Spaying and Neutering your rats can be a beneficial operation, particularly in the case of spay surgeries performed on young female rats. Many male rats will also benefit from the less invasive procedure of neutering. However, there is no black and white answer on if you should have your rats sterilized; What may be useful for one rat may not be the right choice for another.

The decision to spay or neuter your rats should be made based off of their behavior and the potential health benefits. If you plan to keep males and female rats together, it is critical that at least all of one gender of the rats in that colony be sterilized to prevent uncontrolled breeding. If you are planning to keep your rats in same-gender groups, the surgery may be more selective.

We hope that the information provided here will help you make a more informed decision in the best interest of your rat(s).

General Notes for Rats in Surgery

It is very important to take your rats to an experienced exotics veterinarian for a spay or neuter surgery and not to a veterinarian who only sees cats, dogs or other species of animals. A Veterinarian who is experienced with rats will significantly decrease the risk of surgery. Special attention should also be paid to keeping the rat warm during and following surgery. Many Veterinarians who perform this procedure will also administer antibiotics to prevent infections following the surgery. In some cases, it may be necessary for pain medication also to be prescribed if you have a rat who is very sore following the surgery. Most rats who are spayed and neutered can go home the same day following surgery.

We do not recommend using metal sutures or staples for rats if it can be avoided. Many veterinarians will use stitches that will dissolve in the weeks following the surgery, eliminating the need for a follow-up visit to remove sutures or staples. Staples, in particular, can be very uncomfortable for rats, and rats may rip them out and need to be taken back for an emergency visit to close the site of the incision.

Female Rat Spays РProcedure and Benefit

A female rat is generally spayed by a procedure called an Ovariohysterectomy, which is the removal of both ovaries and the uterus, or an Ovariectomy, where only the ovaries are removed. An Ovariectomy also has health benefits but will not prevent uterine cancer and other uterine complications that will be prevented by an Ovariohysterectomy.

Female rats who are spayed have a reduced chance of developing estrogen-fueled tumors and are less likely to develop mammary and pituitary tumors. One study (Hotchkis, 1995) found that in unspayed rats used in the study, 49% developed benign mammary tumors, 8.2% developed mammary carcinomas and 66% developed pituitary tumors. In the spayed rats used in this study, 4% developed mammary tumors; none developed mammary carcinomas and 4% developed pituitary tumors. Given the inoperable nature of pituitary tumors, this is a massive health benefit for female rats.

Female rats who have an Ovariohysterectomy are no longer at risk for developing uterine cancer, as the uterus has been removed. It also eliminates the risk of Pyometra, a hormone-mediated disorder where the uterus becomes abscessed and pus-filled.

Unspayed female rats go into heat every four days, and during this time they can be excitable, frantic, grumpy or have other changes in their personality. Some owners also report a reduction in ammonia smell in their rat’s urine, although we currently are not aware of any studies on this possible additional benefit.

It is an ideal time for female rats to be spayed between 3-6 months as the effects of estrogen are cumulative, and may be already present in an older rat. However, spaying an older rat may still be beneficial by halting estrogen production and decreasing the rat’s likelihood of developing mammary or pituitary tumors later in life.

Female rats are sterile immediately following an Ovariohysterectomy.

Male Rat Neuters – Procedure and Benefits

A male rat is neutered by the surgical removal of the testicles, also called castration. Rats have an open inguinal canal, which is a passage in the anterior (toward the front of the body) abdominal wall which conveys the spermatic cord, so this surgery should be done using a ‘closed method’ to prevent bacteria from traveling between the scrotum and the abdomen. This procedure greatly reduces the production of testosterone.

Male rats who are neutered are less likely to display aggressive behavior towards other rats and are less likely to initiate a conflict. Studies have shown that male rats who have been neutered display up to 85% less aggressive behavior then prior to their neuter surgery. Neutered male rats are also half as likely to be attacked by intact male rats.

Neutering can either significantly reduce or completely eliminate scent marking behavior. Many male rats will leave small drops of urine as they walk, although neutered rats have been shown to decrease this behavior by an average of 80%. Many pet owners report that male rats who have been neutered completely stop scent marking.

Neutering male rats also decrease the metabolic rate, which can cause a slight increase in the chance of obesity but may also delay death in the event of a terminal illness. A reduced amount of testosterone also shows a slight decrease in the likelihood of male rats developing testosterone induced tumors and eliminates the risk of testicular tumors.
Neutering also tends to make a male rat’s coat smoother and less coarse. Male rats are sterile three weeks following a neuter surgery.

Preparing for Surgery

Rats who are sent in for a spay or neuter surgery should ideally be in good health without any active respiratory problems, which can increase the chance of complications during surgery. Other health problems should be addressed or controlled prior to sending your rat in for surgery. It is not necessary for rats to fast prior to a spay or neuter surgery, as rats cannot vomit there are not the same risks cats and dogs face of aspiration if they do not fast.


After the surgery, your veterinarian may prescribe antibiotics or may have administered an antibiotic shot. This is an important precaution in preventing infection at the surgery site. Most rats will come home the same day from their surgery, and this is preferable so that you can monitor their condition following the surgery. It is not uncommon for rats to be more lethargic following the surgery, but they should be eating, drinking, and moving around without showing signs of significant discomfort.

Particular attention should be paid to your rat’s comfort after the surgery. If your rat seems to be in pain, talk to your veterinarian about prescribing pain medication to help your rat during this time. Most rats recover quickly from this procedure and will be back to their old selves in one or two days following the surgery. Keep the handling of your rats to a minimum to avoid stress being put on your rat’s stitches.

If your rat has a buddy, you can place them together after your rat has woken up and recovered from the anesthesia. Monitor the rats to ensure that none of them are bothering the site of the incision. Housing your rats on plain paper towels can help you monitor for signs of bleeding following the surgery, and bedding should be changed regularly to keep things sanitary while your rat is healing. If you have a cage that is largely vertical, you may want to consider moving your rat into a flat cage temporarily while they are healing if they show signs of discomfort from climbing in the cage.

Risks and Possible Complications

Any surgery carries a risk of complications, and this should be evaluated before sending your rat in for a spay or neuter surgery. This risk is significantly reduced by having rats that are in good health spayed and neutered by a veterinarian who is experienced with the procedure. Rats may react poorly to anesthesia and may have problems waking up after the surgery. Some rats may have bleeding complications during surgery, which may pose an immediate danger and/or prolong recovery time. Following the surgery, some rats may pull open their incision or bother the wound. Secondary infections can occur both at the site of the wound and internally.

Conclusion: Should rats be spayed and neutered?

While there are exceptions to each rule, and each rat should be evaluated on a case by case basis, we believe this is a beneficial surgery that should be performed when there is an availability as the benefits largely outweigh the risks. In female rats, a spay surgery may eliminate the risk of your rat developing mammary tumors later in life which would need a surgery visit anyway. Many female rats have multiple mammary tumors, so there is a chance that a one-time surgery will significantly reduce or eliminate your rat developing mammary tumors. It also significantly reduces the chance of pituitary tumors, which are inoperable and eventually fatal.

We do believe that neutering male rats is elective, but as this surgery carries less risk than a spay surgery on a female rat, it can still be very beneficial. We do not believe that anyone should neuter male rats for aesthetic purposes, but the benefits of reduced aggression, scent marking, and eliminating the risk of testicular cancer can be of great benefit.


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