It might increase the humidity some, if it is hot that may not be the best. You can also fill soda bottles with water and freeze them. The bunnies will sometimes flop or lay next to them to keep them cool. If it gets too cold you can put a tube sock over them too. Check out BB’s “Cooling Tips” in the Bunny Info tab at the top.

that’s a neat tip. I think it would work to their cooling benefit because the sheet’s dampness would be cold to start out and then blown around immediately. The dogs’ body temp makes a damp blanket icky fast but there is no circulation involved.

Somehow I posted questioning weather humidity affected buns in the wrong thread.

As for cooling the buns, I find that mine like to lye on cool surfaces such as tiles.

I found this article relating to rabbits and how they handle the humidity. They are not able to remove the extra moisture from their respiratory tract as easily. Higher humidity can reduce the rabbits activity level, less eating, and can result in some weight loss during warmer months. I would assume that if the rabbit is less active then the gut motility is affected as well and could result in blockages. Just a thought!

http://ressources.ciheam.org/om/pdf/c08/95605280.pdf

 I found this as well:

“The effect of humidity”

“Rabbits are sensitive to very low humidity (below 60 percent) but not to very high humidity. This may be explained by the fact that wild rabbits spend much of their lives in underground burrows with a humidity level near saturation point (100 percent) while the humility in Viet Nam especially in Central areas verry high. On winter season, the humility usually 90 percent that is too inconvenient for rabbit’s activities. The rabbit has more to fear from abrupt changes in humidity. Constant humidity is therefore the best solution, and this will depend on the housing design. For Viet Nam rabbit the humidity levels around 75 to 80 percent are successful, so we should using auxiliary heating in winter season. However, the temperature and humility have relarionship and have effected together. When the air temperature is too high and humidity is also high, not much latent heat can be exported as water vapour through evaporation. The result is discomfort which can be followed by prostration. Very hot spells with near 100 percent humidity can cause serious problems. Unfortunately this is common in tropical climates during the rainy season. When the temperature is too low and humidity close to saturation point, water condenses on poorly insulated walls, especially at so-called “heat bridges”.  Water is a good heat conductor and so the cold becomes more penetrating, causing heat loss in the rabbits through convection and conduction. Digestive and respiratory disorders often follow. When the surrounding air is cold, excess humidity modifies the secretion and viscosity of the mucus protecting the upper respiratory apparatus and when air is too dry (relative humidity is below 60 percent) and too hot is even more dangerous. Not only does it upset the secretion of mucus but also the ensuing evaporation shrinks the size of the droplets carrying infection agents, enabling them to penetrate more easily the respiratory apparatus. “

Using a fan and wet sheet is a form of evaporative cooling of the air. That type of cooling is less effective in humid conditions. The moisture content in the air is alread so high. Cool surfaces to for rabbits to lie against would help better.

I would not think you would ever want to put a wet sheet over a fan for safety reasons. Also a dry heat is not going to be as uncomfortable as a humid heat. It’s still going to be hot but you want to keep the humidity factors low not increase them.