Fish can count

Adult humans use a third counting mechanism, in which they verbally count much larger numbers. Yet as Agrillo points out: '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.' For example, speakers of the Amazonian language Mundurukú lack words for numbers beyond five. 'Their limits in quantity tasks closely resemble what we found in pre-verbal organisms such as fish!' says Agrillo.