How to Care for a Pet Black Widow Spider
This highly-venomous spider should be kept by responsible, experienced adults only! Do so at your own risk.
Widow spiders are fascinating, often misunderstood animals. As long as you’re careful and don’t take unnecessary risks, black widows are one of the easiest pets anyone could ever care for! They can go for weeks without being fed and require almost no cage maintenance.
Some Cool Bonus Facts: A black widow's silk is as strong and durable as Kevlar (the material used to construct bullet-proof vests)1, they can successfully catch and eat prey several times larger than themselves, and there are actually 31 different species world-wide2.
Yes, Spiders Are Animals
Before going into the logistics of properly caring for a pet black widow, it's important to point out that spiders are indeed animals. During my time volunteering as a keeper at a zoo specializing in invertebrates, I was surprised again and again by the number of people who did not consider bugs, spiders, and other similar critters as animals. Trust me, they are!
In the world of science, every living thing on our planet is classified into a hierarchy of groups. The process and organization of it all is called taxonomy, and the highest-level groups of the hierarchy are called kingdoms. There are six kingdoms: plants, animals, fungi, protists, eubacteria, and archaebacteria. Spiders and bugs definitely aren't plants, and neither are they mushrooms, algae, or one-celled organisms. Therefore, they're animals!
The care required by a widow spider will vary slightly depending on the species. In the United States, there are five:
- Western black widow, Latrodectus hesperus
- Southern black widow, Latrodectus mactans
- Northern black widow, Latrodectus variolus
- Brown widow, Latrodectus geometricus
- Red widow, Latrodectus bishopi
A sixth, very colorful species (Latrodectus tredecimguttatus) is also popular in the spider-keeping hobby. Being native to the Mediterranean region, it is difficult to obtain in the United States, though there are several breeders.
All widow species vary in size and spot patterns. However, each one has the hourglass shape on the underside of the abdomen.
In the wild, once a widow finds a good spot for its web, it generally stays there. This means a widow doesn't need much space in captivity. In fact, its long front legs makes walking or climbing across any surface quite a clumsy ordeal, so a widow is quite happy in a smaller container as long as there is room for it to build a functional web.
These critters do not like being close to the ground and they will attempt to build their web as high up as possible. Keep this in mind when choosing a container! It may seem strange at first, but sometimes the best cage is turned upside-down with the lid on the bottom. With this sort of setup you’ll be able to open the cage without the disturbing the spider and its web.
Aquariums, terrariums, jars, and small display cases all make great enclosures. Whatever you choose to use, make sure there is plenty of ventilation. Stagnant air and the mold that results from it may kill the spider! Additionally, widows are unable to climb glass and plastic so climbable cage decor must be provided. Good things to use are sticks, fake silk or live plants, rocks, pieces of egg cartons, paper towel, etc.
When decorating the enclosure, take care to remember: this is a highly venomous species and you should always be able to see the spider and know its location before opening the cage. Don’t use too much cage decor or the spider will be able to hide too well!
Temperature and Lighting
Most species do fine when kept at room temperature. However, some of the more tropical species, such as the red widow (L. bishopi), should be kept warmer at about 75-80 degrees.
As for lighting, normal ambient room lighting is fine. These spiders are nocturnal and generally active at night. However, don't keep them in a room which is kept dark all the time as they still require a somewhat natural day/night cycle.
Prey can be hard to come by when all you do is sit in the same spot and wait for food to walk or fly by. The world is a big place, so it’s a very lucky day when a yummy bug finally happens to end up in widow’s web. As sit-and-wait predators, these spiders are adapted to eating less often and can go for weeks at a time without a single meal.
- In captivity, an adult widow only needs to be fed every couple weeks or even once a month, depending on the size of the prey offered. Overfeeding can actually be a problem...A widow will not pass up the chance to eat when given food, even when it’s too full, and an overfed spider has a higher risk of having its abdomen burst open during a fall or other accident. A properly-fed widow will have a round abdomen that isn't shriveled.
- Food items you can offer: cricket, grasshopper, moth, mealworm, fly, or cockroach. A single cricket can be purchased from pet stores like Petco or Petsmart for 10-15 cents. If you choose to, you can catch wild insects to feed your spider but beware the potential costs of wild-caught food! Insects you find and catch outdoors may be infected with parasites and diseases which may kill your spider. Bugs caught outdoors may also have eaten pesticide or insecticide-covered plants, or they could be full of contaminants/pollutants if you collect them from roadsides.
- Widows are capable of killing and eating prey much bigger than themselves. However, there is still risk of injury, so make sure to observe and supervise your spider whenever you try a new type of prey item. They're also great hunters, so don't be worried if you accidentally miss the web when you toss the prey into the enclosure. These spiders are very sensitive to the vibrations a nearby insect makes, and your widow will creep up close to the prey, grab the food with its long front legs, and will hoist it up into the web. It's an amazing thing to watch!
Water: A widow gets most of the water it needs from its diet, but it’s still a good idea to provide some moisture by misting one side of the cage or web with a spray bottle once a week or every other week. I personally have seen my black widow drink from a small water droplet. Take care and avoid spraying water directly on the spider! The more tropical species, such as the red widow (L. bishopi), require higher humidity and may need to be misted more often.
Always remember: black widows are highly venomous spiders!
- Never handle a black widow. Make sure children and pets do not have access to the cage and ensure the enclosure cannot be knocked over or accidentally opened. Consider putting small warning label on or nearby the cage to alert visitors about a potentially dangerous animal being in the cage.
- Always know the location of the spider before opening the cage. Widows don’t move much, but keep an eye on it at all times while the cage is open. It’s also a good idea to always have a small “catch container” or “catch cup” sitting within your reach anytime you open the cage. You can grab it quickly and use it to catch your spider if it happens to escape the enclosure.
- Use long tools that allow you to safely work around a black widow. Use long tongs to remove or place objects from or into the cage. Use a long stick (such as a kabob stick) and gently touch the back legs of your widow to make it move if you ever find it necessary to move the spider. Use a small cup with a lid to scoop your spider into if you need to temporarily remove it from the cage.
Cleaning: A widow’s cage hardly needs to be cleaned at all. The only thing you’ll need to do is periodically remove old food if it becomes moldy.
Unexpected Babies! At some point your female widow may create an egg sac. Sometimes these are duds and the eggs are not fertilized. But if your widow is wild-caught, it's almost a guarantee the sac will produce hundreds of little spiderlings. If you'd like to raise tons of itty bitty baby widows, you can do so. It has definitely been done! But if you don't, here are your options:
- You can sell the babies to fellow hobbyists. I've come across many spider-keepers who were willing to take or even purchase egg sacs or large lots of babies.
- You can freeze the spiderlings (the most humane way to kill them) and then dispose of them. This ensures that no non-native, invasive species will get out into your local ecosystem.
1: Silk strong as Kevlar. Science Magazine.
2: Thirty one species of widow spider. Tree of Life Web Project.
Species Photos: Brown widow is by Leoadec (Wikimedia commons user) via Creative Commons attribution. Red widow is used via Creative Commons attribution and is by Florida Division of Plant Industry, Florida Department of Agriculture and Consumer Services, Bugwood.org
This highly-venomous spider should be kept by responsible, experienced adults only! Do so at your own risk. The author of this article is not liable and this article does not not contain medical advice. Immediately seek medical attention from a qualified professional if you are bitten by a black widow spider.
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