This is exciting to read about. This was always, and is still, the only reasonable approach to curb overpopulation. Especially since reckless breeding has been allowed to flourish by the Koret models. All CA advocates need to support this in a big way.
Thank you, Hilary! I couldn't agree more—spay-neuter is the most effective and humane solution, and we need all advocates to rally behind this. The more support we generate, the better chance we have of making real change. Appreciate you being part of the push forward!
Thanks, Ed, for the mention of Fibonacci and the "70% solution," also known as "Get 70% or flunk." This is based on the concept that sterilization is in effect vaccinating animals against conception. 70% is the minimum number required to successfully vaccinate a population of any sort of animal against any contagious disease (it is easily possible to demonstrate why with a pair of dice), but more is always better. The late physics professor Robert Lewis Plumb of Chico State University, who doubled as president of the Progressive Animal Welfare Society in Chico, tipped me off to this in 1992, citing Fibonacci, & I have been speaking & writing about it ever since, often with Peter Marsh, in the context of approaching an animal population of unknown size, age stratification, and previous sterilization status.
In that situation, whether dealing with feral cats, as we usually are here in the U.S., or street dogs, the typical case abroad, the first step in planning an effective sterilization program is to count the numbers of cats or dogs. Then sterilize 70% within the first breeding season, and thereafter keep the sterilization ratio at 70% plus, for females essentially and for males preferentially.
Peter's disagreement with the "70% solution" is technical & usually inapplicable to real-life situations, but if you do happen to be able to identify the population of cats or dogs at large by age, he cites these considerations:
"The average age at which dogs or cats are sterilized greatly affects reproductive rates, too. A study of owned dogs in an Italian province found that if dogs were spayed at three years of age, 55% of the females would have to be sterilized to keep a stable population, but if the average age of sterilization was reduced to less than a year old, a sterilization rate as low as 26% could halt population growth."
Note that the above depends on also maintaining the mortality of dogs at the level found in that unnamed Italian province. Normally, though, an increase in the sterilization rate is accompanied by a decrease in mortality. Thus with no decrease in mortality, it might be possible to get away with sterilizing only 55% of the females, but reality is that in real life it is necessary to get the sterilization rate up to 70%.
Continues Marsh: "Another study found that 91% of the females in a feral cat population
would need to be sterilized to keep a stable population if cats were spayed when they were a year old but if females younger than that were spayed, too, a sterilization rate of about 71% would stabilize the population."
The error in that calculation is that if you wait until the cats your cohort are all a year old, of course you end up with more cats to fix to get ahead of population growth, whereas if you fix them all when you can catch them, at five or six months of age, "71% would stabilize the population."
As mentioned above, an easy demonstration of the need to vaccinate and sterilize 70% of a street dog and/or feral cat population can be done with dice, & I have often done it to conference audiences.
Throwing a pair of dice gives you 19 possible number combinations adding up to 11 possible totals. Designate the combinations adding up to 2-7 and 12 as immune or sterile (68%) and the rest as vulnerable to either disease or pregnancy.
Explain to your audience that you are now going to show them how far rabies can spread and how large the street dog and/or feral cat population can grow if 70% of the dogs are vaccinated. Ask for 10 volunteers to pretend to be 10 of the community s dogs and/or cats, to act out the demonstration as a skit.
Throw the dice 10 times, once for each person, to represent any random group of 10 dogs or cats who may be attacked by a rabid animal or may become pregnant.
If the dice show 2, 3, 4, 5, 6, 7, or 12, the dog or cat is sterilized and vaccinated. She will neither get rabies nor become pregnant. Have those volunteers step back.
If the dice show 8, 9, 10, or 11, the dog or cat has a litter, gets rabies, and can spread it.
Each time you get 8, 9, 10, or 11, ask for another volunteer to step forward from the audience, to represent the surviving offspring from the litter who may also breed and/or get rabies, and throw the dice again. Continue until all of your volunteers have stepped back.
Results will vary, but almost always you will end dog and cat reproduction and halt the rabies outbreak within fewer than 10 throws after your initial 10, which at the normal rate of street dog or feral cat mortality would be the replacement population level.
To check the results, you can decrease the numbers of immune combinations.
The importance of reaching 70% should soon manifest itself.
Dice. Don't leave home on a humane education mission without them.
Merritt, thank you for sharing the fascinating background on the "70% Rule." Your analogy using dice to illustrate the importance of reaching a 70% sterilization threshold is both creative and compelling when applied to real-world scenarios, particularly when dealing with feral cats and street dogs. Your explanation underscores the importance of setting ambitious targets for sterilization rates, especially when dealing with populations of unknown size or age stratification.
Thank you again for your contributions to this important discussion. Your and Peter Marsh's work has been invaluable in shaping my understanding of effective spay-neuter strategies.
Thank you! I signed the petition and also sent a note expressing that I wish there were an option to customize my signature with a story.
I recently met a woman who bought her dog on Craigslist. She later realized she couldn’t afford to neuter him in Los Angeles, so she waited until a trip back to her home state of Kansas to have it done. This highlights two major issues: first, the need for education about not buying dog's on Craigslist, and second, the lack of accessible, affordable spay/neuter services for people in her situation.
This is a real example of what’s happening in Los Angeles—and why this preventative funding will later save dollars caring for unwanted dogs.
Thank you, Bev! I really appreciate you signing and sharing this story—it perfectly illustrates why accessible, affordable spay/neuter services are so critical. Stories like this make the need for this funding even clearer. Grateful for your support in getting the word out!
Thanks Ed for this platform and reporting. This new media report may be slightly off-topic but another example of substituting a closely supervised meaningful volume s/n program for a "No Kill" charade-- labor and resource intensive transporting large behavioral dogs to "slow kill" or disposal destinations disguised as rescues or sanctuaries.
Arizona, already in chronic shelter overcapacity and overpopulation, was sent a reported 243 dogs from LA fires, mostly unaltered large dogs, pitts and huskies. Was this where many were shuffled from Pima Animal Care Center to a rescue who dumped them at this "sanctuary"?
The newly appointed Pima Animal Care Center director taking over from Best Friends trained Monica Dangler-- now with Outcomes Consulting, has since made deletions on the list of approved rescues he inherited.
There are many examples of such a pipeline exported from "No Kill" shelters.
Thanks, Carmen—I appreciate you sharing this. You're right about these transport schemes often serving as a smokescreen for failing local s/n efforts. Instead of real solutions, we get a "slow kill" shuffle that burdens other communities already struggling with overcapacity. The Arizona case is yet another example of why we need meaningful, preventative action—not more shell games. Thanks for keeping the spotlight on this issue!
This article addresses CRUCIAL solutions. If alleged Best Friends CEO Julie Castle's comment is accurate "we haven't figured out how to monetize spay neuter", with other evidence, strongly documents the ideological core of Maddies Fund, Best Friends permeating Cal Animals HASS and associated "consortium" that essentially abandons spay/neuter as core of "No Kill" was a deliberate overpopulation/shelter crisis strategy to monetize services for "the community as the shelter".
While introducing exponentially profitable proprietary databases (No Kill 2025 Best Friends Shelter Pet Data Alliance) control of national domestic animal welfare narrative.
This article is 1000% correct, allocating funds without strong administrative oversight only attracts grifters as evidenced by the vanishing/misallocated 50million allocation to UCDavis Koret that was utilized primarily to market an ideology thru Maddies Fund, Best Friends---promoting and perpetuating the overpopulation catastrophe. Most of those funds should be "clawed back" as illegitimately obtained.
A big pot of money attracts the self-promoters/grifters without administration and strong oversight and there are many examples as with San Bernardino, Ca 8 million allocated for dog park and spay/neuter that never materialized according to video of city council speaker's confirmed comment "where did the money go?". Animal welfare's critically needed spay/neuter programs are no exception. It's a choice: is accessible volume spay neuter with strong administrative oversight a priority with commercial breeding restrictions or submitting to third world stray population conditions (as Best Friends/Maddies Fund/ Outcomes Consulting advocates) mass euthanizing of domestic animal overpopulation and associated inhumane conditions depleting taxpayer and donor funds.
Carmen, thank you for your thoughtful and passionate comments. Your insights into the challenges facing s/n initiatives are invaluable, particularly your critique of how some organizations prioritize ideology over effective solutions. The need for strong administrative oversight to ensure funds are used effectively is a critical point, as evidenced by past mismanagement cases.
Your mention of the importance of prioritizing accessible high-volume spay-neuter services with strong oversight is well-taken. It highlights the choice between investing in humane, preventative measures and risking a continued crisis of overpopulation and euthanasia.
Thank you again for your engagement and for advocating for a more responsible approach to animal welfare.
This is spot on and we have a network of advocates here in GA. trying to ban together. It is quite disheartening to see how hard it is to get veterinarians and local officials to support the efforts.
This is exciting to read about. This was always, and is still, the only reasonable approach to curb overpopulation. Especially since reckless breeding has been allowed to flourish by the Koret models. All CA advocates need to support this in a big way.
Thank you, Hilary! I couldn't agree more—spay-neuter is the most effective and humane solution, and we need all advocates to rally behind this. The more support we generate, the better chance we have of making real change. Appreciate you being part of the push forward!
Thanks, Ed, for the mention of Fibonacci and the "70% solution," also known as "Get 70% or flunk." This is based on the concept that sterilization is in effect vaccinating animals against conception. 70% is the minimum number required to successfully vaccinate a population of any sort of animal against any contagious disease (it is easily possible to demonstrate why with a pair of dice), but more is always better. The late physics professor Robert Lewis Plumb of Chico State University, who doubled as president of the Progressive Animal Welfare Society in Chico, tipped me off to this in 1992, citing Fibonacci, & I have been speaking & writing about it ever since, often with Peter Marsh, in the context of approaching an animal population of unknown size, age stratification, and previous sterilization status.
In that situation, whether dealing with feral cats, as we usually are here in the U.S., or street dogs, the typical case abroad, the first step in planning an effective sterilization program is to count the numbers of cats or dogs. Then sterilize 70% within the first breeding season, and thereafter keep the sterilization ratio at 70% plus, for females essentially and for males preferentially.
Peter's disagreement with the "70% solution" is technical & usually inapplicable to real-life situations, but if you do happen to be able to identify the population of cats or dogs at large by age, he cites these considerations:
"The average age at which dogs or cats are sterilized greatly affects reproductive rates, too. A study of owned dogs in an Italian province found that if dogs were spayed at three years of age, 55% of the females would have to be sterilized to keep a stable population, but if the average age of sterilization was reduced to less than a year old, a sterilization rate as low as 26% could halt population growth."
Note that the above depends on also maintaining the mortality of dogs at the level found in that unnamed Italian province. Normally, though, an increase in the sterilization rate is accompanied by a decrease in mortality. Thus with no decrease in mortality, it might be possible to get away with sterilizing only 55% of the females, but reality is that in real life it is necessary to get the sterilization rate up to 70%.
Continues Marsh: "Another study found that 91% of the females in a feral cat population
would need to be sterilized to keep a stable population if cats were spayed when they were a year old but if females younger than that were spayed, too, a sterilization rate of about 71% would stabilize the population."
The error in that calculation is that if you wait until the cats your cohort are all a year old, of course you end up with more cats to fix to get ahead of population growth, whereas if you fix them all when you can catch them, at five or six months of age, "71% would stabilize the population."
As mentioned above, an easy demonstration of the need to vaccinate and sterilize 70% of a street dog and/or feral cat population can be done with dice, & I have often done it to conference audiences.
Throwing a pair of dice gives you 19 possible number combinations adding up to 11 possible totals. Designate the combinations adding up to 2-7 and 12 as immune or sterile (68%) and the rest as vulnerable to either disease or pregnancy.
Explain to your audience that you are now going to show them how far rabies can spread and how large the street dog and/or feral cat population can grow if 70% of the dogs are vaccinated. Ask for 10 volunteers to pretend to be 10 of the community s dogs and/or cats, to act out the demonstration as a skit.
Throw the dice 10 times, once for each person, to represent any random group of 10 dogs or cats who may be attacked by a rabid animal or may become pregnant.
If the dice show 2, 3, 4, 5, 6, 7, or 12, the dog or cat is sterilized and vaccinated. She will neither get rabies nor become pregnant. Have those volunteers step back.
If the dice show 8, 9, 10, or 11, the dog or cat has a litter, gets rabies, and can spread it.
Each time you get 8, 9, 10, or 11, ask for another volunteer to step forward from the audience, to represent the surviving offspring from the litter who may also breed and/or get rabies, and throw the dice again. Continue until all of your volunteers have stepped back.
Results will vary, but almost always you will end dog and cat reproduction and halt the rabies outbreak within fewer than 10 throws after your initial 10, which at the normal rate of street dog or feral cat mortality would be the replacement population level.
To check the results, you can decrease the numbers of immune combinations.
The importance of reaching 70% should soon manifest itself.
Dice. Don't leave home on a humane education mission without them.
Merritt, thank you for sharing the fascinating background on the "70% Rule." Your analogy using dice to illustrate the importance of reaching a 70% sterilization threshold is both creative and compelling when applied to real-world scenarios, particularly when dealing with feral cats and street dogs. Your explanation underscores the importance of setting ambitious targets for sterilization rates, especially when dealing with populations of unknown size or age stratification.
Thank you again for your contributions to this important discussion. Your and Peter Marsh's work has been invaluable in shaping my understanding of effective spay-neuter strategies.
Thank you! I signed the petition and also sent a note expressing that I wish there were an option to customize my signature with a story.
I recently met a woman who bought her dog on Craigslist. She later realized she couldn’t afford to neuter him in Los Angeles, so she waited until a trip back to her home state of Kansas to have it done. This highlights two major issues: first, the need for education about not buying dog's on Craigslist, and second, the lack of accessible, affordable spay/neuter services for people in her situation.
This is a real example of what’s happening in Los Angeles—and why this preventative funding will later save dollars caring for unwanted dogs.
Thank you, Bev! I really appreciate you signing and sharing this story—it perfectly illustrates why accessible, affordable spay/neuter services are so critical. Stories like this make the need for this funding even clearer. Grateful for your support in getting the word out!
Thanks Ed for this platform and reporting. This new media report may be slightly off-topic but another example of substituting a closely supervised meaningful volume s/n program for a "No Kill" charade-- labor and resource intensive transporting large behavioral dogs to "slow kill" or disposal destinations disguised as rescues or sanctuaries.
https://www.kold.com/video/2025/03/15/animal-sanctuary-southern-arizona-sparks-concerns/
Arizona, already in chronic shelter overcapacity and overpopulation, was sent a reported 243 dogs from LA fires, mostly unaltered large dogs, pitts and huskies. Was this where many were shuffled from Pima Animal Care Center to a rescue who dumped them at this "sanctuary"?
The newly appointed Pima Animal Care Center director taking over from Best Friends trained Monica Dangler-- now with Outcomes Consulting, has since made deletions on the list of approved rescues he inherited.
There are many examples of such a pipeline exported from "No Kill" shelters.
Thanks, Carmen—I appreciate you sharing this. You're right about these transport schemes often serving as a smokescreen for failing local s/n efforts. Instead of real solutions, we get a "slow kill" shuffle that burdens other communities already struggling with overcapacity. The Arizona case is yet another example of why we need meaningful, preventative action—not more shell games. Thanks for keeping the spotlight on this issue!
This article addresses CRUCIAL solutions. If alleged Best Friends CEO Julie Castle's comment is accurate "we haven't figured out how to monetize spay neuter", with other evidence, strongly documents the ideological core of Maddies Fund, Best Friends permeating Cal Animals HASS and associated "consortium" that essentially abandons spay/neuter as core of "No Kill" was a deliberate overpopulation/shelter crisis strategy to monetize services for "the community as the shelter".
While introducing exponentially profitable proprietary databases (No Kill 2025 Best Friends Shelter Pet Data Alliance) control of national domestic animal welfare narrative.
This article is 1000% correct, allocating funds without strong administrative oversight only attracts grifters as evidenced by the vanishing/misallocated 50million allocation to UCDavis Koret that was utilized primarily to market an ideology thru Maddies Fund, Best Friends---promoting and perpetuating the overpopulation catastrophe. Most of those funds should be "clawed back" as illegitimately obtained.
A big pot of money attracts the self-promoters/grifters without administration and strong oversight and there are many examples as with San Bernardino, Ca 8 million allocated for dog park and spay/neuter that never materialized according to video of city council speaker's confirmed comment "where did the money go?". Animal welfare's critically needed spay/neuter programs are no exception. It's a choice: is accessible volume spay neuter with strong administrative oversight a priority with commercial breeding restrictions or submitting to third world stray population conditions (as Best Friends/Maddies Fund/ Outcomes Consulting advocates) mass euthanizing of domestic animal overpopulation and associated inhumane conditions depleting taxpayer and donor funds.
Carmen, thank you for your thoughtful and passionate comments. Your insights into the challenges facing s/n initiatives are invaluable, particularly your critique of how some organizations prioritize ideology over effective solutions. The need for strong administrative oversight to ensure funds are used effectively is a critical point, as evidenced by past mismanagement cases.
Your mention of the importance of prioritizing accessible high-volume spay-neuter services with strong oversight is well-taken. It highlights the choice between investing in humane, preventative measures and risking a continued crisis of overpopulation and euthanasia.
Thank you again for your engagement and for advocating for a more responsible approach to animal welfare.
This is spot on and we have a network of advocates here in GA. trying to ban together. It is quite disheartening to see how hard it is to get veterinarians and local officials to support the efforts.