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So, do rabbits go into heat? What is it with rabbits “breeding like rabbits?” In this post, we will discuss rabbit reproduction and how it affects the care of your pet.

Two important statements before you read further.

FIRST: Know Your Rabbit does not support the breeding of rabbits and is a proponent of the “Adopt don’t shop” campaign to reduce the number of homeless rabbits needing care.

SECOND: Know Your Rabbit is a firm believer that all house rabbits must be spayed or neutered. This post is for educational purposes and is not meant to condone the breeding of rabbits for any reason.

Do rabbits go into heat?

This question is an often-asked one. The answer is sort of murky actually, though the short (ever-so-slightly inaccurate) answer is “No.” Let me explain.

Heat is a term used to describe the time that an animal is most fertile and receptive to mating due to the cycle of ovulation and menstruation. These are animals with menstrual cycles and the cycle varies among species. Humans, dogs, and many other mammals fit into this category; though I strongly advise against asking any woman if she is in heat. It won’t end well.

The Oestrus Cycle

Female rabbits do not menstruate. Rabbits have an “estrus cycle” (sometimes spelled “oestrus”) instead of a menstrual cycle. Rabbits will resorb the endometrium rather than shed it when they are not pregnant.

I did say this was a cycle, which implies that there may be periods when a rabbit is more “ready” to conceive than others. It has to do with follicular development within the ovaries that triggers the release of estrogen, which then causes the female to be “receptive.”

Love is in the air

This happens over two weeks and if pregnancy does not occur, the follicles degenerate and the estrogen levels drop.

For four days! After which the cycle repeats.

Sorry, not sorry.

Now, to add to the confusion, I am going to tell you that there is no defined estrus cycle.

I know what you are thinking. You stink as a writer. (I hope not)

If you re-read the paragraph above about follicular development it says that this is what triggers the release of the estrogen. But, the actual development of the follicles occurs in what Dr. Varga describes as “waves” with “5-10 follicles in each ovary being at the same stage of development at any one time.” (Varga, 82).

So, there is no truly defined cycle, but there is a cyclic rhythm during which female receptivity varies. Semantics, semantics…

Here is what Dr. Molly Varga says in her Textbook of Rabbit Medicine:

“Many factors influence this cyclic rhythm including nutrition, light, temperature, sexual stimulation, and individual variation. In general, the receptive period lasts 14-16 days with a period of non-receptivity for 1-2 days.” Varga, 82

Meh Sometimes she just won’t be interested

What is an induced ovulator?

“Mimosa (Houdini’s Magical Moment)”

Photograph by Mari Etelä / @magical_mimosa on Instagram

When you come across a debate (on social media perhaps) about whether or not rabbits go into heat, you will hear the opposing view that they don’t go into heat because they are “induced ovulators.” This is true.

Even though rabbits have the oestrus cycle just described, they will not release an egg to be fertilized unless “induced” to do so.

If a male mates with a female, ovulation will occur in ten hours. But, other events can induce ovulation too.

Yup. A female rabbit can ovulate in circumstances other than mating with a male. Mechanical stimulation, mounting behaviors by another female, or even just being close to a male can induce ovulation.

Please don’t stand so close to me

So, what happens in those cases?

Pseudo-pregnancy

If ovulation occurs without fertilization, the female can experience a pseudo-pregnancy. And it is very real to the rabbit.

Pseudo-pregnant females will pull hair from their chests and build a nest just as a pregnant female. They will aggressively defend their nest and will even develop mammary glands. This will last for 16-18 days.

At what age are rabbits sexually mature?

Rabbits hit puberty in their first year, as early as four months! Larger breeds may hit a few months later because interestingly, sexual maturity is related to the time a rabbit reaches around 75% of their ultimate bodyweight.

Three more interesting facts

Pregnancy lasts 31-32 days. A female can have up to 6 litters a year and produce 40-50 offspring! Parturition (the act of birthing) takes place in the morning and lasts less than an hour. (finally, some bit of good news for our lady rabbit friends!) It is referred to as “kindling.”

Summary

Well, I think it is fair to say that rabbits do not “go into heat” in the sense that we use that term for other animals, but there are some rhythmic patterns to their receptivity. (as in: on, on, on, on, on, off, on, on, on, on)

Rabbits can be induced to ovulate in a few different ways and may subsequently experience a month-long pregnancy, or a half-month long pseudo-pregnancy.

Because ovulation can be induced by proximity and non-sexual mounting behaviors, pseudo-pregnancy can occur in rabbits that are housed together.

Spay or neuter your pets including your rabbits! You will make the world a better place.

QUIZ: Guess how many rabbits one pair of rabbits can make in four years?

Click here to see the answer on the House Rabbit Society Website. I guarantee you will be amazed. (Clue: they refer to it as the “Bunpocalypse.”)

References

Varga, Molly, BVetMed CertZooMed DZooMed (Mammalian) MRCVS. Textbook of Rabbit Medicine, Second Edition.2014 Elsevier Ltd.

Acknowledgments

A special thank you to the lovely Mimosa and her humans for the photograph. Mimosa is a much-loved house rabbit living with her bunny companion Tahvo and her human “parents”. Mimosa is a 1-year old Holland lop who is enjoying a cage-free life with her family in Helsinki, Finland. Follow her on Instagram @magical_mimosa.

Finally, the brown and white bunny in the photographs above is my bunny, Pudge. (Isn’t he cute?) These photos are meant to light-heartedly represent the biophysiology discussed in this post. NEVER EVER feed your rabbits chocolate!

Thanks for reading. If you liked this article, please share to your favorite social media platform with the buttons below. And don’t forget to leave us a comment. Thank you ❤

Love,

Michele and Pudge ❤