Originally presented as an episode of the television series: The nature of things.
Originally produced by: Asterisk Productions Ltd., ©1998; previously released in 1999.
Title from title frames.
Editor, Shelly Hamer ; music, Patrick Godfrey ; photography, Peter Walker, Ian Kerr, Cezary Colsut, John Whatton.
Description based on online resource; title from title frames (Docuseek2, viewed December 8, 2016).