Tarantulas: fascinating pets, but not for everyone

By Gary Raham
Nature Columnist

For pet owners looking for warm and furry things that signal affection by cuddling or nuzzling, tarantulas may not be their choice.

On the other hand, if someone wants to observe a creature both beautiful and elegant with the ambience of an otherworldly alien, a giant hairy spider may make a perfect companion. Teachers often find them to be an exciting --and educational, of course--addition to the classroom.

Tarantulas, an ancient lineage of mygalomorph spiders* that sometimes reach the size of a dinner plate, do not pose great dangers to their owners, but they do need to be treated with care and respect. Females can live up to 20 years, so they also represent a long-term pet care assignment. Most are tropical species and can't be kicked out the front door when one gets bored with them. Some populations have been endangered in the wild because of over-collecting--most notably the Mexican redknee (various Brachypelma species), that sport bright red knees or rumps. Many species are now bred in captivity and can be purchased as young spiderlings.

Will tarantulas bite? Spiders do possess large fangs filled with venom used to paralyze their normal prey. Because tarantulas are large, their three-quarter-inch fangs can break the skin. The good news is they don't usually bite unless they are badly frightened or abused, and the bite is usually no worse than a bee sting. Some people may have allergic reactions to a spider's bite, and species like the African Baboon spiders (Hysterocrates) do produce potent venom.

The biggest problem that results from handling tarantulas, however, is that the spiders themselves often get injured. Their organs float in a bath of blood and fluids only contained by the walls of their external skeleton. Should they splat on the floor, they may bleed to death before the body can heal itself. Tarantulas also possess another line of defense especially suitable for discouraging annoying vertebrates: urticulating hairs that they can shoot from their abdomens. These can itch, cause allergic reactions or even become imbedded in your eyes. Some species are more apt to shoot hairs than others. If you see adults with bald spots on their rear ends, most likely they have been busy discouraging an annoying handler or other potential enemy.

What does this noncuddly potentially allergenic creature offer its caretaker? Many species sport eye-pleasing, colorful markings. Arboreal (tree-loving) species may be fairly active, and some burrowing species are creative architects worthy of observation. Should a pet owner choose to buy young spiderlings, he or she will be treated to the spectacle of watching the development of a typical arthropod that must periodically shed its skin in order to grow larger. And, of course, tarantulas make great conversation topics at cocktail parties and family get-togethers.

Tarantulas eat sparingly once every one to three weeks, but they do require live food. Crickets and flies provide more suitable meals than mealworms. Bait shops and some pet stores often carry crickets and mealworms. Wingless fruit flies can be purchased from biological supply houses for raising spiderlings, and these flies can be cultured fairly easily in plastic vials. Pet owners need to figure out their supply lines for these products before purchasing a spider.

Tarantulas also require a relatively small cage that can be sealed securely and a source of water. They like relative humidities of around 70 percent (especially tropical species) and need sterile bedding material like vermiculite, commercial top soil, pet bark (not cedar) or peat (but not local garden soil). Spiderlings can be raised in small vials and containers lined with paper towels that are changed regularly.

What should a beginner buy? Dr. Linda Ravor, a Cornell entomologist and spider lover, lists several recommended species on her web site at www.entomology.cornell.edu/SpiderOutreach/Tarantulas.html. Beginners will probably want fairly nonaggressive, slow-moving species. She favors arboreal species like Pinktoes (Avicularia sp.), Costa Rican Zebras (Aphonopelma seemanni) and Honduran curly hairs (Brachypelma albopilosum). On the other hand, she says, a common species found in pet stores, the Chilean Rose Hair (Phrixotrichus spatulata), is so boring to watch you might as well have a pet rock.

Avoid buying males, which are commonly sold in pet stores. They possess bulbs on the end of their pedapalps--manipulating limbs near the mouth --and tarsal spurs on the first pair of walking legs used to fend off females who are more hungry than amorous. They die young, after spending a year or two trying in vain to find a female.

A tarantula owner can expect to spend $25 to $70 or so for this companion plus $20 for overnight shipping. Spending an additional $8 on a good reference like "Marshall's Tarantulas and Other Arachnids" (1996) is also wise. Arachnid lovers--and readers should know by now if they are--an then settle down and watch how these fanged and segmented holdovers from the Paleozoic do their thing.

* Spider purists will know that true tarantulas are spiders in the genus Lycosa, but the term tarantula commonly refers to tropical spiders in the family Mygalomorphidae.