Sexy Bunnies

Tiny little bunches of fur with eyes closed, ears folded tightly against their head. If you pull their lips back, ever so gently, you can see the most perfectly formed beautiful little teeth. Usually 6 to 12 bunnies are in a litter and they will fit inside a very small basket. They start hopping out of their nest area shortly after their eyes open around 10-14 days of age. They stumble, they try to wash their face like the big bunnies, but tumble over while learning what balance is all about. They start eating hay and veggies. Then they start trying to dance! Baby rabbits are the cutest most adorable little creatures in the whole world-for about 10-12 weeks! And then all hell breaks loose.

Baby bunnies often start using the litterbox around 6 weeks of age. I hear people say proudly, that their newly acquired 8-week-old bunny is already litterbox trained. People are so happy with their new rabbit during this time. And then puberty hits! And the good times of litterbox usage is gone-at least until the little darling is spayed or neutered.

In the male rabbit, testicles descend as early as 10-12 weeks of age, which puts them into the “teenage” phase of a rabbit’s life. They may be a bit too young to impregnate a female bunny (although don’t count on it), but they begin to exhibit all of the bunny sexual behaviors. Behaviors may include, dropping their fecal pellets all over your house to mark their territory and urinating outside of the litterbox. They may spray and mount you or a stuffed toy and will begin mounting other rabbits whether male or female. These teenage rabbits will circle your feet (round and round) and can trip you if you’re not careful. You can often hear a humming sound while they circle you. Females may exhibit all of these same behaviors beginning about 1 month later.*

This very messy period of a rabbit’s life is when new rabbit caretakers start searching frantically for information about their companion. If information is located about spay/neuter they will realize that this period will pass once their rabbit is altered and there can be a happy ending. If the caretaker doesn’t locate the information or decides that surgery is too expensive, the story will likely not end well. (Our veterinarians will neuter a male as soon as his testicles descend, about 3 months of age, and a female at 4 months.) So now you’ve survived the messy period, and your rabbit is altered. Most rabbits will turn into very polite rabbits following their surgery. Their urine and feces are deposited into the litterbox. The spraying stops. Bunnies remain very active, adorable and their energetic selves, and everyone lives happily ever after. At least that’s what you’ve been told, and in the vast majority of cases it is true.

However, it isn’t happening to your rabbit. So you check and find that his hormones should diminish in 2-4 weeks, so you wait and wait and wait. But he continues to act as though he’s not altered. Marshall is such a bunny. He is Mr. Personality. He’ll rip a page out of the phone book and run around the house with the page in his mouth while it covers his eyes. Why he doesn’t run into things is beyond me. He is so filled with joy, does super bunny dances, and would make someone a great house rabbit, if only he would stop spraying and spreading his feces everywhere.

Marshall had an ultrasound to find testicle remnants, a third testicle, a tumor, or some reason for his behavior. Nothing was found. Next, our veterinarian wondered if Marshall’s hormones were within the normal range for a neutered rabbit, but there was no lab that had normal hormone values for rabbits. The University of Tennessee runs hormone levels for ferrets and they had an interest in providing a similar test for rabbits. We gathered up 30 spayed/neutered rabbits, took a small amount of blood from each and sent the serum to the U of Tenn. They were then able to establish normal hormone levels for altered rabbits** and allowed us to learn that Marshall’s testosterone levels were above normal for altered rabbits, which explained his sexual behavior. But still the question was why and what to do about it.

The adrenal gland produces hormones, including sex hormones. Our shelter also rescues ferrets and have several ferrets on monthly Lupron injections, a drug which has been successful in controlling the hormonal effects of adrenal tumors in ferrets. So, we decided to try Lupron for Marshall. A month later, we retested his hormone levels to find they had moved into the nearly normal range for altered rabbits! We will not know for (hopefully) many years if Marshall has adrenal disease, but if Lupron continues to control Marshall’s sexual behaviors, he’ll be able to live the rest of his life as a happy house rabbit.

Sandi Ackerman in Consultation with Barbara Deeb, DVM

*Two recent veterinary books (1, 2) state that female rabbits reach maturity earlier than males. Their use of the word “maturity” seems to indicate reproductive maturity. Over the past 15 years of rabbit rescue, I’ve found it consistent that male rabbits exhibit sexual behavior about one month prior to females, and it’s this sexual behavior that’s being discussed.

**Serum samples can be submitted to University of Tennessee, Clinic Endocrinology Service, Knoxville, TN 37996


1. Textbook of Rabbit Medicine, Frances Harcourt-Brown, Chapter 1, p. 2-3, Chapter 3, p. 71.

2. Ferrets, Rabbits, and Rodents 2nd edition, Quesenberry & Carpenter, Chapter 13, author T. Donnelly, p. 104-144.

House Rabbit Journal Summer 2004: Volume IV, Number 10