Last week I was enjoying a very pleasant evening in St Andrews. The sky was clear, the last rays of sun were warming the beach, the sound of the sea was pleasanty resting my exhausted mind. On my way back from the beach I crossed a small car park and while I was peacefully enjoying this last moment of tranquility before returning to the center of the city, my visual detection module got activated by an unusual object. Automatically, and whithout my conscious awareness and consent, my attention got focused on an unexpected thing. Rapidly a close look at it revealed that I was examining the remains of a dead body. As this thought occured to me, my sherlock holmes module spring into action... who was he/she? why did he/she died here? what was the cause of the death?

To make this more concrete, I shot a picture of the crime scene.

First, well, as you can see I am not lying. Shadows are long, so it must either be sunset or sunrise and because sunrise is at 5 AM in this season in scotland, it certainly is sunset. Second, you can see the murder occured very recently, there is still some water inside the shell, remains of dead tissues and the two parts of the shell are close to each others. By now, I am sure your Sherlock module is arriving at the same question as mine at that time: how did this poor little guy got murdered in the middle of a car park, with all the potential witnesses?

First, we are not far from the shore, about a hundred meters, so it could be that the snail was just going for a walk when it was killed. But what would a sea snail be doing here, on a car park? it is unlikely a sea snail came here by choice isn't it? so it must have been forced to come here before being killed. Premeditated murder, the case was promising. I know of only two possible agents capable of premeditated murder: humans or animals.

Humans would probably be the most straightforward explanation... the scenario is the following: a child walks on the big rocks on the shore, spots the little snail and drags him by force to the car park. There, bored by her prisoner, she throws it on the ground and before the snail makes it back to the sea, a car squashes it. Investigation cleared! but... indeed, there is a big BUT... the shell's empty! If a car squash a snail, you don't get an empty shell. Conclusion? the poor guy has been eaten, on a car park, in front of everyone. That's even worse than a simple premeditated murder no? Now, it seems quite unlikely to be a human murderer because even the French don't eat raw snails... cooked it's ok, but raw its very gross. Animal murderer then? Probably. But in the same way that we eat at the table, sea birds eat their seafood on the beach, not in the middle of a car park--unless some food has been left there by humans, but in that case they don't bring their food with them. Can you imagine bringing your own food to a restaurant? Probably not. Further, seabirds such as gulls have strong beaks that can probably break the shell of small sea snails. I don't know, I'm just guessing but I was skeptical about the seabird guilt after having photographed one.

My Sherlock module was running out of attention gas... but I decided to stay for a while and look around for other crime scenes. I found none, but I realized crows were not solely scavenging the dustbin, they were also foraging on the shore. An idea was emerging... crows are well known for their intelligence and are known to drop food on the floor to open hard containers. A particularly stunning example of such behaviour can be seen in this video:

In this video, crows use traffic to open hard nuts. They drop the nuts on the road when the light is red for cars, wait till the light turns green for the car to crush the nuts and wait till it's red again to retrieve the food. Really impressive isn't it?

Now I had two different scenario... first the crow goes to the shore, finds a snail, brings it back and drops it on the carpark, then, either the fall breaks it directly or the crow waits for a car to crush it. I sat on a bench for a while, carefully watching the crows passing over the car park. After some time I finally saw a bird coming with something in its beak... drop it on the floor... fly straight to the falling place... peck at the shell, then take it and raise it again at about 10 meters and drop it again... finally, walks as if nothing had happen and leave the place without the slightest remorse. I went back at the place were the second drops occurred and found another dead body. Apparently the successive falls are sufficient to break the shell and the crows knows that. The case was closed, I finally found the culprit of St Andrews snail murders:

So, what's the connection between this story and cognition and culture you ask? Well, if you're going to visit St Andrews university where very good research on cognition and culture is done, go to the car park near the acquarium on a nice summer evening and watch out for sea snails falling from the sky! You'll get a live experience of Crow cognitive capacities.