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Mudskippers are amphibious fishlike creatures that use their short muscular pectoral and pelvic fins to “walk” on mud in a series of skipping like steps, thus their name. These unique about 30 cm long creatures, typically live in intertidal habitats where the water level changes with each tide change (Hafer, 2016, p. 66). Most other intertidal fish survive tide changes by taking refuge under wet seaweed or in tide pools. Mudskippers are different. They exhibit many unique adaptations to their muddy environment that are rarely, or never, found in other intertidal fishes (Marsh, 2015).

This creature that looks like they came from outer space can move surprisingly rapidly on muddy surfaces. If they become aware that a potential predator is near, they can even bore into the ground for protection, or they may flee into the safety of the water. Once in the water, they can propel their streamlined fish body rapidly with its fish tail like any well-designed fish (Petrillo, 2011, p. 1).

The mudskipper pectoral fin differs from that of most all fishes in that it is elongated and protrudes out from the fishes’ body wall. This unusual pectoral fin design includes two fin segments (the radials and the rays), and two movable hinge joints: a `shoulder’ joint where the cleithrum (a large bone that extends upwards from the base of the pectoral fin and anchors to the cranium above the gills) meets the radials, and an `intra-fin’ joint where the radials also meet the rays. This ingenious design allows it to not only walk on dry land, but even to effectively climb trees. They are, in fact, the only known fish that can climb trees! In short, although called an “ugly animal,” they are ingeniously designed creatures so well suited to their intertidal environments that they now thrive on four continents (Marsh, 2015, p. 20).

Although mudskippers can swim, they live out of water and in the atmosphere about 90% of the time. They breathe through their skin, forcing air to pass through their skin, which traps air to supply oxygen to their cells (Rake, 2015, p. 28). Although they have gills, they use them not to breathe, but rather to excrete waste products. They also have gill chambers that they use to store water, allowing them to remain out of the water for significant periods of time.

Their eyes protrude from their head and extend upward so that they can see out of the water while they are still safely submerged. Their eyes can swivel in almost any direction, allowing them to have a wide panoramic field of view. They see exceptionally well both in the air and in the water, a rare feat for any animal (Petrillo, 2011, p. 1).

Mudskippers both breed on land and build their nests underground. After their eggs hatch, if the oxygen in the nest becomes low, the parents are able to gulp air from outside of the nest in their balloon like pouch mouth, and then release the air into their underground nest air chamber (Hafer, 2016, p. 68). Their diet, which consists of small insects like flies, plus small crustaceans, helps to keep the insect population under control (Rake, 2015, p. 29).


No fossil evidence exists for their putative evolution from some pre-mudskipper organism. Scientists are not even able to satisfactorily classify modern mudskippers into a family, leaving their evolution to pure speculation. They were once included in the Oxudercinae subfamily, within the family Gobiidae (gobies), but recent molecular studies do not support this classification. Darwinists are now stymied about their phylogeny, and can only speculate concerning from what and how they could have evolved. A major problem for evolution is that the first mudskipper in the fossil record is morphologically a modern mudskipper.

Long assumed to be a transitional animal between a swimming fish and a tetrapod (four footed) animal, a recent study by Kutschera and Elliott (2013, p. 1) concluded that, although some walking fishes such as mudskippers “shed light on the gradual evolutionary transition of ancient fishes to early tetrapods … they are not the ancestors of tetrapods, because extant organisms cannot be progenitors of other living beings.” As Polgar, et al. note, more study is required to detail the evolution of the mudskipper (2014, p. 179).

Many experts have hypothesized that fish fins evolved into terrestrial limbs, a theory that also does not fit the facts (Clack, 2012, p. 136). For example, the earliest tetrapods were not pentadactyl (having five fingers and toes) as are modern tetrapods, and the fossil evidence does not support the fin to limb evolution (Clack, 2012, pp. 136-137).


In short, the mudskipper is not a fish that evolved legs or an amphibian that evolved to look like a fish, but a graceful well designed swimmer in water that gets along so well out of water that they spend most of their life on land and thrive in large areas of the world.  We have no evidence of fish-fin to tetrapod limb evolution, and the mudskipper does not help to explain the major missing links that can bridge the two structures. Like the duck-billed platypus, the mudskipper contains a unique mosaic of features found on many different animals. And this situation is bad news for evolutionists.


Clack, Jennifer. 2012. Gaining Ground: The Origin and Evolution of Tetrapods. Bloomington, IN: Indiana University Press.

Hafer, Abby. 2016 The Not-So-Intelligent Designer: Why Evolution Explains the Human Body and Intelligent Design Does Not. 2016. Cascade Books, an Imprint of Wipf and Stock Publishers. 266 pages.

Kutschera, Ulrich and Malcolm Elliott, 2013. Do mudskippers and lungfishes elucidate the early evolution of four-limbed vertebrates? Evolution: Education and Outreach. 2013, 6:8.

Marsh, Laura. 2015. Ugly Animals. Washington D. C. National Geographic.

Petrillo, Brett. 2011. “Mudskipper: A Partially Evolved Fish?” BP’s Fuel for Thought.

Polgar, G., L. Zane, M. Babbucci, F. Barbisan, T. Patarnello, L. Rüber, and C. Papetti. 2014. “Phylogeography and Demographic History of Two Widespread Indo-Pacific Mudskippers (Gobiidae: Periophthalmus).” Molecular Phylogenetics and Evolution, 73:161-176.

Rake, Jody S. 2015. Mudskippers and other Extreme Fish Adaptations. North Mankato: Capstone Press.

Jerry Bergman
December 2016

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