Bots used to try and keep Wikipedia accurate and relevant can be highly antagonistic, undoing each other's edits and engaging in 'fights' that could last for years.

Oxford Internet Institute and the Alan Turing Institute researchers studied how bots interacted with each other in 13 language editions of the website from 2001 to 2010, leading to sometimes unpredictable consequences. 

They found that the actions of Wikipedia's bots varied according to their cultural environments, with Portuguese bots the most challenging, and German ones the most civilised. 

They also found that bots triggered edits later than human editors, and engaged in protracted conflicts. Some conflicts only ended when a bot was taken out of action.

In many cases, the researchers reckoned, the bots came into conflict because they followed slightly different rules to one another, leading to questions about how they are designed and the effectiveness of Wikipedia's bot policy, which did not cover how bots interacted with each other.