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World Spay Day - 2/25/2022

Updated: Feb 25, 2022

By John Bartlett

I've been in the Fostering community for over 10 years now, and have fostered well over 300 kittens, so I've seen the effects of not spaying. Sure, kittens are crazy cute and I just want to lay down and bury my face in a pile of them, but the kittens in rescue are the lucky ones. For every kitten in foster care, there's an untold number out in the wild fighting to live.

As such, spaying and neutering cats and dogs are important to me, especially if they're a pet. If I see a photo or video of your cat doing something funny and he’s got some big kahunas under his tail, I’ll likely sigh and shake my head. But if you’re reading this, you’re likely already on board, so I’m going to lean towards empowering you to make a more powerful argument for neutering and spaying to others.

People frequently state the benefits of spaying your cat before they give birth, such as improved health and lower chances of mammary cancer, but that really doesn’t mean much to someone who just got a female kitten. Especially when you’re talking about their health 15 years down the road. It might have more of an impact telling them how many litters she and her kittens may have over time. But even that can be hard to express because there’s not much consensus out there on it. I’ve found numbers between 420,000 cats in 7 years, to 2,072,514 cats in 8 years! And given that they all say something like “Each female will have an average of 4 kittens and half girls”, yadda yadda. The problem is that this kind of logic doesn’t match the real world, and people instinctively know this, which reduces your chance of convincing them using that line.

Even so, hearing that number may have them going “Wow” the first time they hear it, but then it breaks down to just another number that has little impact or meaning. You can imagine what one dollar bill looks like, but can you imagine what one million dollar bills looks like? A single dollar is something everyone has experience with, but very few with a million dollar bills in one room. But what if there was a way to help them visualize the number of cats one cat can have? That changes things.

What if I told you that an abandoned pregnant cat and her siblings can give birth to 407 cats in five years. You might think that’s not so bad from the numbers given before. But how would you feel knowing that 196 of those cats have died of various causes, and another 108 kittens were either stillborn or died before they were weaned? That might be harder to take. Now how about if I show you what that actually looks like?

The pictured simulation from the Cat Colony Simulator I created, is based on a ten-year study done on two cat colonies outside of Salisbury, UK, that spanned 1959-1968.

Try it out for yourself: Cat Colony Simulator - press F5 (refresh) to start a new simulation.

When I had the first version of the simulator working, I just sat there in shock as I ran simulation after simulation. Sometimes, the colony would die out after a year or two, but mostly it really exploded and just kept growing at an exponential rate.

The location of these colonies didn’t lend to high pregnancy rates, either due to the cooler temperatures along the 51st Parallel which doesn’t even touch the Lower 48 States of America. The simulator currently supports only one location at the time of this article, but development is in progress to allow you to manipulate the different factors to fit your own area. For example, a location in Southern Texas where kitten season really never ends, but also has more predators, which the UK really doesn't have many of.

The Simulator will display a maximum of 500 cats because browsers start to have trouble herding them, but you can still progress further in time. Note that if your colony starts to reach near a million, your browser may seem unresponsive as it tries to keep up and follow each one of those million cats going “Here kitty kitty”.

But I'd like to end this on a good note, so I'll include some photos of my past foster newborn kittens. If you're interested in the numbers behind the Cat Colony Simulator, I'll list them after the photos.

Rosemary and the Spice Kittens (pics)

Ripley's Kittens - also showing "Fever Coats" (pics)

The Clone Troopers (pics)

Gaia's Kittens (pics)

Salisbury, UK

Male Kitten: 49%

Female Kitten: 51%

Fail to wean (0-2 months old): 14%

Stillborn: 7%

Chance of passing at 3 months old: 20% (injury, malnutrition, predators, hostile cats, etc)

Chance of passing at 4 months old: 10%

Chance of passing at 5 months old: 5%

Chance of passing at 6+ months old: 3%

Litter Size Percentage

1: 3% 2: 9% 3:17% 4: 30% 5: 16% 6: 15% 7: 4% 8: 3% 9: 2% 10: 1%

The chance of a female getting pregnant has to pass both groups below

Chance of getting pregnant at 1-3 months: 0%

Chance of getting pregnant at 4 months old: 40% (reaching first Heat or impregnated)

Chance of getting pregnant at 5 months old: 60%

Chance of getting pregnant at 6 months old: 70%

Chance of getting pregnant at 7+ months old: 100%

Chance of getting pregnant by Month

Jan: 8%, Feb: 13%, Mar: 8%, Apr: 9%, May: 5%, Jun: 7%, Jul: 12%, Aug: 9%, Sep & Oct: 7%, Nov & Dec: 6%

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