I can't reference a specific specimen as the largest, but I know there are a few in zoos and a couple in private collections that are in the 18 to 20 feet range. I don't know of any larger than this in captivity, however there could be, but there is also no shortage of exaggerated claims. Greens in the wild over 20 feet are rare, and those around 25 feet are probaly 1 out of 10,000 adult female specimens. While there may have been a few females in the wild in the last 100 years that approached 30 feet, I have serious doubts that there has ever been a female that actually broke the 30 feet mark.

Kelly