Now they're hooked on Twitter.

“A group of baboons has learned to discriminate real English words from non-words just by looking at them written down,” according to a report in the New Scientist.

In a study conducted by Jonathan Grainger and colleagues of the University of Aix-Marseille, France, six captive Guinea baboons were trained to look at letters on computer screens.

Sometimes the baboons were shown a real, four-letter English word, but on other trials they were shown a four-letter non-word. They had to press one of two buttons, depending on whether a word or non-word was shown, and were rewarded with food if they got it right.

After a month and a half of training, the baboons had learned dozens of words. One could reliably identify 308 words—an impressive feat of memory, but is not that surprising. “Most complex animals can learn to categorize objects into two groups, such as “leaves” and “rocks”, given enough training,” according to the report.

The surprise came later. After practicing for some time, Grainger’s baboons became much better at identifying real words that they had never seen before. “That means they had learned the rules that determine which letter orderings form real words, and could apply these rules to distinguish them from unlikely letter orderings,” according to the report, which continued:

The findings suggest that the brain mechanisms human children use when they first learn to recognise written words are evolutionarily ancient, and were co-opted when written language came along, around 6000 years ago.

Tecumseh Fitch at the University of Vienna in Austria says the ability to construct rules that help us categorise similar objects into groups may be widespread in the animal kingdom, although the animals would not have evolved it to deal with words. “I wouldn’t be surprised if pigeons could do this,” he says.

Reading is a recent cultural innovation, says Fitch, meaning there has not been enough time for humans to evolve specialised brain circuitry for this skill. So it makes sense that reading relies on visual abilities that came about a long time before written language, for a different purpose.

Oh come on,  pigeons can’t read.