Tag Archive: Barbara Drescher

Monkey’s Uncle

(Submitted by Skepticality listener Brian Hart)

I’m taking college level courses at UCLA to complete my education. I was sitting, an hour before class, and reading in our Anthropology book, a chapter about primates. I had no idea there were so many species around the globe. Anyway, one of the Old World species I had never heard of before, the Vervet Monkey, native to Africa, was mentioned in the book along with it’s picture. The chapter I was reading was about sexual reproduction, populations, groups, etc.

I closed the book and headed on to my Anthropology class and put George Hrab’s skeptical show, The Geologic Podcast, episode #383. In the amusing segment called, Interesting Fauna, Geo started talking about a species of primate and it’s mating habits. Can you guess which species? Yep, the Vervet Monkey.

I’ll be a Monkey’s Uncle (or, I share about 96% of my DNA with my Monkey Uncle)!

Below are the extended notes provided by cognitive psychologist and statistician Barbara Drescher for use in Skepticality Episode 254.  Take a look and leave your comments below. Also, please be sure to listen to the podcast for our own hilarious commentary. Also, visit Barbara’s blog ICBS Everywhere, and Insight at Skeptics Society.

It’s a cute story, but there is absolutely no way to calculate the odds of this happening. It’s highly likely that the author would read about vervet monkeys in an anthropology book, but the likelihood of the topic being discussed on a podcast is a pretty difficult thing to quantify. George is not an anthropologist, zoologist, or any other profession that would be expected to talk about primates. He is a musician by trade and his podcast is about science and skepticism. There are many potential topics for his show and while monkeys certainly aren’t a strange thing to discuss, it’s not exactly a commonly-discussed topic, either.

I think we just have to tip our hat to nature for this one and accept that this is one of those funny, unlikely coincidences that we just can’t quantify.

That and thank the coincidence gods or the opportunity for endless puns about monkeys.


(Submitted by Skepticality listener Misty Wegman.)

First of all, I do not believe in horoscopes or any such nonsense but in this situation it makes the story better. Feel free to take it out if it gets too messy.

I was born on June 2nd and my dad was born on June 3rd. This makes our astrological signs “Gemini” or Twins. He is an identical twin. I gave birth to fraternal twins. He is a twin-twin and I am a twin that had twins.

It gets better. My Aunt (father’s-sister) had identical twins. My mother’s Aunt had fraternal twins too (which is where I got them from). After my mother divorced my father, she married the boy of boy/girl fraternal twins. So I have twin second cousins, twin cousins, 2 twin dads and I’m an astrological twin that had twins.

What are the odds of more twins being born in my family?

Below are the extended notes provided by cognitive psychologist and statistician Barbara Drescher for use in Skepticality Episode 000.  Take a look and leave your comments below. Also, please be sure to listen to the podcast for our own hilarious commentary. Also, visit Barbara’s blog ICBS Everywhere, and Insight at Skeptics Society.

Well, I would say that the odds of more twins being born might be pretty good, but not much higher than in anyone else’s family. Of course, one would have to define and learn quite a few things before even trying to come up with an actual number, including what is meant by “family” (siblings? offspring?) and the ages and intents of those involved.

But there are a few things to talk about nonetheless.

First, the author notes that two of the cases of twins are identical, and one case is a step-father. Identical twins occur as randomly as astrological signs and one has no blood ties to a step-father, so these factors are independent–they have no influence on whether twins will occur in a family. Fraternal twins, on the other hand, do run in families, as hyperovulation is a genetic trait, although one does not receive genes from aunts/uncles. If genetics are to blame, the author’s chances of having fraternal twins on a subsequent pregnancy is now double. In addition, the age of the mother is a factor–the older the mother is, the more likely fraternal twins will occur.

All of that said, fraternal twins can also be the result of fertility treatments. This introduces a controllable factor that can increase the odds of twins dramatically. If fertility treatments are involved, genetics can’t be blamed.

According to Babycenter.com and several other online sources, the most recent data shows about 1 in every 30 births today are twins (about 3.3%), with only a about 10% of those being identical. So, about 3 in every 1,000 births will be twins born under Gemini.

Having that many twins in a family depends on many factors such as the size of the family, but I do love the idea of introducing someone as a twin twin with twins (yes, I know author isn’t a twin herself, but I took some license).

Three Trendies

(Submitted by Skepticality listener Michael McClure.)

I’ve been working at Disney Animation now for more than 18 years. My son was 11 months old when I started my career at the mouse. He’s now a 19 year old sophomore in college.

We were working on Tarzan a year or so after I started at Disney Animation. I got to know the Artistic Coordinator on the show, a fellow Scot musician named Fraser. One morning he called Support (where I was working at the time), so I took the ticket and went to see him. I had brought in some of my slides in a sleeve (16 slides per sleeve) a few days earlier, because I had a shot of the composer on Tarzan, one Phil Collins. However, instead of the short-haired, balding Phil of the early ’80s, my shot was from a Genesis gig in 1977 at the San Diego Sports Arena, with hirsute Phil (long hair, beard and all!) decked out in the jersey of the farm hockey team from the town that he threw on for the band’s encore of the evening, singing his heart out in a pool of red light. I’d shot the picture 20 years prior, and of course hippie Phil would be relatively unrecognizable to most folks in the late ’90s. The Tarzan production admin folks put out a printed newsletter each week containing the goings on in production-land, and I thought it would be fun to put this picture of Phil into the newsletter, to see if anyone could guess who it was.


Phil Collins, San Diego Sports Arena, 1977 Genesis Concert

I brought the sleeve of slides with me to Fraser’s office, I pulled out the slides to show to him, to see if maybe my musical brethren could guess who the hairy man in the slide was.

Fraser held the sleeve up to the light, and he pondered the picture of Phil for a moment, but I saw his glance drift to one of the other slides in the sleeve. Fraser couldn’t guess who it was, and was amazed when I told him that it was a picture of Phil Collins, but he kept looking at a different slide in the sleeve. Finally, Fraser said, “Can I pull this slide out?” pointing at some random slide I had in the sleeve along with my Genesis concert pictures. I said sure, and he pulled out a picture I’d shot of some random people along Princes Street in Edinburgh, Scotland when I was there with the California Repertory Theater in the summer of 1980 for the Edinburgh Fringe Festival, a huge, yearly theatrical festival held in the city. Fraser inspected the slide very closely, and then looked me in the eye, and said, “This is my best friend Graham.”

“What? Really?”

“Yes. No doubt about it. This is Graham.”


“3 trendies”

Well, that was stunning right there. The picture, as you can tell, shows three trendies (as I wrote on the edge of the slide) whom I stopped on the street that sunny day in August of 1981, and asked in my California twang if I could take their picture. The girls were fine with it, but the boy in the shot was huffy. I think he was annoyed by this ‘foreigner’ bothering them, and showed that by being annoyed and petulant in the picture (but, he was still in the picture!).


The sheet of slides, showing where the two pictures were located.


The “P. Collins” slide

3trendiesSlide (1)

The “3 trendies” slide (dated SEP 80).

Fraser and I had a great can-you-believe-it moment about this, a good laugh, and then we went about our day.

Within 20 minutes, Fraser had called back down to my offices, asking for me. I went back to his office, where I found him, looking even more stunned. After seeing this now 16 or 17 year old picture of his Best Friend, shot by his Support Guy at Disney Animation, he just had to call Graham to tell him about it. So, he did. And things got REALLY weird.

Graham apparently picked up his phone and said hello to Fraser. Fraser explained about the photo, and Graham shrieked in his ear on the phone and hung up. I mean, Fraser said he really SHRIEKED at him, and then abruptly hung the phone up. That was it.

So, Fraser called him back.

Fraser got Graham back on the line, and after a few moments, he drew the story of the shriek and the ensuing hang up out of him. Graham was completely beside himself the entire time they were on the phone. But, in the end, it made perfect sense.

Graham told Fraser that just a few hours earlier THAT SAME DAY, he had had a conversation with his old friend — let’s call her Carol — the small brunette in my photograph. He was attempting to refresh her memory of their other friend — let’s call her Alice — the blonde in the picture. But, Carol wasn’t remembering her. She couldn’t quite place her. Apparently Alice had left Scotland not too long after I’d taken the picture of the three of them in Edinburgh, to marry the bass player of the Bay City Rollers, a then very popular pop group/boy band. She’d gone all the way to New Jersey to marry this guy, apparently. In any case, Graham was trying to remind Carol of this other girl Alice, when he said something to the effect of, “Do you remember when that Yank stopped us on Princes Street years ago and took a picture of the three of us?” hoping that would jar her memory. Maybe it did, or maybe it didn’t — I don’t remember that part. But, Graham hung up with Carol eventually, and then Fraser rung him up from the States soon after that call and said over the staticky international land line, “You’re not going to believe the picture I just saw of you and two girls on Princes Street from the summer of 1981…”

I think I would shriek, too.

Below are the extended notes provided by cognitive psychologist and statistician Barbara Drescher for use in Skepticality Episode 247.  Take a look and leave your comments below. Also, please be sure to listen to the podcast for our own hilarious commentary. Also, visit Barbara’s blog.

There are some factors that increase the probability that Fraser would recognize someone in one of the pictures, namely the shared interest in a genre of music and probably the artist. However, it’s a pretty amazing and impressive event. I’ll add that if I was in Graham’s shoes, I would probably shriek, too. These things are bound to happen from time-to-time, of course, so there’s nothing supernatural about it, but that wouldn’t keep my jaw from hitting the floor if this had happened to me.

(Submitted by Skepticality listener  Mark Gouch relayed to The Odds Must Be Crazy by Barbara Drescher.)

Here is the article (includes video) by Barry Wolf, WKYC.

Holiday & Seasonal

But how can we say this is unbelievable as they do in the article? Sorry, but I can’t help myself here…

The odds would be one out of 365 * 365 * 365, or about one out of 48.6 million births. With 7 billion people on the planet, odds are that this has probably happened about 143 times ( to living persons. many more to those in the past). So rare, fun, and interesting, but not unbelievable.

I believe it happened based on the evidence (their claim that it did, which is good enough).

Actually since everyone has to have a birthday, we can ignore the first birthday, that of the man or the woman. So the odds someone marries someone with the same birthday (date of the year) as them is 1/365.

Then the odds their baby has that same birthday would be 1/(365 * 365) or 1/133,225. So with ~7 billion people this probably happened 52,543 times to persons living on the planet now.

The error in the first calculation is that the date was selected first. That calculation is correct for any specific date, whether it is January 1st or July 4th, or March 15th, or July 22nd. Anyone with better knowlege of probability please correct me if any of the above is incorrect.

As often happens, things that seem unbelievable are quite believable and things that are believed without evidence are not believable.

Below are the extended notes provided by cognitive psychologist and statistician Barbara Drescher for use in Skepticality Episode 246.  Take a look and leave your comments below. Also, please be sure to listen to the podcast for our own hilarious commentary. Also, visit Barbara’s blog.

Good job!

You are correct with both calculations. It depends on how you frame it. If you’re wondering the odds of two people with the birthday of January 1st marrying and having a baby on January 1st, then the first is correct, but as you pointed out, that’s not really what’s interesting.

The only thing I would add is that these calculations also assume some things that we know are not true, such as that births are uniformly distributed across the days of the year. Even if natural births were (they aren’t), we’d see fewer births on days like January 1st simply because the number of scheduled C-sections and inductions is lower because it’s a holiday. However, figuring those few things in requires data that probably isn’t available.

Road Rage!

(Submitted by Skepticality listener Michael Farese.

I have less of a story and more of a question. My girlfriend is from New Jersey and has a very, um, animated personality. While driving, she often gives people certain gestures, honks, flashes headlights, etc.

I always tell her that she needs to be careful and that she shouldn’t do things like that because there are crazy people out there who might try to run her off the road (or worse) in a fit of road rage. She tells me that I’m being ridiculous and that she has a better chance of getting struck by lightning.

My question is: does she have a better chance of getting struck by lightning? Am I worrying about something that has only a negligible statistical chance of occurring?

Looking forward to some insight!

Below are the extended notes provided by cognitive psychologist and statistician Barbara Drescher for use in Skepticality Episode 243.  Take a look and leave your comments below. Also, please be sure to listen to the podcast for our own hilarious commentary. Also, visit Barbara’s blog.

Hmmm…. Well, finding statistics about road rage is difficult, mostly because the definition of “road rage” is fuzzy. However, after looking at several different sources, I believe it’s safe to say that it seriously injures or kills around 1500 people in the U.S. per year, and that doesn’t include incidents in which only minor injuries or property damage are involved.

By contrast, the number of people who are injured by lightning in the U.S. each year is fewer than 300. On average, the number killed is 33.

Several websites echoed this sentiment written in About News:

“Statistics tell us that most all of us have been involved in an aggressive driving experience either as the victim or the aggressor at some point in our lives.”

Yet the lifetime chances of being struck by lightning at some point in one’s life are about 1 in 12,000. So I’d go with the author on this one.

The Spooky Cab Ride

(Submitted by Skepticality listener Celestia Ward

Greetings. I had a strange coincidental experience a couple of decades back that, unfortunately, wasn’t cute or funny. My odds-must-be-crazy story is actually kind of gruesome and not for the weak of heart. So if you don’t mind a change of pace from your typical stories, I’ll tell you mine.

Some years ago, in Baltimore, I worked part-time with a small crew of artists in the tourist district. There were maybe eight of us. After night shifts I would routinely take a cab home; as a young female, waiting for a bus late at night could feel a bit lonely and dangerous. I would walk across the street to the large hotel taxi stand and usually there would be one or two cabs waiting.

One Sunday night I hopped into the one waiting cab and the driver told me he had just gotten paged by one of his “regulars” and would need to go pick her up–but if I wanted to ride along he’d drop me off afterward for a reduced fare. I had never had a driver offer this before, but there were no other cabs at the stand and a cheaper ride sounded good to me. I was in no hurry.

This regular client was a nurse who was just getting off her ER shift at the major hospital in the city center. We chatted as we rode, and she described the victim of grisly crime that had come in the previous night. An eighty-year-old woman had been attacked by her adult son, who lived with her and had a history of mental illness. He had come home from a drinking binge, accused her of stealing his money, and beat her up–even cut into her lips and cheeks, the nurse said, convinced, in his psychotic state, that she was hiding money in her mouth.

The cab driver and I were horrified. She said that the police had this man in custody and were expecting to charge him with murder. The old woman was in very bad condition and not expected to recover.

The nurse was dropped off at her house, then the cab driver took me home at his promised discount, and I just assumed that would be the last I heard of that awful scenario, unless the local news was covering it.

I went to work the next night and saw a couple of coworkers with grim expressions on their faces. They told me that Joe (I am changing his name) wouldn’t be working with us anymore. I first assumed that he’d finally been fired–Joe was kind of a jerk, had some issues and drank too much. No one really liked Joe.

It hit me sideways when my coworkers told me he had been arrested–for killing his mother! Out of the whole city, out of all the times I had taken a cab, I had ended up in the one taxi cab that–unknown to me at the time–got me a firsthand account of a murder committed by a coworker.

Tell me, what are the odds??!

Below are the extended notes provided by cognitive psychologist and statistician Barbara Drescher for use in Skepticality Episode 242.  Take a look and leave your comments below. Also, please be sure to listen to the podcast for our own hilarious commentary. Also, visit Barbara’s blog.

It’s hard to say what the odds are without more information. The population of Baltimore at the time would be helpful, but not entirely, since the odds are increased a great deal by geography–the proximity of Joe’s home to his work place and the hospital where his mother was taken are not coincidental. So, I can say that the odds are much higher than one might think, but it is still quite a coincidence, and similar to stories I have heard before (I even have a similar story myself).

It is a gruesome story, and that gruesomeness enhances the chill and eeriness of the coincidence.

(Submitted by Skepticality listener Charles Dahlheim

Back in the bad old days before bluetooth became common in automobiles people often used FM transmitters on their cellphones to listen to their music in their cars. These transmitters often used low FM frequencies and would override reception in nearby cars.

One day I was listening to a fascinating story about how some outstanding grade school science teachers were rewarded by being given a ride on NASA’s Vomit Comet. The teacher’s students had designed experiments for their teachers to perform under microgravity conditions and I was very interested to hear about their experiences.

Just as the story reached the part where the teachers were going to describe how it felt to be weightless, I suddenly heard music coming from my radio and Lionel Richie started singing “Ooo what a feeling, when you’re dancing on the ceiling”.

It’s a good thing I was pulled up at a stop light or I’d have driven off the road. The coincidence was awesome.

Below are the extended notes provided by cognitive psychologist and statistician Barbara Drescher for use in Skepticality Episode 238.  Take a look and leave your comments below. Also, please be sure to listen to the podcast for our own hilarious commentary. Also, visit Barbara’s blog.

Hahaha! Very cute.

The odds are not as crazy as people might think. Lots of music might have been funny in that situation. A line from Space Odyssey, maybe, or any line about floating or feeling. I can think of several off the top of my head, some more fitting than others, but all pretty funny, like “I’ve looked at clouds from both sides now”, “I can see clearly now”, “I’m hooked on a feeling, high on believing”, or “Up, up, and away”. And I’m sure there are many more that are even better.

But of course none of that reduces the humor of the story, and it was a low, if not crazy-low probability event.

Odds on Current Events

(Based on a link submitted by reader Sean Duncan)

The Independent Investigations Group, which as you loyal, dedicated, and detail-oriented readers know is a Los Angeles, California-based organization that investigates claims of the paranormal and pseudoscience, is affiliated with The Odds Must Be Crazy and provides a lot of our support and backing.

The IIG regularly receives all sorts of communication regarding a wide variety of topics, including requests for advice on how to handle unusual situations related to the IIG’s fields of expertise. In this case, listener Sean Duncan decided to write in and get the IIG’s assistance with a subject he’d been discussing with a friend. Here is that email:


My name is Sean and I live in Shelton, WA. I’m emailing because a skeptic of skepticism asked me about how, sometimes in disasters, thousands of people will die in a particular building yet one will survive for days or weeks because they are in the right place at the right time. I told this person that I would contact the Independent Investigations group because they like to calculate the odds of things. With so many people calling this phenemona a miracle, it might make for a good segment on The Odds Must Be Crazy. If you have the desire to calculate the odds of this Bangladesh woman surviving 17 days, we’d both appreciate it.




Through this communication a long discussion thread was started to address the question and build a complete picture of what would be required to answer it. We found the results really interesting, and have decided to share some excerpts with you below:

Comment by Barbara Drescher:

There is absolutely no way to calculate the odds of such a thing; it would require knowing everything about the building at the time of the collapse as well as defining the context (e.g., the odds of surviving, given that one is in the building when it collapsed, or the odds of it collapsing right when one is standing in that spot?).

How I would respond to such a question would be to ask more questions. If it is a miracle that she survived, then what is it that the other 1100+ people died? How many people do you think survived for several days, but died before they were rescued? Would it be less of a miracle if it was 15 days or more of a miracle if it was 18 days?

This kind of thinking is flawed because it is “post hoc”, or after-the-fact. Given what we know happening, the odds of that happening are 100% (because it already happened). Even if we predicted that a survivor or two would be found this long after, it’s still not remarkable because it happens. People will always be “in the right place at the right time” and “in the wrong place at the wrong time”. When we think about all of the circumstances that must be “lined up” for such a thing to happen, it looks remarkable, but something has to happen. Some set of circumstances is going to be the set that occurs. Someone will eventually win the lottery.

I’m reminded of the research that Hugh Ross did in which he calculated an outrageous probability that the universe would produce human beings. It was so outrageous that he concluded that it must have been an act of God. However that kind of thinking is exactly like asking someone to pick a number between 1 and 600,000,000,000, then being shocked by the number they picked, given that the chances of them choosing that number were 1 in 600,000,000,000.

Comment by IIG Chairman Jim Underdown:

It reminds me of two related issues. The question is like asking what are the odds of surviving a car crash. It depends on the car, the speed, the driver, what it hit – and countless other factors.

The post hoc example I like is the paint bucket that fell off a ladder. What are the odds it would produce exactly that spatter pattern? … 100%!

Comment by Jerry Schwarz:

It may be important to emphasize the difference between the probability that a specific person will survive for that long and the probability that one out of the thousands of people in the building will survive.  I suspect that many people don’t understand that difference.

Comment by IIG Steering Member Dave Richards:

The kind of statistics I have a real problem with are ones where there’s a bimodal or multimodal aspect. For example if you plot the ages of death for 10,000 individuals on a histogram, it won’t be a nice bell curve – there’s going to be a big spike in infancy due to childhood diseases, another spike in middle age from heart attack and stroke because that’s when those usually happen, more spikes from various cancers for people that outlive the other stuff, and then finally a spike when the body just finally gives out from old age. To boil such a spiky graph down to a single average age for longevity is pretty much a useless statistic. But this kind of thing is done all the time in news articles.

Jim Underdown responds:

I guess I’m arguing that because each car crash (plane crash, building collapse) is unique, and survivability depends on lots of factors dependent on that particular crash, making general predictions (or assigning odds) about someone surviving any such incident would be beyond the amount of useful information you’d ever have access to in a random event like this. The odds you’d come up with in your car crash statistics might easily be useless unless you added in lots of other controls like speed, car make, alcohol, etc. A sober person who never drives a Mack truck more than 20 miles an hour will be well beyond the insurance company’s risk tables. (Sort of along the lines of shark attack risk for those who never go near water.)

The correspondent is interested in whether we can assign odds to her having survived. There’s quite a difference between calculating the odds that someone would survive, and that this particular woman would survive.

Barbara Drescher rounds up the strategy of developing probability: 

Starting with a very specific question is essential and without one, it’s not even possible to guestimate.

And I think that’s the disconnect that people have when they think of these kinds of occurrences as miraculous (I don’t think it’s relevant whether they consider it an act of God or just a really amazing coincidence). Post hoc thinking has the luxury of being vague, but it’s not the vagueness that makes it bad.” And following up: “I just don’t see how that’s relevant. The question isn’t about how statistics are used. It’s about whether an event is extraordinary, probabilistically speaking.

IIG Steering member Spencer Marks adds:

… the way I read the question about the odds didn’t seem (to me) strictly a question about the odds of surviving the collapse of the building, but of the survivor living for 17 days. That question of course is ALSO not a matter of “odds,” but of many different environmental factors such as the ambient temperature, perhaps humidity, his availability to water, his general condition before the collapse … Like Barbara said, this is not a matter of odds but purely biological and physiological science at work, and that should be mentioned!

Bay Area IIG member Leonard Tramiel summarizes: 

There is a very good reason that the odds here are different. It’s related to the reason that it is considered a “miracle”.

It happens rarely. We can state the odds of being in a car crash because this happens many times every day. Surviving a building collapse for more than two weeks … not so common.

Given the poor statistics, we are forced to consider computing the statistics and that is hopeless for either building collapse or car crash.

Overall we found this was a rather interesting (you can feel free to disagree with us without hurting our feelings) look into the thought processes that sometimes go into analyzing stories like this.

We now return you to your regularly scheduled stories. There will be further interruptions.

(Submitted by friend of the blog, Spencer Marks)

A few years ago, I was driving home, and saw something moving in the middle of the street on the north end of the block that my house was on. When I got close enough, I realized it was a 12” California Desert Tortoise just walking down the middle of the street, in broad daylight, and in the middle of the city! Not wanting him (I knew it was male due to the “fighting fork” under his carapace) to get run over, I picked him up, and took him to my house. He seemed very comfortable around people, since when he would see someone approach, he would actually run toward the approaching person (well, as fast as a tortoise can run!), presumably to get fed. I figured he must have been hand-raised, since he had absolutely no fear of humans at all, and seemed to enjoy their company.

A month later, I was talking to a friend (one I didn’t talk to that often), about him coming to pick up some equipment from my house, and he asked for my address. As soon as I gave it to him, he said, “Oh wow … I grew up on that very street … just at the other end of the block from you!” We then talked a bit about who was in the neighborhood when he was growing up, and who still had a house there, and all of that sort of stuff, and for some reason he said, “I had a pet tortoise when I was a kid, and we couldn’t find it when we moved out, so I wonder if it is still at that house…”

I almost fell over! I told him that I had just found a tortoise in the street DIRECTLY in front of his old house the month before. He had moved away over 30 years prior to that, so I assumed it MUST have just been a different tortoise, but when he came to my house to pick up the equipment, he took one look at the tortoise, and said, “YEP! That’s him!”

I asked him if he wanted him back, and he said no, so today “Speedy” lives with me at my new house, with lots of places to roam, and spoiled with fruits and veggies by all who see him!

[EDITOR: We’ve all heard the crazy story of the dog or cat that manages to track their family ALL the way across the country to their new home (and seen plenty of movies about it, too). But it takes the brilliant staying power of a tortoise to stick around and wait 30 years for their family to return to them.]

Updated 4/23/2012

Below are the extended notes provided by Barbara Drescher for use in Skepticality Episode 181. Take a look and leave your comments below.

In most of the stories of coincidence we share, the proximity, time-wise, of two incidents is short, but it’s hard to be shocked by it. Given the number of people with which Spencer was likely to interact in the weeks following finding the tortoise and the likelihood that some of those people lived in that neighborhood at some time in their lives, interacting with the tortoise’s previous owner is less unusual than it appears. The tortoise coming up in conversation is not that unusual, either. Any mention of where Spencer lived was bound to spark a conversation about the fact that the friend once lived there and that topic is likely to spark memories of the pet left behind.

If the tortoise was an adult when it was lost by the friend, the odds were pretty good that he would still be there 30 years later. The three biggest questions that spring to mind are:

  1. What is the probability that the tortoise would remain in that location for 30 years without intervention?
  2. What is the probability that the tortoise would have been moved (or taken in and cared for as Spencer did) by someone during those 30 years?
  3. What is the probability that the tortoise would still be alive after 30 years?

That the probability that the tortoise would remain in that location is high is fairly obvious to most people, I would think. It would take a tortoise most of day to travel even a mile, so tortoises tend
to maintain a rather small home range. Being removed by a new resident or other human requires being seen. Despite his size, which is not insignificant, the tortoise managed to be lost in the first place (assuming it was an adult at the time). The species is known for borrowing, so it is highly likely that he dug a hole under the house and spent much of his life there, undetected. Raccoons, larger and more active animals, thrive in urban areas and are rarely seen by their human neighbors. What’s more, the desert tortoise lies dormant during colder months, reducing the amount of time it is visible even more. I also wonder how many people would even know what to do if they saw a tortoise walking across the road. Unlike Spencer, I would not have known the species or sex of the animal, nor would I know whether it was safe to pick it up. I might simply try to hold traffic until it was safely across the road, then let it be.

If they survive to become adults, the lifespan of a tortoise is similar to that of a human, so 30 years is not unusual at all. The tortoise’s survival, therefore, relied on its ability to find food and avoid predators. Since their diet is mostly grasses, we are left with predators as the biggest danger. More specifically, ravens and coyotes (since gila monsters, badgers, and foxes are rare in this tortoise’s location). If, as I’ve assumed, the tortoise was an adult when it disappeared, it is fairly safe from these as well. Ravens will eat tortoise eggs and juveniles, but the shell of an adult is usually too much work when other food is more readily available. Although there might be some overlap in the daily cycle of the coyote (which tends to retreat to its den when the sun rises) and the desert tortoise (which is most active in the first half of the day), again, the tough adult shell makes a tortoise less desirable than other choices. In short, the chances of surviving 30 years on its own are excellent, assuming (again) that the tortoise was an adult when it was lost. It’s actually quite small if it was very young. Only 1 in 5 survives to adulthood in its natural habitat.

When we consider all of the factors, the one which brings the probability of this incident down the most is the temporal factor – the order and proximity of the events in time. It is certainly considerably lower than the average participant’s chances of winning a football pool at their office. Still, it is much greater than that of my next door neighbor winning the California lottery, yet that jackpot is won by someone’s next door neighbor dozens of times each year.