If you have the privilege of owning both a dog and a cat, you may be wondering if there is a risk of them breeding together. But what would be the result? Is this even possible?

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In short, no.

Whilst it may be amusing, imagining a dog-like cat or a cat-like dog, they are too different from one another to produce offspring. 

Whilst we group dogs and cats together as they are the most domesticated pets in the modern world, serving a similar kind of companionship for human civilisation, they are completely different animals. Their last common ancestor was approximately 42 million years ago. 

42 million years is a long time. Dinosaurs went extinct about 65 million years ago. Modern humans only evolved 130,000 years ago. Modern civilisation developed 4000-5000 years ago. The Roman Empire ruled the world 2000 years ago. It is hard for our comparatively measly little minds – that recognise time in decades – to comprehend just what 42 million years looks like. It’s just too big a number.  

There’s still so much we have left to learn about life on this planet. We don’t yet even know what we don’t know. But we do know one thing is for certain: dogs and cats cannot create a hybrid species. Read on to find out why. 

They are genetically incompatible

Firstly, they have a different number of chromosomes. Chromosomes are molecules of DNA — our genetic code — that pass down genetic information from parent to offspring. Cats have 19 pairs of chromosomes. Dogs have 39. It is not so much the numbers that determine a species’ uniqueness, but the content that makes up the chromosomes. But having the same number of chromosomes is helpful for the creation of offspring. Dogs and cats have a difference of 20 in number, a huge gap that would make breeding impossible. 

The more similar the DNA is, the more likely a creation of a hybrid species becomes. 

They don’t recognise mating signals 

They also have entirely different mating behaviour and have no recognition of one another’s mating signals. Your dog will not recognise that your cat is in heat, and any display of ‘sexual behaviour’ is due to excitement. Dogs tend to have a ‘season’ where they are receptive to males every six months, whereas cats tend to have two to three heat cycles during breeding season. This is when the female cat (queen) will be receptive to males. However, what you may or may not find interesting, is that a queen will only ovulate when mating occurs. This means that the very act of breeding is required for a cat to release an egg from the ovary, and they may need multiple sessions for this to occur. 

The anatomy is completely different

If we’re getting into even more detail here, the anatomy of the ‘appendages’ is completely different. The cat’s penis is barbed. It is thought that these barbs are what stimulates the queen’s reproductive tract. Nature is a marvellous feat of ordered chaos. Did you know that human penises once had spines? It is thought, perhaps, that it was monogamy that led to the loss of penile spines in humans. Fertilisation is no longer (arguably) a competitive sport, whereas for cats, there’s a little bit more pressure for males to successfully succeed in passing genetic material to the next generation of kittens. Barbed penises are thought to be what stimulates the release of the egg from the ovary, thereby allowing fertilisation to occur. 

Therefore, dogs would not be able to inseminate cats, as they do not have barbed penises. Their anatomical structure simply does not allow it – and vice versa, the lack of a bulbis glandis would prevent a copulatory lock, again reducing fertilisation chances.

To conclude, it is in nature’s best interest to prevent species from cross-mating

Having a diverse number of plants and animals across the planet offers a greater chance of life thriving. And at the end of it all, even though humans have the tendency to grapple with the concept of the meaning of life and the point of our existence, the biological purpose of life is simply to survive. Dogs and cats are simply too genetically different for them to succeed in making offspring. 

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