Is the Loch Ness monster a giant eel? Scientists share new DNA evidence from Scottish lake

Weeks-long stake-outs. Sonar readings. Satellite tracking.

There's a long history of people going to great lengths to prove the existence of the legendary Loch Ness monster.

So far, none of the theories hold water. But a new hypothesis was just floated. It's backed by science and it puts a very different face on the elusive creature: Nessie might be a giant eel.

University of Otago geneticist Neil Gemmell and a global team of researchers came to that conclusion after testing the DNA from hundreds of water samples from Loch Ness, cataloguing the wildlife that lives Scottish lake's murky waters.  

As It Happens host Carol Off spoke to Gemmell about the research and whether he thinks a giant eel is lurking in the depths of Loch Ness. Here is part of their conversation.

Have you come any closer to solving the mystery of the Loch Ness monster?

We've certainly got new evidence that tells us that some of the theories that have been put forward to explain the monster and the monster myth seem less likely than others.

We've done a very comprehensive survey of Loch Ness using environmental DNA.

So we don't need to capture sea creatures. We just need to be able to get water samples that have been in close proximity to those organisms to collect small particles that they've shed that we can then collect, concentrate and sequence, and compare to international databases to figure out what species are present.

So you've been trying to find out all the different species and animals that have had some contact with Loch Ness. What is the one that you think is most likely to perhaps explain the sightings people have had over the years?

The prevailing wisdom was that there were maybe four key hypotheses, and we tested each one of those.

There's the theory that there is an extinct giant creature here, maybe a giant marine reptile. We find absolutely no sequences that match with that sort of organism. In fact, we don't even find any reptilian DNA in our samples. So that's not something we have any strong evidence for.

And we tested a number of large fish — so catfish, sturgeon. We didn't find any evidence of that.

But we did find an awful lot of DNA from eels.

Now, one of the ideas that had been put forward, right from the 1930s onwards, was that the Loch Ness monster might be some form of giant eel, or at least some of the sightings were certainly explained that way.

It's still a long stretch to say from eel DNA that we've got a giant eel. But it's a lot more compelling than some of the other evidence that's been put forward.

Do you have any idea how big eels can actually get? I mean, if there is a giant eel, how big might it be?

A European eel is normally maybe four, possibly even up to six feet, in length. Some of the eyewitness reports here are of creatures that are 12, 14, maybe even 25 feet, in length.

Now, I don't think there's an eel that's ever been caught that's that long. So I guess there isn't a heck of a lot of direct evidence to support this notion. But it's something we can't rule out completely.

Are there any eels anywhere in the world that may have migrated and found themselves, just by happenstance ... into the stream and end up in Loch Ness?

I don't think we've got any evidence that there have been eels from other places. Although invasive species turn up in all sorts of other parts of the world.

The biggest freshwater eels that I'm aware of actually come from my homeland in New Zealand. So we have a species called the longfin eel and that can grow to six or eight feet in length. They can be as thicker than a man's leg. So they are quite large animals and they can live 50 to 100 years.

Of course, this goes back many years, doesn't it? Maybe even 1,500 years when people thought there was a beast in the River Ness. But this idea, since the 1930s, has got currency because people claim to have photos that proved to be not real. There were hoaxes, all kinds of things. How big is the idea that there is a monster in Loch Ness? 

There are people who are definite believers. They have very strong views on the presence of a monster. There are some who are adamant that there is some form of large, mysterious, reptilian-type creature.

And there's more than a thousand people who have documented seeing the monster. In fact, in the last year alone, there's been about 14 accounts.

There's also a relatively strong group of sceptics.

My personal view is that I don't think there is a monster. I think most of this is explained by natural phenomena. But I'm open to the idea that there may be things out there that we don't yet understand.

And so that's why we do this. But, you know, we're also documenting the biodiversity of Loch Ness, and in a new way, providing a lot of data on what fish species are here and what other things are here.

Fundamentally, it's a science project that just happens to have a very attractive piece of bait, which is the monster that has garnered enormous attention.

Among the many explanations people have offered over the years, there's one theory that it might be swimming circus elephants that escaped from the circus in Inverness [and] have found their way in there.

They've been swimming for a long time.

So you found no elephant DNA?

No, there's no elephant DNA. 

Another one of my favourite explanations is I got this letter in the mail from a guy who told me that it was mounted commandos that were on camels in wetsuits and it was a special task force to deal with problems in the Middle East.

What other theories have you heard?

There's lots of people who will say that we've missed Nessie because Nessie was on holiday.

Nessie is an extraterrestrial so it doesn't have DNA.

Nessie, of course, is some sort of fantastical creature, some sort of magical creature, so it doesn't have DNA.

Or, and this is getting into the realms of sort of Stargate, there is some kind of wormhole in space time and that effectively Nessie is some sort of Jurassic Cretaceous-age creature that just pops in and out existence here, every now and then.

People who want to believe in monsters will, and I think there's something in our DNA that makes us want to question our environment and also just interpret it in slightly unusual ways. I kind of like that.

I'm also open to the idea that there might be things out here that we don't yet understand.

Written by Kate Cornick and John McGill. Interview produced by Kate Cornick. Q&A has been edited for length and clarity.