Tuesday, February 22, 2011

Vinegaroon Babies?

If you ever take a walk through the Insect Village at Pacific Science Center, you may have noticed the vinegaroon (vih-nih-guh-roon). This animal is one of our non-insect arthropods, and it is closely related to scorpions. Recently, when animal caretakers passed by the cage, they found themselves doing a double-take. When did the vinegaroon get so fat?!?!

Like all arthropods, vinegaroons have a hard exoskeleton that they must molt as they grow. When we looked at our vinegaroon a few months ago, we thought it appeared a little overdue for a molt. You can often tell when an arthropod is close to molting: Their bodies may expand or contract rapidly, they may change color, and usually the joints in between their exoskeletal plates begin to stretch out. This is what we noticed with our vinegaroon. But when it still had not molted after a few weeks, we started to get concerned.

Luckily, we got a timely visit from a former Animal Caretaker and insect specialist, Julie LaTurner. After a short observation, Julie had a hunch that something else was going on. She suspected that our vinegaroon was gravid, a term used instead of ‘pregnant’ for egg-laying species.

Few people have had much success getting vinegaroons to reproduce in captivity. A gravid vinegaroon excavates a chamber and walls herself in before producing her eggs. Our vinegaroon was probably seeking a place to burrow. In the exhibit cage, we use sand as a substrate, which is difficult for vinegaroons to dig through. But once we provided a better substrate for her to burrow, she went to work.

At first we were encouraged when the gravid vinegaroon immediately disappeared into her substrate. But then we again became concerned when we didn’t see her for a couple of weeks, so we checked through the substrate to make sure she wasn’t dead. Sure enough, we found her burrowed deep in the soil, with a large egg sac attached to her abdomen. Julie was right!

Inside the burrow, the vinegaroon will produce an egg sac that will remains attached to her body until her eggs are ready to hatch. When they hatch, the babies crawl out of the sac and onto their mother’s back where she protects them until they go through their first molt. After that, the babies leave the burrow. The mother stops eating while tending her eggs. She usually does not live long after the babies become independent.

Luckily, our vinegaroon’s second burrow is right up against the side of her enclosure, so we can check up on her through the clear walls (we keep it covered most of the time). We are not sure when her eggs will hatch. Little is known about raising vinegaroon hatchlings in captivity, and the odds are against us. But we will still root for the best, and hope to soon welcome new hatchlings into our collection.

While our gravid vinegaroon is on maternity leave, a younger, non-gravid vinegaroon is taking her place on-exhibit.


  1. Really excellent pictures Terry! Even if you can't see the egg sac.

  2. Great information! Someone gave us one for our library some time back, and she just laid an egg sac this morning, so I have been searching the internets for WHAT DO I DO??? Thank-you!

  3. Hi Ami

    I hope your vinegaroon does well. Did she actually leave an egg sac outside her body, or did she extend it off her side and now it's hanging there still attached?

    If it's separate from her, I would try to keep it as is, in the cage she was in, and trust her instincts to have put it in the best place she can.

    If it's still attached, and you don't have a lot of soil for her to dig in, you might want to offer her a place to dig. They like to be in little caves to incubate their eggs. If possible, leave her alone as long as you are sure she's alive. They are secretive at this time.

    That said, I wish we had better success with this. We did not get our Vinnie to hatch her eggs, so our advice is not necessarily what you need. We did a lot of searching an not many people have good success over time with this. If you get her to hatch them please let us know what you did!

  4. Thanks! She was just on gravel, and the sac was detached. She is walking around eating crickets. I softened some eco earth and sprinkled it on and around the sac, just a shallow layer, and I will add more tomorrow. I am worried about the crickets getting to it, but since she is eating I left a few in there - I'll probably remove all but one tomorrow. Like you, I'm not seeing that anyone has had much success, so we'll see what happens.

  5. Just a quick update: She keeps trying to dig into the corners, and of course gets stuck when she hits bottom. I piled a whole bunch of earth in the three corners she wasn't in today, hoping she will try one of those and be happier with the depth. The egg sac already looks dramatically different from two days ago - pronounced bumps where each nymph is, and more white than yellow. I saw one place that said they take a month to hatch, but I'm wondering if that is accurate! More seems to be known about giant vinegaroons and tailless whip scorpions that about our plain old desert dwellers.

  6. Ami, if you don't mind me asking, (I know this was a few months ago, so you may not see this... But ya never know) did your eggs hatch? I just recently got a Vinegaroon, and I am very interested in knowing as much as I can about them. Thanks in advance!