A Molting Tarantula

Last week, one of our Chilean rose tarantulas (Grammostola rosea) molted. This event is one of the most dramatic non-emergencies an Animal Caretaker is apt to encounter. In fact, the process is so stressful looking, it's common to confuse a molting tarantula with a sick or dying one. Often it’s hard not to intervene and 'help'.



Prior to molting, a tarantula builds a silk nest and lies down on her back in the middle of it. She appears to be in her death throes, but then with almost impossible effort, she bursts her way out of the old skin, revealing a velvety, fresh new spider underneath.

The picture above shows our spider, Roslyn, (on the left) immediately after she freed herself of her old skin. She is waiting for her legs to fully expand. Every few minutes she stretches all the legs on one side or the other, probably as she pumps fluids into them to fill out her skin.

For several hours after molting, the spider is totally helpless. Her new exoskeleton needs to expand and harden. Since spiders usually support their full weight on their legs, this is a problem; her legs are too weak to support her body. The tarantula must stay on her back until her legs are strong enough to support her body.

The lighter colored form, on the right, is Roslyn's old skin, lying empty beside her.

In related arachnid news, a newly discovered species of tarantula from the Amazon has been named after a Beatle. Imagine!


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The Tale of the Undead Beetles

In the life of Animal Care, we have to deal with the fact that our animals occasionally die. While this is difficult to accept emotionally, it’s usually easy to determine whether an animal is dead or alive. But not always. In the spirit of Halloween, we bring you the "Tale of the Undead Beetles!"

We feed our herbivorous arthropods every other day: checking on their water, removing old food, and looking over the health of the animals in their cages. Some herbivores are more active than others. While we can usually rely on the Darkling beetles and Velvet ants to be moving around their cage, sometimes the cockroaches and Blue death-feigning beetles are remarkably still. This was the case one morning recently, when Animal Caretakers Katie and Lauren were making their rounds. Almost all of the Blue death-feigning beetles (Cryptoglossa verrucosus) were completely motionless. We gave them a nudge to see if they were alive. The beetles fell over, apparently dead.

You can probably guess by the name of these insects that appearances can be deceiving. Unsure of a prognosis, Katie and Lauren collected five visibly dead beetles and placed them off exhibit for observation. The Animal Caretakers weren’t very hopeful. These beetles looked VERY dead.

Two minutes later, one of the beetles was up and walking around the box! Hooray! But the rest were surely dead. Ten minutes later, another one stirred! Hooray, hooray! After about an hour, the most cautious of the beetles finally realized that the danger had passed. It was safe to return to the world of the living. Eventually all of them proved to be very much alive.

Of course, faking death is a defense mechanism for Blue death-feigning beetles. However, when it comes to tricking the people who take care of you, that strategy may not always work in your favor.


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