14

article from 2007:

Police in Iran are reported to have taken 14 squirrels into custody - because they are suspected of spying.
The rodents were found near the Iranian border allegedly equipped with eavesdropping devices.
The reports have come from the official Islamic Republic News Agency (IRNA).
When asked about the confiscation of the spy squirrels, the national police chief said: "I have heard about it, but I do not have precise information."

some articles:   

• http://www.jihadwatch.org/2007/07/iranians-arrest-14-squirrels-for-spying.html
• http://www.nowpublic.com/squirrels_arrested_iran_spying