Sterilization is the Answer: Towards a Puerto Rico without Stray Dogs and Cats

Our fourth mass sterilization was on May 21, 2016.

Our twelfth mass sterilization was on April,  2017.

It has been said that one female dog and her offspring can result in 67,000 dogs in six years. Yes, that is the number: 67,000 in just 6 years. How do they get that number? Well, let’s just do an easy exercise to show you how is calculated. Let’s say one female dog has a litter of eight puppies.  Just to make things easier let’s say that half of those puppies are females and the other ones are males… and let’s forget about the males for a while (don’t worry; we will be back to them shortly). So, Year Number 1 we have five female dogs (the mom and her 4 daughters). Year Number 2 the same thing happens to all the females; they each give birth to four more females. So now we have 25 dogs (the first five and their 5 X 4 = 20 daughters). On Year Number 3 the number would be 25 + (25*4) = 125. The same calculation is done for the remaining years: Year 4 is 625 (125 + 125 X 4 = 625); Year 5 is 3,125 (625 + 625 X 4); and by Year 6 the number is 15,625. Pretty amazing, right? I know is not 67,000 but remember we did not consider the male dogs, plus some dogs can have more than 10 puppies in one birth. And usually a female dog can get pregnant twice a year and not once like we did in the exercise. The numbers are even higher for cats. Are you scared now?

Image Courtesy of Sheba's Fix (

Image Courtesy of Sheba’s Fix (

***To know how to get the 67,000 number click here

This is the reason why there are so many stray dogs and cats in Puerto Rico: the lack of spayed and neutered pets in the island. It was well explained in the production “100,000”, a documentary written and directed by Juan Agustin Marquez (available in youtube here) whose title refers to the 100,000 stray dogs estimated to be in Puerto Rico back in 2010. Now think, is 2017 so seven years have passed since that movie. And there were already 100,000 stray dogs. Can you imagine what is the number now?

Puppies are often abandoned.

Puppies are often abandoned.

But education is the key for improving any situation and today, more and more animal rescue organizations are focusing their efforts in educating people about sterilizing their pets. For a while, ARF of Rincon was focused in rescuing stray dogs and finding them homes, but we realized that we needed to do something else to really solve the problem of the overpopulation of stray dogs and cats. I like to compare it to a dog that is not housetrained: if you do not train the dog, it will keep doing its business inside the house and you keep cleaning the mess. But if you train the dog, then there will be no more mess to clean. That’s why we started doing mass sterilizations and why we hire the services of Dr. Jose A. Cruz, who comes to Rincón to sterilize approximate 30 dogs and cats in one day. Dr. Cruz, who was awarded the ASPCA Presidential Service Award (check out the emotional video here), offers low-cost sterilization procedures all around the island thanks to its mobile veterinary clinic.

*If you want to sterilize your pet in the next mass sterilization, send an e-mail to with your information (name, address, and phone number) and your pet’s information (name, cat or dog, age, and history of vaccines) to reserve your space. 

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