Wednesday, April 23, 2008
It’s easy to overlook Skippy the Mudskipper as you tour the Aquarium’s 2nd floor exhibits. His home is right under a sign that reads “Deadly Snakes of the Seas”. Skippy’s tank mates get first billing on the display so most visitors concentrate their gaze on the underwater portion of the exhibit to watch the sea snakes as they undulate through the water. Skippy and his mudskipper buddies however can be found in the above water portion of the exhibit amongst the plants and rockwork. It’s an odd paradox that one has to look underwater to see snakes and above water to see fish. What makes this mudskipper special enough to have his story told in this blog is that Skippy is a fish that acts more like a dog when interacting with his human caretakers.
First things first—What is a mudskipper?
The Aquarium of the Pacific’s Online Learning Center describes mudskippers as—
“— torpedo-shaped gobies. They have muscular, arm-like pectoral fins that function as legs when they are on land; two dorsal fins; and, depending on the species, their anal fins can be joined to form a sucker that aids in climbing. A muscular tail allows them to “skip” over land. Mudskippers also have lateral lines on their foreheads. Early in the larval life of these fish, their eyes migrate to the top of their head, where they are located close together. Internally, their protuberant eyes have cones above for color vision and rods below for monochromatic vision, allowing the fish to see both above and below water at the same time. Mudskippers have adapted to an amphibious lifestyle so that they can shuttle back and forth from the water to land. Many of these fish actually spend 90% of their time on land! When in the water, they breathe with their gills as most fish do. Before climbing out onto land, these fish fill their over-sized gill chambers with water, creating an oxygen tank that allows them to breathe out of water. On land, these fish also moisten their gills periodically by wiping them with their fins. To get additional air, mudskippers can also breathe through their blood capillary-rich skin, and blood-rich membranes in the back of the mouth and throat. They often keep their tails in water and roll in puddles to keep their skin moist. Mudskippers’ fins have adapted so they can walk, jump, swim, and climb. Their pectoral fins are used to move about on land where they don’t actually walk, but instead move in little hops by keeping their bodies rigid and jerking forward on their fins. This movement is called “crutching”. The pelvic fins of some species are joined together under the body to form a type of sucker that helps these fish creep up rocks and mangrove roots.”
All of the above is interesting in itself but to me what make mudskippers extremely endearing is their behavior. They jockey for position on the rocks above the waterline by making little “skips” and will display their iridescent blue tipped dorsal fins to intimidate other mudskippers like dogs will raise the fur on their backs in a threat display to establish hierarchy. Skippy takes this dog imitation one step further by climbing up the side of the rock wall and out of the tank when called by Aquarium staff when the display is opened from the top for cleaning and feeding. Aquarium Vet Tech Colleen trained this behavior to the point that she can call the little mudskipper up onto the ledge at the top of the exhibit where she can feed Skippy in peace without having to worry about the venomous sea snakes below. Of course its one thing to describe how Skippy climbs up out of the tank, its another thing to actually see it done so I’ve included in this blog a video clip of Skippy the Mudskipper:
The next time you’re on the 2nd floor of the Aquarium in the Tropical Pacific Gallery make sure to check out Skippy and his mudskipper buddies in the sea snake exhibit. They are quite entertaining to watch.
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