Millions watch hoax Animal Planet documentary Mermaids: New Evidence

Last year, Animal Planet aired the docufiction special and grabbed the cable channel's best ratings since the death of Australian "crocodile hunter" Steve Irwin in 2006. So it is no surprise that last weekend, they returned to the ocean for .

What is surprising is that this follow-up special netted Animal Planet's largest audience ever - including some who thought they were watching the real thing.

About 3.6 million viewers watched the special, which claimed to have never-before-seen footage of mermaids in the Greenland Sea. Both specials were hoaxes, designed to look like real documentaries. But that did not stop people tuning in en masse to witness a fake investigation into a mythical creature.

This is in stark contrast to Animal Planet's usual fare, which includes such reality shows as and .

Animal Planet president and general manager Marjorie Kaplan said: "The phenomenon of has truly been a watershed - and a water-cooler - moment for Animal Planet. These extraordinary television specials have electrified, challenged and entertained television audiences and online fans alike."

Many on Twitter seemed to believe mermaids could exist, despite a lack of real evidence.