Legless Land Dwelling Fish Uses Camouflage to Avoid Predators [VIDEO]

In the rocky shoreline of Guam, Micronesia, a unique, unusual and tiny amphibious fish lives. The creature offers valuable insight in transition of an animal from water to land.

The legless, leaping fish is a marine species in all aspects expect for a bizarre fact that it spends most of its life on land. This leaping fish has managed to escape the scientific attention partially because they reside on rocks that are stroked repeatedly by violent waves.

But a team of researchers have put an end to this mystery by throwing light on the secrets of this fish.

According to the researchers at the University of New South Wales, these strange, legless, leaping land dwelling fish called Pacific Leaping Blennies use camouflage to stave-off predators, including crabs, lizards and birds.

The study led by researchers Dr. Terry Ord and Courtney Morgan, of the Evolution and Ecology Research Centre studied the leaping blennies in the tropical island of Guam.

"This terrestrial fish spends all of its adult life living on the rocks in the splash zone, hopping around defending its territory, feeding and courting mates. They offer a unique opportunity to discover in a living animal how the transition from water to the land has taken place," Dr Ord, of the UNSW School of Biological, Earth and Environmental Sciences, said in a statement.

The Pacific Leaping Blenny (Alticus arnoldorum) that is also known as the leaping rockskipper is oviparous in nature and survives by feeding on benthic algae (algae present in the layer of soil lining the water body). When disturbed these tropical blennies leaps from one hole to another in the rocks. They live on land during midtide and perform activities like foraging and mating. The 4-5 centimeters long fish uses its tail twisting behavior. In order to stay on land they have to stay moist as to breathe through the gills and skin.

To begin with, the researchers initially measured the color of five different fish population present on the island and then evaluated it with the color of the rocks the creatures dwelled on. Researchers noticed that the colors were virtually identical. The body color of the fish camouflages with that of the rock, which might be trait adapted to trick the predators and avoid attacks.

The researchers further checked if the background-matching lowered the rate of predation. For this they created a realistic looking model of blennies made of plasticine. Plenty of such models were placed on the rocks where the fish lived and they also placed a few on an adjacent beach where the body color of the fish made them look a lot more noticeable to the predators.

"After several days we collected the models and recorded how often birds, lizards and crabs had attacked them from the marks in the plasticine. We found the models on the sand were attacked far more frequently than those on the rocks. This means the fish are uniquely camouflaged to their rocky environments and this helps them avoid being eaten by land predators," said Dr. Ord.

Later, the body color of the closely related species. According to the study researchers, these strange tiny blennies offer an evolutionary insight of each stage of the land invasion by the fish.

Researchers found that the ancestors of the terrestrial fish had a coloration that corresponded well with the rocky shoreline, before they moved out of water, which made it easier for them to thrive in their new natural habitat.

The researchers documented their finding in the journal Animal Behavior.