10 August 2007

Why I am sceptical of Brenda's story

Science thrives on scepticism. Scientist do not accept a new claim, regardless of how mundane it may be, unless it is supported by reliable observational records, reproducible experimental results or a mathematical proof. Any claim must also conform with the known laws, such as the laws of thermodynamics, unless there is enough evidence in the form of reliable observational records, reproducible experimental results or a mathematical proof that a certain law can be broken under certain circumstances. That, however, doesn't happen very often.

Because of the sceptical nature of science, scientists always argue and disagree with each other. That is why at scientific meetings there is invariably a question and answer period after each presentation. The arguments, however, never end after the question and answer period, but continue afterwards. We stop each other in the hallways and says things like "I don't quite agree with what you said during your talk, because I have some evidence indicating that..." Then, the other person tells you, usually in a nice way, why your evidence is a piece of trash. Although there are occasional scientists who disagree with each other so much that they turn into intellectual enemies, most scientific arguments are peaceful affairs done over cups of coffee or bottles of beer and nobody gets hurt. And eventually, the disagreeing scientists find a common ground, somebody develops a new theory and science takes a short step forward.

As I emphasized in this post, being able to communicate with other scientists is a crucial element in being a good scientist. A person who gets offended from even the slightest criticism of his/her work or ideas, can't survive very long in science.

That introduction paves the way for the rest of this post. A dear reader who identified herself as Brenda left a comment after this recent post and told an interesting and, as far as snails go, an extraordinary story. But, I am sceptical of her story.

Here is the relevant portion of Brenda's comment:

[Someone in the Smithsonian's Mollusk Division] told me that the department had, in the late 1980s, reorganized their collection, and came across a set of snails that had been collected in the 1920s, which came from Italy. They had been glued to pages of cardboard, then stored for decades.

When the Smithsonian staff came across that collection in the 80s, they were surprised to find that two of the snails were actually still alive, and had apparently survived for the last 60 years on cardboard and glue.

The story has a happy ending. One of the staff members was planning a trip to Italy, and took the snails with her, to release in the region of their origin.

And here is why I am sceptical of that story:

1. I read an account of immobilized snails surviving in a museum before. It is an old story, really old. The oldest version that I know of is on page 102 of Harry Wallis Kew's The Dispersal of Shells* from 1893:


I suspect the story told by the person from the Smithsonian may have been a different version of Baird's "often quoted" story.

2. I don't think land snails can survive 60 years without food and water. Even if those snails had fed on the paper and the glue and somehow obtained water from the humidity of the air, they wouldn't have lasted 60 years. Snails don't live that long.

3. Even if the snails had somehow survived that long, the folks at the Smithsonian would not have bothered to return them to where they had come from. Instead, they would have mercilessly saved the snails in alcohol. I know that, because that's exactly what I would have done, because I have done it before.

If the reader (or someone from the Smithsonian) produces more supporting evidence, I will certainly reconsider her claims. But otherwise, I will remain sceptical.

I hope I didn't offend you, Brenda. And I hope you will continue to read this blog.

Acknowledgement: Tim Pearce and Ümit Kebapçi gave me ideas about writing this post. That was a rare occasion when I agreed with their suggestions.

here from Google Books.


Brenda said...

Rest assured that I'm not at all offended by your scepticism. I was merely relating what was told to me by someone whom I assumed knew.

The story of the Egyptian snails does indeed bear suspicious resemblance to the tale that was related to me. I do hope that the Smithsonian, which is supposed to be devoted to science, does not make a regular habit of misinforming the general public.

But tell me, please; have studies been done that indicate how long it is possible for various snails to remain in a state of estivation?

Frank Anderson said...

I'll bet snails can estivate for a really long time, especially desert forms that only rarely encounter damp conditions. I haven't looked into this at all -- what are the confirmed records for length of estivation? Are there any? I'd also like to know more about the metabolic rates of active, resting and estivating land snails.

David said...

A few freshwater mussels are known to estivate for a few years-Wendel Haag had a Uniomerus on his desk from when he found it until he finished his dissertation.

I'd expect normal life spans for pulmonates to be rather short, though species in extreme environments might live longer due to estivating much of the year (like the over 200 year old mussels in Scandanavia). 60 years is long, though representatives of unrelated phyla are thought to last longer (tardigrades, rotifers, etc.)