As rats age, they may become either obese or thin. If your rat has a health problem, please consult your veterinarian about feeding and nutrition. However, if your rat is aging normally, you may be able to help it live a longer life by supplementing or changing its diet. Rats prone to obesity as they age can benefit from eating more low-calorie foods and being made to exert physical effort to get them, while rats that are losing weight may need supplementation with calorie-dense foods, or possibly even help with eating.
Obese Aging Rats
If your aging rat is gaining an unhealthy amount of weight, first consider if it may have a physical problem preventing it from remaining as active as it once was. Could hind leg degeneration, arthritis, or some other health condition be keeping your rat from moving around? If the vet gives it a clean bill of health, try increasing its exercise by giving it extra free range time in a rat-proofed room, and hiding snacks around the room to encourage foraging activity. Use low-calorie treats like chopped kale and fresh berries. Remember, decrease the amount served of your rat’s staple diet if you give treats. You can also get creative and encourage foraging for the rat’s regular meals– try hanging lab blocks from the roof of the cage!
If you hide or hang all the food in the cage, keep an eye on your rats and be sure that all rats in the cage have figured out how to get food. Most rats learn quickly, but there are a few less creative rats who will not learn to remove hung lab blocks or find kibbles stuffed inside dog toys.
Skinny Aging Rats
Rats often lose weight as they age. This could also be due to a physical problem, such as dental malocclusion or a pituitary tumor. If a veterinarian rules out a health issue, but your rat is still losing weight with age, try adding calorie-dense and easy to eat supplements to a balanced diet made for rats. My staples for aging rats suffering from weight loss are chocolate flavored Ensure (or a grocery-brand generic version like Fortify) and hard-boiled egg. Most rats prefer the yolk, so if you like hard-boiled egg whites, feel free to snack on them and offer just the calorie-rich yolk to your ratties.
If you suspect your rat is having trouble chewing lab blocks, try soaking them in chocolate Ensure in your refrigerator until they are mushy. Be sure to toss the mushy blocks after a couple of hours and offer fresh ones at least twice each day. If you really can’t seem to get your rat to eat on its own at all, try a syringe full of Caro syrup to raise its blood sugar and encourage it to eat until you can get to the vet— anorexia in rats is a serious condition and requires a vet visit.