Fish that counts found by scientists

London, Feb 26 (UNI) Ramanujan, Pythagoras and other great mathematicians would not have imagined that even a fish could count.

But according to Italian scientists, North American mosquito fish have the ability to count up to four.

Previously it was known that fish could tell big shoals from small ones, but researchers have now found that they have a limited ability to count how many other fish are nearby.

Fishes' numerical abilities were actually on a par with the numerical abilities of monkeys and human infants between six and 12 months old, who were both able to visually count small numbers and less accurately estimate larger ones, researchers said. Adult humans use a third counting mechanism, in which they verbally count much larger numbers.

''The most interesting thing is that fish performance is very similar to what is observed in adult humans who possess a very limited vocabulary for numbers,'' said researcher Dr Christian Agrillo from the University of Padua.

The team conducted a series of experiments and showed that the fish could distinguish between shoals containing one or two fish, two or three fish and three or four fish. They could not tell the difference between shoals of four or five.

''We have provided the first evidence that fish exhibit rudimentary mathematical abilities,'' the Daily Telegraph quoted Dr Agrillo as saying.

The results of the findings are published on the BBC's natural history site, loveearth.com.

A variety of animals, including pigeons, parrots, raccoons, ferrets, rats, monkeys and apes are to varying degrees capable of either counting, adding or subtracting numbers. Most need to be trained to do so.

UNI XC ARB ND1640