Monday, November 5, 2012

Dissection at the Science Center!

Warning: This post contains graphic images of a bat dissection.


Kat and her bat specimen in the AZ Science Center's lab.

Last month, Kat and I spent quite a bit of time learning about bats and their diets and habitats. One of the highlights of our research was when we compared bat skeletons to the skeletons of other creatures. The most interesting comparisons came when we looked at bats, birds, and humans. The first similarity that comes to mind when comparing bats with birds is their shared ability to fly. Both skeletons are light enough to facilitate that, and some of their bones are fused together in similar ways in order to decrease the amount of weight in each skeleton.


A comparison of human, bat, and bird skeletons.

We were most surprised however, when we compared the bat skeleton to that of a human. The similarities were quite striking when comparing the ribs, arms, feet, and fingers. The curvature of the spine is also similar, as is the general frame from shoulder to pelvis. What was really fascinating, was looking at how the elongated fingers form the wing. While a bird's "hands" have fused together to form the wing tip, a bat's arms and fingers have dramatically lengthened. The bat's wing is essentially a giant hand! These fingers actually allow for greater agility in flight; the slight bending of one finger will allow the wing to bend, causing an immediate change of direction in flight.

We were able to take an even closer look at the bat and its skeletal structure when we were given the opportunity to participate in a bat dissection at the Arizona Science Center! The AZ Science Center offers many fantastic learning opportunities for kids, everything from science camps to home school classes. They provide an excellent learning environment with friendly, qualified staff, and give kids access to resources they wouldn't otherwise be able to use (like this killer lab!). We try to take advantage of these opportunities whenever possible.

In this dissection, we would be working with a specimen of the Mexican Free-Tailed Bat. This was great because we had already spent quite a bit of time observing them between the Phoenix Bat Tunnel and our own neighborhood roost.

Mexican Free-Tailed Bat specimen in a jar of Formaldehyde. 

After a brief overview of bats and their anatomy, it was time to get to work! The first thing we did was identify the external parts of the bat. We looked for the thumbs, feet, fingers, tail, head, and skin. We numbered each finger and looked at our own to see how they compared. We looked at the nose and ears of the bat, and examined its mouth and tongue closely while talking about how these features helped with its diet of insects. We even saw the ridges in the ears which help the bat create detailed imagery of its environment when using echo location!

Our Mexican Free-Tailed Bat prepped for dissection.

When we were finished with our external identification, it was time for us to make the first cut into the bat. We made one long incision down the center of the torso, then cut two horizontal lines: one on top and one on the bottom, essentially creating the shape of a very large I. This allowed us to open the chest cavity with two flaps, so that we could have easy access to the internal organs.


Using surgical scissors allowed us to cut through the tough skin and
muscle that protects the internal organs.

Once the chest cavity was open, the kids were able to use their tweezers to gently remove and identify the internal organs. They pulled out the intestine, lungs, kidneys, liver, and heart. It was really neat to see the incredible similarity in these organs to our own. It was the first time either of us really had the opportunity to look at these inner organs up close.


Skin and muscle have been opened, providing a window to the inside of the bat

The kids really enjoyed the bat dissection. Getting a good look at an animal we learned so much about was really a great experience. In a way, we were even able to learn a bit more about ourselves in the process, and the many ways that we relate so beautifully to the rest of the animal kingdom.




Of course, it was really cool to see and identify so many parts of the bat's anatomy, too!



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