My name is Saulius Simcikas. I am a researcher at Rethink Priorities. I currently focus on topics within farmed animal welfare. Previously, I was a research intern at Animal Charity Evaluators, organised Effective Altruism events in the UK and Lithuania, and earned-to-give as a programmer.

Wiki Contributions


EA Superpower?! 😋

…AND I SHOW YOU HOW DEEP THE RABBIT HOLE GOES is a great slatestarcodex story which explores what can be done with different superpowers. I'd take the black pill which on the face of it looks like low magic.

Buck's Shortform

I would also ask these people to optionally write  or improve a summary of the book in Wikipedia if it has an Wikipedia article (or should have one). In many cases, it's not only EAs who would do more good if they knew ideas in a given book, especially when it's on a subject like pandemics or global warming rather than topics relevant to non-altruistic work too like management or productivity. When you google a book, Wikipedia is often the first result and so these articles receive a quite lot of traffic (you can see here how much traffic a given article receives). 

Key Lessons From Social Movement History

While there may be some benefits to increasing issue salience, our case studies provide weak evidence that high issue salience can decrease the tractability of legislative change,[35] which is evidence against tactics that are aimed at increasing salience. This might be especially so if advocates are trying to push through unpopular policies.

Because the animal farming industry has a lot of political power in most countries, I feel that it is they who are likely to push through unpopular policies that benefit animal farmers financially but hurt animals. I may be wrong, but I don't think that animal advocates pushing through unpopular policies has much precedent. I'm not sure what leverage animal advocates could use to do that.

Looking for more 'PlayPumps' like examples

I don't know much about it, but this talk mentions how sending free second-hand clothing as aid has damaged local textile industry in some countries. Quick google reveals some articles like this that should talk about it in more depth (I haven't read them though). Also, this article came to my mind but it seems that no charity was involved so it probably doesn't fit your purpose.

saulius's Shortform

I think it is useful to think about something like this happening in the current world like you did here because we have better intuitions about the current world. Someone could say that they will torture animals unless vegans give them money, I guess. I think this doesn't happen for multiple reasons. One of them is that it would be irrational for vegans to agree to give money because then other people would continue exploiting them with this simple trick.

I think that the same applies to far future scenarios. If an agent allows itself to be manipulated this easily, it won't become powerful. It's more rational to just make it publicly known that you refuse to engage with such threats. This is one of the reasons why most Western countries have a publicly declared policy to not negotiate with terrorists. So yeah, thinking about it this way, I am no longer concerned about this threats thing.

Linch's Shortform

I think that all of us RP intern managers took the same 12-hour management training from The Management Center. I thought that there was some high-quality advice in it but I'm not sure if it applied that much to our situation of managing research interns.  I haven't been to other such trainings so I can't compare.

saulius's Shortform

Shower thought, probably not new: some EAs think that expanding the moral circle to include digital minds should be a priority. But the more agents care about the suffering of digital minds, the more likely it is that some agent that doesn’t care about it will use creating vast amounts of digital suffering as a threat to make other agents do something. To make the threat more credible, in at least some cases it may follow through, although I don’t know what is the most rational strategy here. Could this be a dominant consideration that could make the expected value of moral circle expansion to be negative for negative utilitarians? Because the intensity and the scale of purposefully created suffering could outweigh the incidental suffering that would be prevented in other scenarios by an expanded moral circle.

EDIT: I no longer think that this is a legitimate concern, see my comment below.

Are mice or rats (as pests) a potential area of animal welfare improvement?

I just want to mention that UK government has just released Action Plan for Animal Welfare which has the following paragraph:

"We will also look to restrict the use of glue traps as a means of pest control to help make sure rodents are despatched in a humane manner. Glue traps can cause immense suffering to rodents and other animals that inadvertently fall victim to their use."


Insects raised for food and feed — global scale, practices, and policy

I’ve noticed a slight inaccuracy in this article (I’ve already discussed it with Abraham and he agrees that it is an inaccuracy). 

> Global fishmeal production was 15.8 million tonnes in 2014 (FAO 2016). As an example, we might reasonably expect insect meal to replace 25% of global production, or 3.95 million tonnes.

The source does claim that “In 2014, fishmeal production was 15.8 million tonnes” but I am now certain that this claim is misleading because in another place it says “Almost all of the remaining 21 million tonnes was destined for non-food products, of which 76 percent (15.8 million tonnes) was reduced to fishmeal and fish oil in 2014”. This page claims that 15.8Mt of fish were caught to produce 4.7Mt of fishmeal. And other sources like this also claim that fishmeal production is about 5Mt. The question is which number is more relevant. I think it’s the smaller one. Abraham said that the model uses the dry weight of insects, which should be closer to the protein / oil weight than to the total full body weight. I imagine that the conversion ratio between insect dry weight and insect protein is not 1:1 but I don't know what it is.  The guesstimate model assumes that the conversion ratios of fish to fishmeal and the dry insects to insect protein are the same but they are probably not. I think it follows that  insects replacing fishmeal would require fewer individuals.

From what I read, insect protein would not be replacing fishmeal, but it would likely be an additive that has some health benefits for fish and allows producers to claim that they are sustainable. I'm not sure it would lead to more sustainability, as they would probably continue to produce as much fishmeal as it's possible to produce without totally depleting the oceans at an even faster rate (I think fishmeal production has been constant). And fishmeal is likely to remain to be cheaper than insect protein. What insect production might allow is continued growth of fish farming because now the growth might be limited by the amount of available protein feed. 

In general, Rethink Priorities has done more research on this topic since this article was written but it's not published. If anyone is interested in doing anything about insect farming, please contact us, and we can share our new research. There are also some other new sources on this topic, like this report (it's written by a major investor into insect farming though so might be biased).  This and other similar reports predict insect farming to grow really fast.

Finally, note that Rethink Priorities is hiring an Executive Director of the Insect Welfare Project who will see what (if anything) should be done about the welfare issues explained in this article. Please apply if you think you are suitable or share with whoever you think is suitable. And we've just hired an entomologist (insect expert) to look into welfare issues and how they could possibly be mitigated. 

Ah, this comment is all over the place, but I have little time and I thought that writting an unorganized update would be better than nothing.

Rodents farmed for pet snake food

An owner of many snakes wrote to me about this article about some inaccuracies. I corrected the article in some places based on what they said. In this article sources on many questions were very poor so it didn’t take much evidence for me to change my opinion. I thought I would also just paste the relevant bits of the email conversation about this (with their permission), in case anyone else was interested in looking deeper into this cause.

Snake owner:  I read your article on rat/mice farms and how the quality of life is bad. Thats not true for some rodent farms but i believe most cases its true. i totally agree with banning all chain stores from selling exotic repitles including snakes. I personally own abandoned snakes from owners. I read your estimates for feeding snakes and its completely wrong. An adult ball python on average eats 1 medium rat every month! Not every week u will make it sick and die. second the corn snake was correct 1 large mouse every 14 days. Your boa one was soo far from reality. As a baby you feed them every week but an Adult eat 1 rat per month!! Any more offten and you are going to make your snake so obesse it will die! So please do your research! I work with a few rescues and do volenteer work on education on exotic snakes and parrots. My personal goal is to educate and make aware how hard to truely care for these animals are, so when i see a well writen and honest document that you wrote up for the welfare of animals that blaitenly ignores basic feeding guildlines to make insaine number for how much these animals eat takes away from your message. Please update your paper with the corrections of feeding quantites. On top of that adult BOAs and adult Ball Pythons only eat once a month dont always eat every month. Most ball pythons go on hunger strikes that can go as long as 1 years without food. So in actual fact you estimate a boa eats 12 rats per year the ball might only eat 8

so Yah your feeding numbers are totally far fetched. Also many other animals eat rats like tegus, savana monitors, hedgehogs eat pinky mice, most lizards.... so its not only about snakes.

Me: Thank you for your message about my article about rodents fed to pet snakes. I am the author of that article but I am by no means knowledgeable on the subject. My numbers of how many animals it takes to feed were based on a couple of hours of googling and are based on sources that are linked. So I agree that they are likely to be off and it would be good to make them better. 

> An adult ball python on average eats 1 medium rat every month! 

Your boa one was soo far from reality. As a baby you feed them every week but an Adult eat 1 rat per month!! 

For ball pythons, my sources are this, this, and this. Each of these sources indicate that they are fed more than one rodent per week. For Boa Constrictors, this page says “Once boas near adulthood, they will thrive while being fed every 10 to 14 days. It is okay to feed your boa more or less often” Could you please tell if you think that these websites are wrong, or if maybe I am misinterpreting them somehow? Also, this page and some other pages indicate that for example, instead of feeding one medium rat, you can feed 2 small rats, or 4-5 adult mice. Do you know if snake owners often choose to feed more smaller rodents instead on one big one? Because that might inflate the numbers.

> Most ball pythons go on hunger strikes that can go as long as 1 years without food.

Interesting, I didn’t know this. Could you tell how snake owners usually react to this? Do they still try to give them rodents every week? If yes, what happens to uneaten rodents? 

The only figure that matters for the final estimation is my guess that on average pet snakes are fed 31 to 94 vertebrates per year. This includes snakes of all ages and species. And this also includes vertebrates that snakes don’t eat who are discarded (if they are actually discarded). If you could tell what figure do you think I should use here instead of 31 to 94 vertebrates per year, that would be very appreciated and I would adjust my model accordingly. Do you think it should be 20? Or 10?

Snake owner: Thank you so much for contacting me on this subject means a lot that you want to get more accurate feeding numbers.

The ball python sources are correct you would be going on the adult feed schedule since they up the feeding quantities very quickly as babies. They grow fast and hit adult in approx. 2 years. They hit their full weight is 3 years but are usually eating their adult food size in 2 years. So, you would be basing the feeding amount on every month Approx. 28-56 days. At that weight if it’s a female 1 medium rat (approx. 4-5 foot) if it’s a small male 1 small rat (approx. 2.5-4 foot) The article is wrong on one point Ball pythons only eat rats since it has a higher fat content. Its also bad to feed multiple rodents over 1 rodent since they get more nutrients out of 1 rodent vs 2 smaller ones.

The boa article is extremely wrong and doesn’t give actual rat size per snake weight. is a much better feeding guide but it does mix up BCC vs BCI. BCC are common boas they only get up too 6-8 foot on average for females and the BCI are true red tail boas they are kept wilder and can often get 8-14 feet for females. Most owners have a BCC boa since they are much easier to handle. In the article it mentions baby-adult and I would recommend quoting the adult feeding since their adults’ way longer (30 years like ball pythons). A boa needs a large to extra-large rat every month or longer as adults they need a bigger meal rather then small meals and less frequently due to the fact, they expand their heart during feeding and require a longer time for the heart to return to normal size. If you feed to frequently you ‘power feed’ this reduces the life span by 15 years. Boas NEVER refuse food and tend to be obese.

For snakes that go on hunger strikes a lot of owners will either have multiple snakes and dethaw less rodents and feed the picky ones first and own a snake that always eats to eat the unwanted ones. If you have one snake you’re trying to feed once a month if the weight remains the same there isn’t any worry. Males go on hunger strikes during the mating season. This can be predictable but hard to judge. Most owners will continue to feed the non-feeding snakes once a month and the uneaten rodents are thrown away since you can’t refreeze them and risk being sick. I personally know friends with tegus that can eat rotten food, so I save them and give them away. For your article assume they are tossed.

There are also milk snakes, corn snakes, king snakes that are the most popular snake in north America. They only eat mice since they need a higher calcium food then a higher fat. These snakes eat more frequently and eat 1 large mouse every 2 weeks. They don’t refuse food and are commonly found obese. They are one of the easiest snakes too keep and commonly labeled as beginner snakes. is a good food reference for these snakes since they are almost identical in feeding and care. These snakes belong to the colubrid family, which is the largest snake family in the world, they also include hognose and are commonly active during the day. A good reference is if the eyes are round, they are daytime active like us. If the eyes are slitted, they are active during the night like cats. These snakes live 20 years on average the rest mentioned tend to live 30 years.

Hognose snakes are rising in popularity and males get to 1.5 foot on average and females reach 3 foot on average. They eat once every 2 weeks but only eat mice. They can be picky eaters, in the wild they eat frogs and toads and are mildly venomous. They rarely bite and being rear fang venomous they require thawing on the prey for a while but to humans it’s a minor bee sting at best. is a good feeding reference for hognose. Again, hognose can be picky eaters I have mine not eat every once and a while, but I feed them to my corn snake but commonly a would assume they are tossed.

I personally owning 14 snakes, owing 5 species of snakes (children’s python, hognose, corn snake, ball python, and boa) will have to discard 1 or 2 rodents every 4 - 8 months due to only having one animal that eats the larger sized rat. [...]

I’m glad you are bringing attention to these rodent farms and the unethical manner they have in treating the rodents. I personally researched my supplier and found one that ethically treats their rodents and even sells the tamer ones as pets. They kill the rodents but gassing them with carbon dioxide to have a quick death. Also, I would investigate the other prey items such as chicks and rabbits. A lot of snakes prefer quail or small chicks as a food source over rodents and are usually housed in the same facility with the same mistreatment. Also, some people will buy the cheap wild undesired ball pythons and then feed these poor snakes to their larger snakes such as reticulated pythons or Burmese pythons. These massive snakes are commonly illegal in most places since they can regularly obtain 15 -20 feet. [...]

For feeding per year, I would not make a total for all snakes I would break it down to species and then mention that corns, kings and milk snakes meeting the most popular pet snake eating 24 invertebrates per year, and larger snakes eating over average 12. With the larger snakes having a higher waste of uneaten invertebrates per year. Mention that ball pythons notoriously going on hunger strikes having the highest waste of uneaten food, being that they are vastly becoming the most popular pet snake. You can also mention that most snake owners tend to own multiple snakes and that due to the morph popularity have the highest number of discarded snakes with the popularity of certain morphs falling out of popularity.

There is a lot of controversial topics in that, morphs, discarded snakes and owning snakes just based on colour quickly being abandoned.

Again, thank you so much for reaching out to me, I really enjoyed knowing that there is someone speaking out on behave of the massive number of rodents being killed. There is not only snakes but large lizards that greatly consume a vast amount of rodents like tegus or savanna monitors. I know being a snake owner myself looing the ability to own these amazing animals would be a crime but forcing higher regulations for the care of these rodents should be required. Plus trying to restrict numbers of snakes you can own should be also mentioned. I own 14 but only bought 5 the rest were abandoned or rehomed after a pathic 3 years (adult hood) since their cute baby snake is a boring adult or the novelty has worn off.

Me: [...] I already made some changes to my article but I would like to ask you a few more questions if that’s ok. 

1. The most important question I want to ask is this. Do you know at what age most mice and rats farmed for reptile food are killed? I know that it differs a lot, but I need an average for my estimate and I am very uncertain what that is. So if most mice and rats are killed for adult snakes, about how old are they at the time of slaughter?

2.  > "I would recommend quoting the adult feeding since their adults’ way longer (30 years like ball pythons)"

I remember reading somewhere that while snakes can live that long in captivity, many of them don’t due to mismanagement, and that a high proportion of them die after a couple of years. Do you know if there is any truth in that?

3. > "I personally researched my supplier and found one that ethically treats their rodents and even sells the tamer ones as pets."

This gave me an idea of a welfare certification scheme for rodents. Such schemes exist for animals farmed for human consumption, and I may ask those certifiers if they would be interested in something like this. Could you tell what is the name of the ethical supplier that you found?

4. > "Also, I would investigate the other prey items such as chicks and rabbits. A lot of snakes prefer quail or small chicks as a food source over rodents and are usually housed in the same facility with the same mistreatment."

I did mention chicks as a food source. I assumed that chicks that are fed to snakes are male chicks from the egg-laying industry, who are usually culled soon after hatching, as they can’t lay eggs and their breed is not optimized to be grown for meat. If I understand you correctly, you are saying that this is not the case, and that chicks are bred specifically for snake food, right? If that is the case, then I would also appreciate it if you told me how you know this.

Snake owner:

1.Thats a hard one to answer the average size is a medium so they havent reached full size so under a year i would assume im not great on rat ages. Most feeding guides say the sizes but idk the age. Large snakes eat large adult rats. Corn snakes large adult mice.

Average for ball pythons is a medium rat i would estimate under a year old since they arent even full grown.

2.  I would say the majority of snakes do live a full life since an extremely large amount of keepers are generally breeders and experienced owners. For example a new snake owner that window shops is more likely to buy 1. They are the most likely to abandon them. Then theres people like me i own 17 snakes now and most people with a large collection usally spend quite a bit of money on them. Just on speculation i would believe most snakes do enjoy a full life in spite of all the issues you hear. More dogs and cats are abandoned significantly more then any reptile by a massive margin. The difference in snakes espically is they are villanized so they report EVERYTHING.

3.  The supplier i use is called CTC predator. They have top quality. If you dethaw there rats and mice they dont have a smell really. If you dethaw an artic mouse (petsmart brand) they smell terrible and i wouldnt feed them to my snakes.

4. Im really not sure at all where they get the chickens but i assume there males. Most rats are males aswell


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