Cooperation in fish

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http://www.eurekalert.org/pub_releases/2006-12/plos-fc120406.php

 

Fishy cooperation

 

It is commonly thought that animals can be arranged along a ladder of

intelligence

a sort of modern-day Scala Naturae

with humans inevitably at the top, followed by our close relatives, the

primates, all the way down to fish and other slimy creatures. Over the

past decade, this ladder has been challenged by claims of high

intelligence and great social complexity in other animals. For example,

spotted hyenas establish hierarchies in which dominant females support the

rank contests of their daughters. Bottlenose dolphins form " political "

coalitions every bit as complex as those of chimpanzees. Caledonian crows

not only use tools in the wild, but also modify tools in the lab, an

ability once thought to define humans.

 

And now come the fish. In an article published today in PLoS Biology,

Redouan Bshary from the University of Neuch

tel and colleagues describe the astonishing discovery of coordinated

hunting between groupers (Plectropomus pessuliferus) and giant moray eels

(Gymnothorax javanicus) in the Red Sea. These two species make a perfectly

complementary pair. The moray eel can enter crevices in the coral reef,

whereas the grouper hunts in open waters around the reef. Prey can escape

from the grouper by hiding in a crevice and from the moray eel by leaving

the reef, but prey has nowhere to go if hunted by a combination of these

two predators. The article offers a description and accompanying videos,

such as the one showing a grouper and eel swimming side by side as if they

are good friends on a stroll. It also offers quantification, which is

truly hard to achieve in the field, of the tendencies involved in this

mutually beneficial arrangement. The investigators were able to

demonstrate that the two predators seek each other's company, spending

more time together than expected by chance. They also found that groupers

actively recruit moray eels through a curious head shake made close to the

moray eel's head to which the eel responds by leaving its crevice and

joining the grouper. Groupers showed such recruitment more often when

hungry.

 

The observed role division comes " naturally " to two predators with

different hunting specializations, and is therefore far simpler to achieve

than for members of the same species. Also, recruitment is quite common in

the animal kingdom

for example, primates have specialized signals to solicit each other's

support in fights. What is truly spectacular about this study is that the

entire interaction pattern

two actors who seemingly know what they are going to do and how this will

benefit them

is not one we usually associate with fish. This is probably because we

tend to develop cognitively demanding accounts for our own behavior and

believe that absent the same cognition, the behavior simply cannot take

place. It is very well possible, however, that our accounts overestimate

the amount of intelligence that goes into complex behavior. Moreover, we

have a tendency to underestimate the intelligence of animals at lower

rungs of the evolutionary ladder. In fact, it is the ladder idea itself

that is wrong. The best way to approach animal intelligence is from an

evolutionary and ecological perspective focused on the tasks that each

species faces in nature. In this regard, these two reef predators show us

that if it comes to survival, highly intelligent solutions are within the

reach of animals as different from us as fish. (Watch a grouper signal to

a giant moray eel resting in a cave by shaking its head in front of the

moray in this video.)

 

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Related video for press use:

http://www.plos.org/press/plbi-04-12-bshary.wmv

 

Citation: Bshary R, Hohner A, Ait-el-Djoudi K, Fricke H (2006)

Interspecific communicative and coordinated hunting between groupers and

giant moray eels in the Red Sea. PLoS Biol 4(12): e431. DOI:

10.1371/journal.pbio.0040431.

 

CONTACT:

 

Redouan Bshary

University of Neuch

tel

Emile-argand 11

BP 154

Neuch

tel, 2009, Switzerland

00-41-327-183-005

redouan.bshary

 

PLEASE MENTION THE OPEN-ACCESS JOURNAL PLoS BIOLOGY (www.plosbiology.org)

AS THE SOURCE FOR THESE ARTICLES AND PROVIDE A LINK TO THE

FREELY-AVAILABLE TEXT. THANK YOU.

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