too may be trying to swipe Scientists nesting site.
article_snippet.sent: The creature is well camouflaged so sound is the best way to get attention .
article_snippet.sent: The whistles vary according to the size of the fish, meaning that specific calls from larger specimens are particularly effective at deterring another fish from picking a fight and stealing a nest.
article_snippet.sent: To prove that 'boatwhistles' are used as a deterrent as well as for seduction, she team deflated the swim bladders of fish under anaesthesia, so that the creatures could still contract the creatures muscles, but were rendered silent.
article_snippet.sent: her team found that mute males were more likely to face intruders in mute males nests, suggesting that Boatwhistles are an effective warning siren.
article_snippet.sent: Boatwhistles are a cheap way to exclude intruders without engaging in a fight,Clara Amorim of ISPA University Institute in Portugal said.
article_snippet.sent: Seeing that a nest is occupied is not as effective as hearing that there is a male in the nest eager to defend a nest