Fish Can Count!

Scientists have known for some time that fish can tell big shoals from small ones, but now they've discovered that they do so by counting:

'We have provided the first evidence that fish exhibit rudimentary mathematical abilities,' says experimental psychologist Christian Agrillo of the University of Padova in Italy, who made the discovery while studying a group mosquitofish (Gambusia holbrooki). [...]

His team first conducted a series of experiments to see whether a lone mosquitofish would prefer to join a shoal of between two and four others. Females preferred to join shoals that were larger by just one fish significantly more often; consistently preferring shoals of four fish rather than three fish, and consistently preferring shoals of three fish over those containing just two. This means the fish were clearly able to count up to four and demonstrates that fish have a rudimentary mathematical ability to visually count how many items are present if the number is small.

A second series of experiments revealed the fish’s ability to process larger numbers. The fish were not able to directly count over four, but they were able to distinguish between larger numbers if they differed by a ratio of 2:1. For example, the fish could distinguish between a shoal of 16, compared to a shoal of eight others. But they could not tell the difference between a shoal of 12 compared to a shoal of eight, a ratio of 3:2. This demonstrates that fish are able to visually estimate larger numbers - but not very accurately.

Although it doesn't sound much, it is actually on a par with the numerical abilities of monkeys and human infants between six and 12 months old, who are both able to visually count small numbers and less accurately estimate larger ones.

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Lo and behold! Fish CAN count! A new study recently commented on by the National Geographic shows that fish can in fact count as high as four. They gave the fish multiple exit options from a tank, with each exit marked with one to four shapes. The trick is, only the exit with four shapes opened. The shapes varied in size, shape and brightness, so the only way they could recognise the exit was to "count" the number of symbols. The results were not overwhelming, but the fish did choose the four symbol exit more often than by chance alone. Booya! Next time I go fishing, I'm going to use four lures instead of one.
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this doesn't prove fish can count...
look im all for understadning new thing in new ways..
but it doesnt mean they can count.
they can sense when more is not less. and lees not more.

but to say they are logistically "counting"..
come on...
they feel energy, safety in numbers, but they dont rationalize the number with a label ...
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