What Happens When You Don’t Neuter Your Cats?What Happens When You Don’t Neuter Your Cats?

Year 4Year 4

Wow! That’s a lot of cats!Wow! That’s a lot of cats!But now I have a question…But now I have a question…

How did we come up with these numbers?How did we come up with these numbers?

And, what mathematical processes were used toAnd, what mathematical processes were used to

determine the population increase over the fourdetermine the population increase over the four

years? years?

• Addition? Subtraction? Multiplication? Addition? Subtraction? Multiplication? Division?Division?

Here’s the math…Here’s the math…

Year 1Year 1

1 female x 3 litters x 6 kittens= 18 kittens1 female x 3 litters x 6 kittens= 18 kittens 2 adult cats + 18 kittens = 20 total felines 2 adult cats + 18 kittens = 20 total felines ½ x 20 total felines = 10 females½ x 20 total felines = 10 females

Assuming half of the kittens born are Assuming half of the kittens born are female, and that females begin having female, and that females begin having kittens at 1 year old.kittens at 1 year old.

Continued…Continued…

Year 2Year 2

• 10 females x 3 litters x 6 kittens = 180 10 females x 3 litters x 6 kittens = 180 kittenskittens

• 20 adult cats + 180 kittens = 200 total 20 adult cats + 180 kittens = 200 total felines year 2felines year 2

• ½ (200 felines) = 100 females½ (200 felines) = 100 females

Continued…Continued…

Year 3Year 3• 100 females x 3 litters x 6 kittens = 1,800100 females x 3 litters x 6 kittens = 1,800• 200 adult cats + 1,800 kittens = 2,000 total 200 adult cats + 1,800 kittens = 2,000 total

felines year 3felines year 3• ½ (2,000 felines) = 1,000 females½ (2,000 felines) = 1,000 females

Year 4Year 4• 1,000 females x 3 litters x 6 kittens= 18,0001,000 females x 3 litters x 6 kittens= 18,000• 2,000 adult cats + 18,000 kittens = 20,000 2,000 adult cats + 18,000 kittens = 20,000

total felines year 4total felines year 4

How can we communicate these numbers?How can we communicate these numbers?

A diagram of cats (like the one we looked at A diagram of cats (like the one we looked at earlier) is one way to show the increase in cats earlier) is one way to show the increase in cats each yeareach year

But what if you do not have a computer, and there But what if you do not have a computer, and there are too many cats to draw?are too many cats to draw?

What is another visual representation of the cat What is another visual representation of the cat population numbers?population numbers?

Cat Population GrowthCat Population Growth

20 2002000

20000

02000400060008000

100001200014000160001800020000

Year 1 Year 2 Year 3 Year 4

Something else to think about:Something else to think about:What about the first 2 cats?What about the first 2 cats?

Together, the first two cats produced 45 kittens over the Together, the first two cats produced 45 kittens over the 4 years4 years

• 3 litters x 6 kittens per litter x 4 years = 3 litters x 6 kittens per litter x 4 years =

45 kittens45 kittens But indirectly, they produced a population of But indirectly, they produced a population of 19,998 cats19,998 cats, ,

in addition to themselves, since each of their female in addition to themselves, since each of their female offspring also had 45 kittens per yearoffspring also had 45 kittens per year

This doesn’t even include the number of kittens each of This doesn’t even include the number of kittens each of the male offspring can produce each year (potentially the male offspring can produce each year (potentially thousands!)thousands!)

Now it’s time to apply this concept to a Now it’s time to apply this concept to a caninecanine scenario…scenario…

Dog and Cat fertility rates:Dog and Cat fertility rates: Average number of litters a fertile cat can Average number of litters a fertile cat can

produce in one year: 3 produce in one year: 3 • Average number of kittens in a Average number of kittens in a

feline litter: 6 feline litter: 6 • In one year, that makes 18 new kittens.In one year, that makes 18 new kittens.• In four years, one female cat and her In four years, one female cat and her

offspring can theoretically produce 20,000 offspring can theoretically produce 20,000 cats. cats.

Continued…Continued…

Average number of litters a Average number of litters a fertile dog can produce in fertile dog can produce in

one year: 2 one year: 2

• Average number of puppies in a canine Average number of puppies in a canine litter: 8 litter: 8

• In one year, that makes 16 new puppies.In one year, that makes 16 new puppies.• QuestionQuestion: In four years, how many : In four years, how many

puppies can one female dog and her puppies can one female dog and her offspring theoretically produce?offspring theoretically produce?

Let’s see how you did…Let’s see how you did…

DogsDogs

Using a litter size of eight puppies, and Using a litter size of eight puppies, and two litters per year...two litters per year...