Is this weight gain normal?

[LilyandDaisy]

My gerbils are 14 months old now and are still gaining weight, especially Daisy. Daisy's up to 91g now. She doesn't look fat, just chunky, but she feels so heavy. Should I be worried about her weight, or is it fine as long as she doesn't look fat? Some sources say gerbils grow up to 6 months, and others say up to a year, but mine are over both those ages now. Below is a graph showing their weights over time, and some recent pictures of Daisy.









As the graph shows, Lily has gained weight too, but I'm less worried about that as she used to be underweight. For some reason at 12 weeks she just stopped gaining weight and actually lost a bit. She has filled out now and looks much healthier. Below are pictures of her at 8 months and at 13 months, showing how much better she looks.





Up to the end of last year (up to week 40 on the graph) they were fed Gerri Gerbil (17% protein, 8% fat). Then I tried Versele Laga but didn't like it, so I mixed it with Gerri Gerbil and fed that up to the end of April (week 60). I mixed equal quantities of both, so it would have had about 16.75% protein, 7.5% fat. Then I started feeding a mix of 4 different commercial foods and this mix works out as having 15% protein and 6% fat. The fat levels don't seem high to me, so I'm not sure that diet is the issue. Or perhaps Daisy just needs less fat than other gerbils?

I am thinking of adjusting the ratios of each commercial food to produce a mix with lower fat, but I'm unsure whether this is safe, and I don't want to make Daisy lose weight if it isn't necessary. I would appreciate any insight or advice.  

[betty]

Hello LilyandDaisy.

Firstly, a weight range of anything between 60g and 90g is pretty much standard for a mature female gerbil, so I wouldn't worry there as long as she looks 'the same shape as a normal gerbil' - ie - not growths or swellings to cause the gain.

Also, changing the balance of foods to lower the fat level doesn't take into account all the other nutrients in those foods that aren't listed in the side of the packet - so I wouldn't be too picky on just that one number - especially as you are combining foods. Increasing exercise through enrichment can help keep the weight where you want it while also not affecting the other nutrients she is eating.

Finally - and this is in two points - I know this may have just been for effect - but offering your gerbils their food in such a big portion could be swaying the bits she eats (unless you don't add more food until the entire lot has gone). Selective feeding is the number one cause of weight gain.

And also feeding this way (large volumes that are often stood on by the gerbils) can contaminate the food (by having stood in their own wee first) and cause some of the nutrients to become lost (by over exposure) or the food to be less appealing (like stale bread). Feeding (very) little and often is the best way for full nutrition to be ingested when the food is at its freshest - and this includes where it is stored before you feed it too. Storing seeds in the window for example (or keeping them in a heated room) can totally ruin the oils and fats that are the reason the seeds are put in the mix in the first place. Just like human food: just because a food still looks the same on the outside - doesn't mean it still contains the same on the inside - all very detailed I know.

But then I am rather a nerd...

[LilyandDaisy]

Thanks for your reply. She does look a completely normal shape for a gerbil when she's under 90g. Above 90g and she starts to feel a bit too squishy and she isn't so agile, so I'll try to keep her at 90g. She gets a good amount of exercise free roaming 2-3 hours a week but she likes to take shortcuts. Instead of climbing onto a piece of furniture she sits and stares at me until I pick her up and lift her. She has a wheel that she uses occasionally outside the tank as it doesn't fit in the tank.

That photo with her in the tin isn't how I usually feed them! I had the tin open while feeding them. and she jumped into it. I let her eat long enough to take the photo and then removed her. I have a scoop which I've worked out holds about 20g of food, so I feed one scoop daily scattered over the bedding along with a small amount of fresh food 3-4 days a week. They tend to gather all the scattered food and hoard it underground rather than eating it on the spot, so I'm not sure how fairly divided between them it is as I don't see them eat. They're generally a quite peaceful pair though and I never see any bullying or squabbling or hear any squeaking.

Would freezing food preserve the nutrients better? As I combine foods and only have the 2 gerbils and 1 hamster I have a lot of extra food. I make up their food in small quantities (2 weeks' worth) at a time because inevitably the smaller seeds fall the bottom. Making it up in smaller quantities ensures that even if their daily ration isn't always completely balanced, their two-weekly ration is, if that makes sense. At the moment I keep it in airtight containers in a dark cupboard.

[betty]

Yes, keeping food chilled or very cold is usually the best plan for long term storage - so many people keep them in a dark place in the kitchen, celler or garage and ideally in a vermin-proof container. No point saving money on bulk buys if it 'goes off' or get contaminated in the time it takes to eat it. Storing you ready-to-eat mix in an airtight container in the dark couldn't be better.

And as for enrichment - it isn't just about the excercise you see - although that certainly helps. For example filling their enclosure losely full of hay or shredded paper will certainly keep them active WAY longer - and when they are naturally active rather than the mad burst when you have them out. Anything else really that means they can set their mind to something (gerbils don't like to give up) so a wooden bridge right in the way of their normal route - they will just HAVE to destroy it.

Is ther anyway you can create more levels in your tank and only put the tasty treats and new things right up the top - so they have to run around more to take advantage - also if you have the space you can always hang the wheel off the top or side of the tank so that they can use it more often?

I am sure you have thought of most of thise things anyway - but just suggesting a few random things here that have worked for other peoples gerbs.

[betty]

Loved you graph by the way - I really need to invest some time in learning how to better display my data.

[LilyandDaisy]

Since my post about Lily and her boredom in the evenings I was able to move some furniture around and make room for a 120cm tank which they're in now, though it still isn't quite enough for Lily's liking but she's not even satisfied with a whole room when she's free roaming. Above the tank there is a long wide shelf and in the evenings when I'm around to watch I take the lid off the tank, put some toys on the shelf and they jump up to the shelf and play. They get most evenings from 6pm until about 10pm to play on the shelf. Now that we're at home so much I often let them onto the shelf as soon as they wake up from their midday sleep, which is about 3-4pm. Unfortunately the shelf means there isn't enough height for a topper and I'm not allowed to remove the shelf. The tank was custom made as tall as possible to fit that spot. As you can see from the picture, there's no height in the tank to fit a wheel or any extra shelves.



I still have the 75x45cm tank they were in before, and it's in a place where I have plenty of height to build a very tall topper. I have sometimes wondered whether they would be better off the smaller tank with a big topper, or in the longer one with more burrowing space but no topper? Obviously both would be ideal, but isn't possible. I'll have to give that some more thought.

I do give them hay and shredded paper quite often, and dried or fresh herbs and leaves to forage for. I have sometimes placed a toy near the entrance of a tunnel where I know it will annoy them enough to focus on destroying it, and have felt a bit bad about annoying them like that but it does keep them occupied.

I started the graph as a kind of project to see how gerbils' weights change over their lifespan. That's why I weigh them weekly, to get more detailed data. One thing that was interesting was how Lily started out heavier until 12 weeks, when they swapped over. There was also a subtle power switch around the same time. Lily used to be slightly more dominant, and now it's Daisy.

[betty]

I love that new tank - look at the burrowing!

And yes, collecting stats is sometimes really interesting and I like a bit of citizen science. By collecting what seems like everyday data (like weight) over a long time by a lot of people can sometimes revela great secrets - things that on their won don't get noticed or seem irrelevant. But you have to build up enough to see things that don't at first seem to be connected (until you find that it happens every June or that 200 other people all noticed the same silly thing.

Anyway - great that you are having fun enriching the tanks for your gerbils - almost like a bit of self-enrichment too!