What we can learn by "moving" the specimen
September 11, 2026
Tokyo Sea Life Park displays not only live creatures but also a variety of specimens. Many people have probably seen animal skeletons and liquid-preserved specimens.
Some of you may have wondered, upon seeing the title, "Can specimens move?" Most specimens are fixed in place and cannot be moved after they are prepared, but some specimens can be moved, and moving them can reveal things that cannot be seen. This time, I will introduce a spiny lobster specimen that I prepared recently.
Spiny lobsters have a sound-producing organ near the base of their second antennae, which they rub together to produce sound. Spiny lobsters, in particular, are said to use this sound to intimidate other animals. However, they rarely exhibit this behavior in aquariums, so opportunities to hear the sound during opening hours are rare.
One day, a spiny lobster we were raising in the back room molted, so I decided to make a dried specimen of its molted shell, but several of its legs had fallen off. If I made a specimen of it as is, it wouldn't be able to properly show the structure of its body, so in such cases, I usually just throw it away. But then I remembered the sound-producing organs, and decided to try making a specimen where you could hear the sounds the spiny lobster makes by moving its antennae.
When creating a dried specimen with movable joints, a chemical called glycerin is used. By initially impregnating the specimen with glycerin, the flexibility of the joints can be preserved while it is dried.
I dried only the area around the antennae of the spiny lobster, and then used a paper towel to soak the joints with glycerin, resulting in a dried specimen with movable joints! By slightly wetting the sound-producing organs with water to prevent them from becoming slippery with the glycerin, I was able to create a specimen that still makes sounds. This was my first time soaking only a part of a body, rather than the whole, with glycerin, so I was worried, but I'm relieved that it turned out well.
This specimen, which we created, will be displayed irregularly at the counter of Information Desk. If you actually move it, you will find that the joints rub together nicely and produce a sound.
Even when they're not on display, we can prepare them for you, so please feel free to ask a staff member. Touching and moving the specimens might help you notice interesting aspects of the creatures, which could lead to even more fascinating discoveries when you see them in the aquarium.
[Tokyo Sea Life Park]