My gerbil is acting sluggish, wants to sleep a lot and may also feel very cold and very light.

*This is the classic dehydration symptom set. Dehydration is usually a secondary symptom to something else and for whatever reason the gerbil stops eating and drinking. This can kill in 8-72 hours. It can be very difficult to detect, until the very last stage. Nature has favored a sick gerbil hiding the fact they're ill as sick animals are the ones the predators go after.

*There are three stages to dehydration, they last from 2-24 hours each, usually around 8 -24 hours each.

Stage 1-Animal has curtailed or stopped drinking and probably eating. It will 'sleep in' but eventually rouse when you're there messing with the cage and offering treats and act fairly normally. It will eat a favorite treat, usually. It might be very slightly slow, and where it was hyperactive it might be mellow, but be acting fairly normally for a gerbil.

Stage 2-Animal is dehydrating. It may feel cool to the touch when you handle it, and a little on the light side. It may have stayed in bed, sticking a head up but not coming out, or coming out and fairly promptly returning to the nest. It'll take a treat off but probably not eat it.

Stage 3-Animal is curled up, usually rump up, stomach down, and nose out like it was going to go sliding. It is light, cold, icy cold, and could be that you can't tell it's breathing (!). It won't be as stiff as a dead animal but that can be a rather subtle thing to detect.

You can miss stage 1 and 2 entirely, done evening bedcheck and everything looked ok, then get up at 2 am and look in and find a problem, totally unresponsive stage 3 gerbil...

*Begin rehydration therapy immediately, start at every ten minutes. In between times use a lamp to keep the animal warm, you want to get the blood flowing again, fluid into the animal to rehydrate it, and warm it up. The cornsyrup is a quick energy burst way to get the animal to improve. You may have to do rehydration therapy at 10 minute intervals in excess of 12 hours (! I have and pulled the animal through). It may take hours to get a twitch, an automatic swallow, or a slight heave of the chest you can see. IF however you feel a slight shudder then the animal gets rapidly stiffer around the paws, and it pees a few drops of urine, then it has passed. Animals that have appeared dead except they were lacking the degree of stiffness a dead animal will have by flexing a leg and paw...have taken hours to respond, hours more to pull through, and recovered.

You can test for dehydration by pinching the skin over the shoulders. If it springs back slowly or does not spring back, then the animal is dehydrated.

You can take an animal to the vet if you discover this, but it will be costly and they may not pull the animal through. They can do subcutaneous rehydration, which is injecting fluid under the skin of the animal. In a gerbil this is painful to the animal.

You may get an animal to start coming around, then diahrrea (one of the other symptoms and a contributing factor to the dehydration) will return. You have to fight the battle then of staying ahead of the diahrrea and getting it to stop.

My gerbil feels heavy, not a concave stomach, and the pinch works, but it's still sluggish.

It may have had a minor stroke or a little head trauma (playing flying wallendagerbil and fell off something in the tank and hurt itself) while you weren't there. Make sure it is eating and drinking enough.

My gerbil is sluggish and sleepy, part II

You may have a carbon monoxide problem! Open a window, or remove the gerbils from (usually) a lower part of the house to an upper, and see if they improve. If not then there is something else going on. Gerbils often go down before humans can detect the problem of a carbon monoxide leak from furnace or gas heater, or what have you.

Vacate the place (you any other humans and the animals) and call someone to come check for carbon monoxide leak. IF you are having flu like symptoms or feel sleepy, GET YOURSELF OUT and call someone, do NOT return for the animals.

My gerbil is sluggish and sleepy, part III

Someone sprayed something in the room, that affected the gerbil. Removing them to fresh air or another room may improve them.

My gerbil is sluggish and sleepy, part IV

Allergy reaction to food, bedding, or (one reported case) silicone sealant in a tank. Try the two week allergen quarrantine, and if the symptoms don't abate within hours or no recognizeable improvement in 24 hours, then try housing the gerbils in something other than an aquarium (like a jumbo kritter keeper) on hypoallergetic bedding and see if that does it.