"Filipino Monkey" is a pseudonym used by radio pranksters in maritime radio transmissions since at least the 1980s, especially in the Persian Gulf. These pranksters make odd, confusing, or even threatening calls on VHF marine channel 16, which is the shipping and maritime International Emergency Distress Frequency. All ships at sea are required to monitor the channel, which is meant to be used only until contact is made during an emergency, at which point the users are supposed to change to a different frequency..
An account of U.S. operations during Operation Earnest Will in the Gulf in 1988 contains this description of the Monkey's nighttime broadcasts:
"From time to time, the radio squawked, breaking the quiet with a burst of static. Most of the messages were fully routine, the expected traffic in a crowded sea. But every so often a high manic voice would break from the speaker: 'Hee hee hee! Filipino Monkey!' No one knew who the caller was, or what he meant by his strange message." 
 Iran-US naval incident of January 2008
On January 7, 2008, the government of the United States of America reported that the day before a number of Iranian IRGC Navy speedboats had harassed and threatened US warships traveling through the Strait of Hormuz (a narrow passageway between the Persian Gulf and the Gulf of Oman). In a video clip  released by the administration, a crew member on one particular warship was heard speaking the following on a communications radio.
"This is coalition warship. I am engaged in transit passage in accordance with international law. I maintain no harm. Over!"
This is followed by more footage of a number of smaller speedboats traveling at high speed around a number of US warships while the same crew member is heard speaking on the radio, warning five unidentified crafts that they were approaching coalition warships and asking them to identify themselves and report their intentions. Later the crew member is heard warning the crafts to stay away before a heavily accented voice is heard replying:
"I am coming to you... You will explode in... minutes."
The US administration used this incident - which occurred three days before President Bush was due to travel to Israel and Arab states of the Persian Gulf for talks on the Israeli-Palestinian relations, US arms sales to the Gulf Arab States, and US's claim that Iran was a dangerous nation with intentions of producing nuclear weapons (see Nuclear program of Iran) - as a good example of irresponsible, provocative, and aggressive behavior of the Iranian government , with President Bush warning that "all options are on the table to secure" US military assets