Rat losing weight.

Question
Hi Sandra, my name is Katie and I have had the joy of my pet rat, Basil, for a little over a year now. He was relatively full grown when he came to me (he put on quite a lot of weight soon after) and has since thrived. I always referred to him as fat, but he was receiving constant exercise and upon cuddles, he was still quite bony etc. Over the past 3 or 4 weeks, I have noticed a rapid weight loss on him. He is still recieving the same amount and types of food, and is his usual self - constantly eating. I have also noticed his eyesight isn't what is used to be; he doesn't seem to grab his food automatically when I hand feed him, and sometimes misses. I was wondering if you could give me any informatio regarding what might be causing his weight loss, and if there is any thing I can do for him. I can only guess his age to be 18months to 2 years, and his stools are firm and normal.

Answer
Hi Katie

Basil sounds like he was given a second chance by coming to live with you last year. Is he your first rat?

If so, I am sure your amazed at the intelligence rats display and also the bonding they have with their keeper and the amount of affection they show to their keeper as well.  Males are actually more cuddly than females!! Rats are also very social animals and need the companionship of another rat of the same sex but some rats do well solo, although its usually not recommended. No matter what, it sounds as if Basil did great with the adjustment moving from one home to another.

Weight loss without anorexia is usually a tough call when there are no other signs of illness. Rats are notorious for hiding illness, which goes way back to their wild ancestors who hide illness since its a sign of weakness.

Thats where WE come in!  You have already done your part in it by taking note that he has lost weight, but he also doesn't display any other signs of illness such as lack of appetite,lethargy, sneezing or congestion, porphyrin discharge from their eyes and nose (often mistaken for blood, but rest assure, its not blood!)no lumps or bumps or any of the common signs of illness you would expect to notice when a pet is sick.
It makes it very difficult when they cant talk, doesn't it!?
Here are a few things I want to ask you first off before I can draw any conclusions that are concrete without a hands on exam. This is my so called "virtual exam" and your hands are mine, your eyes will be my eyes too.
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First off, lets look into his mouth and look to check his teeth. You should not notice a foul odor that is indicative of an infection or abscess in the mouth and of course there should be no open sores etc...
There should be no visible overgrowth or uneven growth of his teeth.
 They should all be aligned and not crooked or split.  There is a condition called malocclusion that is the malposition of the teeth that prevents the alignment of the teeth or jaw thus in turn causes serious problems and a Vet needs to be seen for this condition. The rat will need his teeth clipped back for starters if this is the case. Malocclusion can cause the rat to stop eating or not eat well and thus in turn causes weight loss. However, you did say he was eating just fine so I would bet he is not having a problem with his teeth.

Here are a few questions I need answered since I am doing a "virtual exam" rather than a real life hands on physical!

1. What color are your rats eyes and what color is his fur?

2. Does he or has he in the past displayed what is called "head sway"?  If he has you will know what I mean right off: Head swaying is when the rat sits still and starts to sway his head back and forth real fast.  This is a way of rats to focus when they cannot focus on an image that may be too far away.

3. What is his diet on a daily basis?

4. Has he been sick in the past and if so, what ailments did he have, including the date, symptoms, treatment (medications used etc...

5. Does he urinate ok, with no increased urination or decrease?

6. Water consumption: Some rats suck water down like there is no tomorrow, others just take dainty sips and nurse it all week long. By now you should know your rats water habits and if he is part rat, part fish and LOVES water, or just drinks it because he needs to survive.  Have you noticed a change all of a sudden that now maybe he is drinking it like he was stuck in the Sahara desert?  

7.  Next, flip him on his back , taking two fingers, slowly and gently press into his belly going up and down and straight across  . Note if he protests with a series of deep squeaks.  Most rats have a higher pitched squeak that they use when playing or if you nip them in the leg when you close the cage door on them etc....but a real squeak that indicates a serious problem is a deeper sounding squeak that is a series of squeaks in a row and often the rat will take off in fear, as if to escape from the painful situation he was in. If you notice this while palpating his tummy , take note. Also you should not feel any mass under your fingers and I said press gently so you should not feel any internal organs. All you should feel is something foreign above the organs. Hopefully this wont occur.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                8. Let me get back to his vision again for a second. The reason I asked about his eye and fur color will tell me what type of pigments your rat has. All rats have bad vision and in fact if were human, they probably would be considered legally blind in the human world and not even be allowed to drive an automobile, maybe even use a walking stick. Yes its THAT bad!! Red and pink eyed rats usually have vision that is even worse that the dark eyed rat as as they age, cataracts can also develop. Do you notice a haze over his eyes at all?  You can easily test his vision yourself too. Give him a treat that will occupy him and simply hold a pencil or something thin next to him to see if he would turn toward it in a hurry to see what it is, if he sees it or not. Come at him from behind during this test so he doesn't see you from the front. Next, do the same from the front of him, about a foot away, and move it closer to him until he takes notice and starts to sniff it to see what it is your doing!!  Chances are his vision is just getting old as he ages.
Internal parasites can cause acute weight loss too, but also you would see water stools and constant itching himself in the anal area, and you made no mention of that.

Sorry to ask so many questions but answering them will give me a better idea as to what is wrong, if anything. I have a feeling that it is simply due to old age. Often, hormone levels in both male and females play an active role in a rats health causing problems along the way, especially mammary tumors in females (males are not exempt from mammary tumors mind you, they can get them as well but it is not as common)
When testosterone levels elevate you end up with a bold, sometimes aggressive rat. As the buck ages and testosterone levels drop, thinning fur may occur as well as being a little more tired than normal and even weight loss may occur.
If there are no changes that you can see, I wouldn't worry too much but there is nothing wrong with seeking a professional opinion by a qualified vet experienced with rats just for peace of mind.  

Again, if you want to do a follow up and answer the questions I asked earlier, I can get a better picture of what may or may not be going on.

Regards


Sandra