I recently learned about a similar use of animals for assisting humans:
In about 1915, he tried a more natural approach to control the street lighting in Brightwater – chicken power. They didn't have time switches in those days, so he connected a switch to the perches in his chicken house. When the chickens started to roost at night the weight would turn the lighting on and in the morning when they got down off their perches, the spring switch would turn the generator and lighting off.
- "Tests were used to determine how much napalm an individual bat could carry, determining that a 14 g (0.5 oz) bat could carry a payload of 15–18 g (0.53–0.63 oz)..."
Similar ideas were (perhaps apocryphally) used in the medieval ages,
- "Olga then instructed her army to attach a piece of sulphur bound with small pieces of cloth to each bird. At nightfall, Olga told her soldiers to set the pieces aflame and release the birds. They returned to their nests within the city, which subsequently set the city ablaze. As the Primary Chronicle tells it: "There was not a house that was not consumed, and it was impossible to extinguish the flames, because all the houses caught fire at once."[22]"
There was a fringe-y program in WW2 run by Skinner to try to train pigeons to act as primitive guidance computers for glide bombs. It only got minor funding and AFAIK was never tested with actual birds in actual bombs but they were able to train the birds and it seems like it could have worked.
> During WWII, British Special Forces considered stuffing dead rats with explosives and dispersing them over Germany. They hoped that the Germans would gather the rats and dispose of them in industrial furnaces, producing tremendous explosions that would cause catastrophic boiler failures.
Which inadvertently proved it's own effectiveness when some of the buildings at the base being used for testing were burnt down because some bats flew outside the intended test range and roosted in random buildings. Pretty grizzly story and I'm glad it didn't go to wide spread adoption but that part has always been hilarious to me.
It was for glide bombs which don't free fall. They're, as the name implies, gliders so fly further from the release point and don't fall ballistically. No idea if they got as far as actually strapping the guidance device onto an actual bomb though to see if they would work under stress.
I believe it's still the case that the system where TSA swabs things and puts those swabs into a detector uses live bees in cartridges to sense explosives[1]
Sounds like bullshit. Time switches would be trivial as long as you had a clock, and clocks existed long before electricity. The idea that rigging a switch on a perch in a chicken coop would be easier or more effective than using a clock seems ridiculous.
Time switches can only roughly accommodate the changing time of dusk and dawn, and can't handle dark weather at all. Said otherwise: if you're trying to approximate a light sensor, a clock is a worse approximation than a live chicken.
Or to give a specific counterexample to "The idea that [a chicken could be] more effective than using a clock seems ridiculous": during a solar eclipse, a chicken may go in to roost, but it would have to be a pretty sophisticated (or broken) clock to handle that case. (I'm not saying that solving for the solar eclipse case is necessary or useful, just that it demonstrates the point.)
At that point, look out the window and flip the switch yourself. Then you don't have to worry about whether the clock is wound, the chicken is sick or dead, or any other anomalies
I believe mussels are now (2025) protecting more cities.
What is cool about Warsaw is the TAWARA-RTM (TAp WAter RAdioactivity Real Time Monitor.
"Warsaw as the first city in the world is protected by a comprehensive system that is capable to monitor in real-time radioactivity of municipal water and by an innovative spectroscopy system capable to identify any detected contaminants"
It's likely already planned, but testing for radioactivity in wastewater too would likely detect any released radioactive material that didn't impact tap water.
Some form of this is quite common. My town's water treatment plant uses fish. They have all of their automatic monitoring things, but they also have a school of fish in the water coming out of the last stage of the plant, just before releasing it. They keep an eye on the fish. If they die, they know there's a problem and shut things down.
On a tour, I asked the obvious question: isn't that a little late? By the time the fish are dead, haven't you released a large quantity of hazardous water? The response was basically a shrug and "it's better than nothing".
An article (in French) published this morning about the city of Paris monitoring the Seine River and just discovered DNA of three endengered mussel species. They also mention that there are ten times the number of fish species compared to 1960.
It's quite a creative approach. I have a question about it, though, as the person whose expertise is far from biology: how much time does it take for the species to adapt / evolve under the new reality?
For example, the city I live in has access to the sea. Which means that there are plenty of seagulls and another type of bird that looks similar but has a slightly larger size (not sure about its name). However, I can observe that many of them are searching for food not in the sea, but rather in the trash bins quite far from the sea, in front of McDonald's and other fast food places, where they can steal the food from the hand of the person leaving the building.
This gives me a hint that their behavior changed quite a lot due to the new conditions they live in. Is the same possible with the mussels that the "mussels are well known for clamping their shells shut when water quality is poor" fact might change within a short time? Or does it take generations to evolve like that?
You seem to be conflating evolution with learning. Seagulls didn't evolve to steal from trashcans, they learned to.
As for the main point of your question: the clams are replaced every so often, so they won't end up getting used to the city water and stop serving as a marker.
Valid question though, and the answer to what I think you wanted to know is >3 months:
> the clams are “paid back after three months of work by releasing them to a place from which they will never be caught again”. [---] this is done because they eventually become resistant to contamination in the water.
"seagull" isn't one species. Pedantic ornithologists will say there's no such thing as a "seagull" since the group is more correctly just called "gulls" and many of them are found very far from any sea, but everyone understands the term anyway.
There are many different species of gull, they vary a lot in size (and a decent amount in plumage). Great Black-backed Gulls (Larus marinus) have about a 165cm wingspan, Common Gulls (Larus canus) have about a 120cm wingspan, and Little Gulls (Hydrocoloeus minutus) only about 61cm wingspan! And that's just for a few of the 20+ gull species found in North America, there's even more variation worldwide.
So the other slightly larger gulls are probably just other gulls, of a different species. The genus Larus in particular has several species that are quite similar in plumage, e.g. Ring-billed gulls (≈122cm wingspan) and Herring Gulls (≈147cm wingspan) look quite similar in flight or from a distance.
Gulls are scavengers. They will hunt for themselves, but will also scavenge food readily. They're well known for stealing fish from other birds such as Ospreys, eating carrion, etc. They learn what they can eat from observing other gulls (their parents and flockmates), eating trash isn't an evolved trait separate from scavenging but instead a learned behavior of what to scavenge.
When I lived in Aberystwyth on the Welsh coast you could always tell a newcomer to the town because they'd eat outside without aerial cover. The herring gulls there are pterodactyl-like, massive and always watching for the slightest opportunity to fill their beaks. They're clever birds too, I've seem them work cooperatively to deprive some poor fresher of their lunch and hawks had little success in driving them away. I've actually come to miss them a bit having moved inland, I'm moving back to a city by the sea this year and I wonder how long that will last!
Depending on where you are, you may be thinking of the great black-backed gull.
I've just googled, and herring gulls are indeed the birds I was referring to here in Norway, good catch.
We have the same, actually, when tourists/guests of the city are easier targets. A few times I had to "defend" (mostly, by hiding) my lunch sandwich or bun as well, if I wanted to eat somewhere with a view over the sea. However, even a few kilometers from the sea, they can still be on a "hunt". Very interesting creatures!
A weird approach to bioaccumulation which gets worse the higher in trophic level you go. Things like clams and sardines have the lowest levels of mercury etc. Swordfish and big tuna the worst.
Historically, the mussels harvested for eating have mostly lived very near the shoreline, and in areas with higher-density human populations. So their diets contained enormously higher concentrations of civilization's myriad water pollutants, compared to big deep-water fish.
Mussels PCBs is 0.8-7 ng/g and albacore tuna is 100. Mercury looks similar. I do notice that sardines seem higher in PCBs than I would have expected but their mercury is low.
In about 1915, he tried a more natural approach to control the street lighting in Brightwater – chicken power. They didn't have time switches in those days, so he connected a switch to the perches in his chicken house. When the chickens started to roost at night the weight would turn the lighting on and in the morning when they got down off their perches, the spring switch would turn the generator and lighting off.
Via: https://www.theprow.org.nz/people/robert-ellis/
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