Tarantulas In Our Backyard

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Lately, I’ve been hunting for tarantulas in our backyard.  Tarantulas are common in the desert surrounding Tucson but finding them takes a bit of skill.  Although tarantulas are more or less strictly nocturnal, I hunt for them in broad daylight.  I don’t search for the spiders, I search for their burrows.

One of these huge spiders will dig a burrow that he or she enlarges as he or she grows.  There are other creatures in our desert that dig burrows, including several species of mice, kangaroo rats, and packrats.  Tarantula burrows are distinctive.  One typically consists of a sharply defined hole, an inch or more (2.5 cm or more) in diameter.  It is distinguishable from other creatures’  burrows because the tarantula leaves a “signature,” a fine mesh of silken strands across the burrow’s entrance.  That little bit of silk announces the tarantula’s presence even if the spider is underground and out of sight.

Poking around my backyard, I found at least two burrows.  In order to see the tarantulas I had to return in full darkness.  At night, a tarantula sits, either on the edge of the burrow or partially in and partially out of the burrow, waiting for something edible, like a beetle or a centipede, to happen along.  If prey comes close enough — within a tarantula’s body length or so — the tarantula leaps out of the burrow, seizes it, and devours it.  Like all spiders tarantulas have venomous fangs (“chelicerae”) which they use to good effect to dispatch their victims.  Tarantula venom, by the way, poses no threat to humans.

It took a few attempts but I was able to photograph one tarantula as she sat just below the lip of her burrow with her forelegs protruding.

In this image she is facing the camera with her two forelegs flanking her pedipalps, modified mouth parts that resemble a fifth pair of short legs.  She uses her pedipalps as “hands” to clasp objects including her prey.  In between the pedipalps you can make out her chelicerae.  Two of her eight eyes glow as the reflect my camera’s flash.  Her legs, pedipalps, and chelicerae are covered with long, coarse hairs.  These hairs are important sense organs.  Tarantulas cannot hear but they are exquisitely sensitive to vibration.   She senses the slightest vibration through her many hairs.  Thus, although she cannot hear me approaching, she definitely knows that I am near her.

My wife, Louisa, nicknamed this tarantula “Esmerelda.” I’ve returned to Esmerelda’s burrow on several occasions.  She is a timid monster, never emerging fully and usually retreating after I take one or two photos.

A few evenings ago I was surprised to find a second tarantula sitting close to Esmerelda’s burrow.  Whereas Esmerelda has reddish hairs on her legs this spider has legs that are two-toned, light at their lower ends and dark near the spider’s body.  This is a very large tarantula, easily the size of my hand.

I believe that this second tarantula is a male who came to court Esmerelda.  The dark legs and abdomen are indicative of a male, although the pale lower parts of this spider’s legs are a bit unusual.

During the summer, mature male tarantulas leave their burrows and wander in search of mates.  If this spider is a male it would be about 10-12 years old.  Male tarantulas generally die after breeding.  Females, like Esmerelda, can live up to 30 years or so.

I check on the tarantulas’ burrows each evening.  There’s a second burrow that is occupied by another tarantula, that I’ve just begun to investigate.  With any luck, one of these evenings, I’ll be able to make an image of one of our resident tarantulas completely outside of his or her burrow.

Images made with a Canon 5DS-R, 180mm f3.5 L Macro Lens, illuminated by Canon Ring Light, M setting.  First image, ISO 200, f11 @ 1/160.  Second image, ISO 100, f8 @ 1/160.