Hermit Crabs & Temperature
By Sara Caruso
Hermit crabs make great pets for both children and adults. Like with any pet, keeping them stress free is key to keeping them healthy. For hermits, a common cause of stress is dramatic changes in temperature or humidity. Too much stress can lead to serious health conditions, so it is important to watch them closely for any signs of deterioration.
Purple Pincers (Coenobita clypeatus) are land crabs found in the Caribbean, with Haiti being the largest supplier for the species. These crabs are hardier and easily adapt to life in our homes and to a wider variety of shells. In the wild, they climb and hide in trees during the day, coming down to feed at night. Their ideal temperatures for survival are between 70 to 76 degrees Fahrenheit with 75-80% humidity. While they can survive slightly higher or lower temperatures for short times, a sudden temperature shift can result in stress and injury.
Often, the first sign of stress is lethargy. While molting can also cause lethargy, with temperature stress other symptoms will begin to surface. A crab that gets too warm will often spit up a dark, slightly metallic smelling bile. Too cold, and the crab will begin dropping its legs. Unlike a molt where only the exoskeleton is shed, in this case the entire limb will fall off. With dedicated care, it is possible for the crab to recover and the limb should regenerate after a molt. Gently dipping the crab into a solution made of one-half gallon of chlorine-free bottled water and 125 mgs aquatic tetracycline will reduce bacteria and can help make the molt easier. If you see signs of temperature induced stress, quickly move the crabs to more stable temperatures. It is very difficult for hermit crabs to recover from this type of stress, so it is better to prevent these easily avoidable situations.A simple way to avoid temperature stress is to make sure your crab enclosure is located away from HVAC vents and windows. Temperatures in these locations can vary greatly from the surrounding room.
A constant temperature shift, such as from an extended power outage, can cause temperature stress to hermit crabs. During a summer outage, as the temperature rises, move your crab enclosure to the floor or to the lower level of your home. Lightly dampen a towel and drape it over the crab’s enclosure to maintain humidity. Frequently misting the towel will help bring the temperature down. Be sure to remove the damp towel once the temperature returns to normal. For a winter outage, as the temperature drops move the enclosure to a higher point such as a shelf, counter, or desk and cover it with a towel or blanket. During a long-term power outage, place the crabs in a zipper-type insulated lunch bag. Make sure the bag is zipped as the crabs will instinctively try to escape. Place the insulated bag with the crabs inside into another zipper-type insulated bag or wrap it in a flannel blanket. Never place living creatures in a plastic bag. Placing your hermit crabs in your in your pocket can also help keep them warm.
It is important to keep hermit crabs out of areas where temperature stress can occur. Routine monitoring and daily interaction with your hermits will help you recognize the early signs and take preventative measures before injury occurs, so your hermit crabs live long and happy lives.