The BBC has dismissed an incident where Director General Mark Thompson bit a journalist on the arm as "horseplay".
Mark Thompson was made director general last year
The story was revealed in a leaked e-mail between Jeremy Paxman and BBC World duty editor Anthony Massey.
Mr Massey told the Newsnight presenter it happened in 1988 when he worked with Mr Thompson on the Nine O'Clock News.
A BBC spokesman admitted the incident took place, but added that the "gossipy" e-mail was never intended to be made public.
In the e-mail - which was leaked to an internet site - Mr Massey told Mr Paxman: "I was standing next to him on his right and he was sitting reading his horoscope in the Daily Star (I always remember that detail).
"Before I could say a word he suddenly turned, snarled and sank his teeth into my left upper arm, leaving marks through the shirt but not drawing blood."
Mr Massey added he had originally wanted to take Mr Thompson through the disciplinary process.
A spokesman for the BBC said: "This was something that happened 17 years ago.
"It was intended as a joke and it was clearly taken in the wrong way.
"Neither Jeremy Paxman nor Anthony Massey intended this to be made public. It was a private exchange."