Guide to Patagonia's Monsters & Mysterious beings

I have written a book on this intriguing subject which has just been published.
In this blog I will post excerpts and other interesting texts on this fascinating subject.

Austin Whittall

Thursday, February 4, 2010

Cryptid maths. Statistical probability of seeing Nahuelito.


If there is a creature in Lake Nahuel Huapi (Nahuelito), one may ask oneself: what are the chances that I have to get to see this lake monster?

Today we will address this question in a serious scientific manner (here is Austin the Engineer trying to hog the limelight).

To see the creature, you have to be in the right place and at the right time. So first of all you have to travel to Lake Nahuel Huapi and lodge in one of the two towns that were built on its shore. Then you’d have to keep an eye on the lake to spot it.

So, the right place/time means some sort of probability. Like asking what are the chances of drawing a nine of spades from a pack of cards?

Well, that is easy: 1 in 52 (there is only one nine of spades and there are 52 cards in the pack). Probabilty boils down to “probable cases out of possible cases”. In the previous example there is one probable case (one nine of spades) and 52 possible cases (52 cards in the pack).

But, in the case of a lake monster, what are the probable and the possible cases?

Statistics lets get the numbers straight

In the first place, we have to calculate the ammount of time that tourists spend by / on / looking at Lake Nahuel Huapi during their stay in the region. That is, their “lake exposure”. This would be the possible cases.

Then we have the probable cases: the actual sightings.

To be meaningful, we have to use the same time frame for both events. In today’s exercise we will take one year as a baseline.

Possible cases

To calculate the possible cases we need some hard facts, and the Argentine tourism statistics that are available at the website of the Federal Tourism authority, which despite being a bit outdated (2006) give us a good starting point.

The data is available for the two main towns that are located by Lake Nahuel Huapi, Using 2006 data for San Carlos deBariloche (from here on SCB) and Villa la Angostura (from now on VLA).

1. Tourists, national and foreign:

Place  visitors
SCB   698.094
VLA     79.321

We will round off both figures to 700,000 and 80,000 visitors for SCB and VLA respectively.

According to the same source, their average stay in days per visit, is 3,62 (SCB) and 3,26 (VLA). You would expect tourists to spend more time wouldn’t you?

2. Local population.

Then we have the locals, the inhabitants of both towns. They too can see the beast.

The information that the
2001 National Census
provides is the following (the data is for the whole district, but as most of the population is concentrated in the urban areas, we can assume the town to have all of it):

Place   Population
SCB    94.640
VLA     4.181

We can round of the total population to 100,000 inhabitants (not much at all is it? Remember, Patagonia has a very low population).

3. Now we must calculate the “exposure” time.

If the tourists and locals spent all day and night by the lake we could assert that they spend 24 hours a day exposed to the lake (home of the lake creature). But the situation is different, they spend much less time in contact with it because they sleep, eat in restaurants, work, commute, and do indoor activities.

How much time do the spend by the lake navigating on it during an excursion or looking at it from a window, beach or path, fishing in it, rowing, swimming, etc.?

This is going to be guess work, but will try to use some reasonable assumptions:

a. 25% of the SCB tourists do an excursion on the lake, with a duration of about 2 hours. For VLA we will consider no lake excursions. This will be our “excursion” time. Considering the ammount of vessels on the lake, and the length of time that the excursions take, this seems a reasonable conjecture.

b. All tourists spend at least 20 minutes a day gazing at the lake during their stay. (Fishing, trekking, sitting on a beach, looking out of a window on a bus, etc.). We will call this “contact” time.

With these two hypothesis we can whip out our calculator and get some figures:

Exposure in yearly man hours (not to be a sexist, I will say hour.person per year). Below are my calculations:

4. Tourists – contact and excursion times.

Excursion time:

SCB. 2 x 0.25 x 700,000 = 350,000 hour.person / year

Contact time:

SCB. 20/60 x 3.62 x 700,000 = 845,000 hour.person / year
VLA. 20/60 x 3,25 x   80,000 =  87,000 hour.person / year

Grand total 1,282,000 hour.person/year

5. Locals – contact time.

Local population don’t go on excursions, and they have other activites in comparison to tourists. They work, go to school, are indoors most of the time, many commute and may get a chance to take a look at the lake. Also they may spend some weekends by it (fishing, picnicking or during winter skiing and looking at it from Cerro Bayo or Catedral ski resorts).

I will assume that they spend 10 minutes a day for weekdays and 45 minutes for weekends in “contact” time.

That is 140 minutes a week or 20 minutes a day.

The figure for SCB and VLA combined is therefore:

20/60 x 365 x 100,000 = 12,167,000 hour.person / year

6. Final figure and comments.

The Grand total of locals plus tourists is 13,449,000 hour.person per year, which we can round it off to 13.5 million person.hours a year.

That is a lot of time spent by the lake. For one single person this would mean spending 1,541 years of uninterrupted time spent gazing at the lake.

Of course, it is mostly daytime exposure because most sleep at night, there are no nocturnal lake excursions and during the night, visibility is severely limited. So if the creature surfaced at night, it could hardly be noticed or detected.

Furthermore, most of the “exposure” activity would be concentrated along the accessible coastal areas of the lake (i.e. highway 237, 40 and 231) or in the urban areas of VLA and SCB and the routes of the boats doing the lake excursions (Llao Llao or Bariloche Port to Puerto Blest or to Isla Victoria and Peninsula Quetrihue). So, if the creature lived in more placid waters away from all the noise and fuss provoked by us humans, it would seldom be seen.

Which would be the lake areas less frequented (or seen) by people?

The following map shows a rough sketch of the lake and the main urban areas (pink), the roads (blue) the aquatic excursions (red) and the coast accesible or visible from roads, boats and towns (yellow).

nahuelito where can you be
Lake Nahuel Huapi. Where Nahuelito can be seen. Copyright © 2010 by Austin Whittall

That leaves only four likely areas for the beast to live without being sighted which I have marked with bright green outline:

- The lake to the east of Isla Victoria, between the Island and Huemul Peninsula.
- Tristeza Fjord, to the south west. A lonely and beautiful place indeed.
- The lake west of Quetrihue Peninsula.
- Machete Fjord , to the north west.
- Rincó Fjord above Machete.

We must bear in mind that many small boats with fishermen criss cross the lake and also go into these areas.

Having said this, let’s calculate the probability of seeing Nahuelito, Lake Nahuel Huapi’s mysterious creature.

Based on the published articles, we can consider that there are roughly 2 (two) sightings per year (reported) so that means that the probability of seeing Nahuelito (probable cases out of possible cases) is:

Sightings (probable cases) / time spent looking (possible cases)

Which is:

2 events/year / 13,500,000 hour.person / year = 1: 6,750,000

This is a very very low number. It means that you (one person) would have to spend, on an average, 6.75 million hours to see the creature.

That is 770 years.

Slim chances indeed.

For the optimist and the believers

Well, don’t despair, perhaps it does live in the secluded areas. Which are not too frequented by people.

If we calculated the hour.person for these areas, it would be quite a low figure.

And the odds would be greater. But how much greater?

Lets suppose fishermen go there. The fishing season lasts about 6 months. And perhaps there are 10 boats with 4 passengers in these areas every day during that period. They spend about 3 hours per day there.

10 x 4 x 3 x 180 = 21,600 hour.person / year.

With the same 2 sightings, the odds are now:

1: 10,800

Not too good, but better than before. It would mean that one person would have to permanently watch the lake for a period of 1.23 years.

Keep your hopes up. Being a random event, you may see Nahuelito on day one (but also it may happen on day 450, or even much later, so are the workings of chance).

Lets organize an excursion and scour the lake looking for Nahuelito. I’m serious about this; e-mail me let’s discuss the matter.

Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia

2010 International Year of Biodiversity

Copyright 2009-2010 by Austin Whittall ©

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