Can Cats and Dogs Mate?

Last Updated on September 28, 2021 by Julia Wilson

Can cats and dogs mate?

It’s not out of the question that a cat and dog can engage in the act of mating (copulation), but it is extremely unlikely. Both animals would have to be receptive, which is almost never going to happen. Sometimes a dog may mount a cat as a sign of dominance, they don’t physically engage in copulation as there is no penetration.

Can cats and dogs produce hybrid offspring?

Even in the unlikely event that a cat and dog mated, they would not be able to produce offspring. Some members of the cat family can mate (for example, lions and tigers) and produce offspring, but a lion and a giraffe or a dog and cat cannot. This is known as reproductive isolation. Reproductive isolation is a collection of evolutionary mechanisms such as behaviours and physiological processes that are critical for reproduction within the same species.

The biological properties of organisms that prevent interbreeding are called reproductive isolating mechanisms (RIMs) and fall into two categories, prezygotic which takes place before fertilisation and postzygotic which takes place after fertilisation.

Prezygotic RIMs

Prezygotic RIMs prevent the fertilisation of eggs in several ways to prevent inter-species crossbreeds.

  • Habitat isolation: Where habitat separates species that prevent mating. While this doesn’t necessarily apply to domestic cats and dogs who live in the same home or neighbourhood, it is a factor that works against cross-species mating. Lions and tigers can produce hybrids, but tigers live in forests and lions on grasslands.
  • Temporal isolation: Different species have different mating seasons. Dogs are dioestrous and only come on heat twice per year, while cats are polyestrous and can come into season (estrus) several times a year. The female (cat or dog) would have to be in estrus and receptive to breed. It is unlikely a female dog or cat would be receptive to mating with a member of a different species.
  • Mechanical isolation: The male and female genitalia would have to match in order to successfully mate. Even if both cat and dog are a similar size, the cat’s penis is considerably smaller than that of a dog of equal size and would be unable to penetrate the dog’s vagina successfully. The male cat penis also has spines, which rake the walls of the vagina which serve as a trigger for ovulation. Male dogs don’t have spines on their penis to trigger ovulation.
  • Behavioural isolation: Each species has its own courtship behaviours  (mating songs and dances in birds, scents, lordosis in cats, human flirting etc), behavioural isolation is the lack of sexual attraction between two species.
  • Gamete isolation: Even if the gametes (sperm and egg) meet, but fertilisation is impossible as the sperm doesn’t have the receptor proteins or enzymes to break through the egg wall.

Postzygotic RIMs

Supposing the cat and dog were able to successfully mate, there are checks in place to further prevent hybrid offspring.

  • Hybrid inviability: Even when an egg is fertilised by the sperm of another species, the zygote (a single cell that contains the genetic code from both parents) will fail to develop normally in the womb, and does not survive beyond the embryonic stages.
  • Hybrid sterility: It serves as an evolutionary benefit that cross-species mating cannot occur. Most hybrid animals are sterile due to hybrid incompatibility, which is thought to be the result of alleles at different genetic loci that do not function well together. All life wants to pass its DNA on to the next generation, and cross-species mating is a dead end. Mules are a cross between a horse and a donkey but are always sterile due to an uneven chromosome count. Each organism has pairs of chromosomes they inherit one of each chromosome from the mother and one of each chromosome from the father (humans have 23 pairs, cats have 19 pairs and dogs have 39 pairs.
  • Hybrid breakdown: A type of reproductive failure that appears after the second generation (F2).

What is a puppycat?

Cat lovers may have heard the term ‘puppycat‘, this refers to a type of cat with dog-like qualities.

Frequently asked questions

Can cats and dogs sleep together?

Cats and dogs who share a home will often cuddle up together while they sleep, some will even groom each other, but they will almost never mate.

How to stop dogs or cats from mounting other animals?

Mounting behaviour is extremely common. One of our male cats mounts our female cat. Both animals are desexed, and he does it as a form of dominance. Interestingly, he hasn’t tried to mount the two other male cats in the house, just the female.

If you do have a dog or cat who is mounting other animals, desexing should greatly reduce the incidence, although some animals will continue to do so on occasion as an act of dominance.

Can cats who are siblings mate?

Yes, cats will mate with siblings and parents. This is why it is important to desex all cats before they reach sexual maturity at 6 months.