The 4-inch Chaco Golden Knee tarantula walks slowly up the arm of animal curator, Glen Marchant, who is smiling fondly at the resident spider. All ends well; no one is bitten.
Actually, the tarantula is a well-behaved beauty, with black, gold and orange hair resembling the colors in a calico cat's fur.
Unlike a cat, however, a tarantula's furry exterior is part of the rigid exoskeleton that supports and protects its body. Marchant explains that, as an arthropod, a young tarantula frequently sheds its entire exoskeleton through molting. During a fascinating process, a tarantula pops open its exoskeleton and crawls out, leaving behind what looks like a tiny fur coat. A full replacement furry exoskeleton is already covering its body, plus its large fangs and reproductive parts have also been replaced.
Since its new exoskeleton is temporarily more movable, the tarantula can quickly continue growing until the covering begins to harden again. A series of these molts will occur until the tarantula is fully grown, and adult tarantulas will molt about once a year.
About 900 different tarantula species live in temperate and warm climates around the world, Marchant says.
"We consider the New World tarantulas from North and South America—like Chaco Golden Knee—to be more docile, but they have irritating hairs," observes Marchant, although he doesn't seem to be bothered by them. "The hair on the abdomen is much more pronounced than before it molted."
The abdominal hairs have tiny barbs on them, and the tarantulas can flick them off. Some people can develop an allergic reaction, so children visiting YSI aren't allowed to touch the tarantulas, just in case. They nonetheless delight in learning about the furry critters through where the tarantulas are some of the animal ambassadors.
"The nice thing about my job is that Glen's already done all this research beforehand, and our curators pick out animals that work for the program we do," says YSI teacher Jessica Friedman, who handles the spiders and other critters with ease.
Marchant says he isn't worried about the tarantula biting him because her venom is weaker than a bee's—for most, not all people—although her fangs are large and can cause pain. Tarantulas sometimes dry-bite or rear up when giving a warning.
Like all spiders, tarantulas have eight legs. The two additional, shorter appendages by their mouths are pedipalps, which can be considered a spider's hands, especially while eating. As arthropods, they have jointed legs, as shown in the photos of Chaco Golden Knee. One of the several tarantulas at YSI lost its leg at a joint during a molt, but when it later molted again, the leg had grown back.
A female tarantula can live to about 30 years. She sees poorly through eight eyes that look like a cluster of bumps on her head, but she is sensitive to movement around her. These spiders have retractable hooks on their feet, like a cat's claws. As Marchant was holding the Chaco Golden Knee, he mentioned that he could feel the hooks, although it wasn't painful.
At YSI, the tarantulas receive a diet of crickets from the staff, while in the wild, their main diet consists of insects, lizards and other small creatures. They don't build webs, but are night hunters who use their sensitivity to vibrations to find prey. Tarantulas will also sometimes revert to cannibalism as a method of obtaining a meal.
Locally, Marchant says tarantulas are seen in the area of the Santa Cruz Mountains, although they are brown and "more gnarly" than their lovely cousins at YSI.
About this column: Each week, Susan Wiedmann will write about nature or outdoor activities enjoyed by local residents. Susan is a longtime freelance writer and photographer with a passion for capturing wildlife through her camera's lens. Please leave any comments about this article at the bottom of this page. You can contact Susan about possible topics atSusan@UpCloseWithMotherNature.com or at UpCloseWithMotherNature.com.