Secrets of the legless, leaping land fish (w/ Video)

December 2, 2013
The legless, leaping land fish
A male Pacific leaping blenny on the island of Guam. Credit: Courtney Morgans/UNSW.

One of the world's strangest animals – a legless, leaping fish that lives on land - uses camouflage to avoid attacks by predators such as birds, lizards and crabs, new research shows.

UNSW researchers, Dr Terry Ord and Courtney Morgans, of the Evolution and Ecology Research Centre, studied the unique – Pacific leaping blennies - in their natural habitat on the tropical island of Guam.

Their study will be published in the journal Animal Behaviour.

"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," says Dr Ord, of the UNSW School of Biological, Earth and Environmental Sciences.

The researchers first measured the colour of five different populations of the fish around the island and compared this with the colour of the rocks they lived on. "They were virtually identical in each case. The fish's body colour is camouflaged to match the rocks, presumably so they aren't obvious to predators," says Dr Ord.

To see if background matching reduced predation, the researchers created realistic-looking models of blennies out of plasticine. "We put lots of these model blennies on the rocks where the fish live, as well as on an adjacent beach where their body colour against the sand made them much more conspicuous to predators," says Dr Ord.

This video is not supported by your browser at this time.

"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."

The researchers then studied the body colour of closely related species of fish, some of which lived in the water and some of which were amphibious, sharing their time between land and sea.

"These species provide an evolutionary snapshot of each stage of the land invasion by fish," says Dr Ord.

The similarities in colour between these species and the land-dwelling fish suggest the ancestors of the land-dwelling fish already had a colouration that matched the rocky shoreline before they moved out of the water, which would have made it easier for them to survive in their new habitat.

The Pacific leaping blenny, Alticus arnoldorum, is about four to eight centimetres long and leaps using a tail-twisting behaviour. It remains on land all its but has to stay moist to be able to breathe through its gills and skin.

Explore further: Landlubber fish leap for love when tide is right

More information: "Natural selection in novel environments: predation selects for background matching in the body colour of a land fish." Courtney L. Morgans, Terry J. Ord. Animal Behaviour, Volume 86, Issue 6, December 2013, Pages 1241–1249

Related Stories

Landlubber fish leap for love when tide is right

August 30, 2011

One of the world's strangest animals – a unique fish that lives on land and can leap large distances despite having no legs – has a rich and complex social life, a new study has found.

Flipping fish adapt to land living (w/ Video)

July 5, 2013

Researchers have found that the amphibious mangrove rivulus performs higher force jumps on land than some other fishes that end up on land. This new study shows that unlike the largemouth bass, which makes very few excursions ...

Nothing to see here

November 11, 2013

( —"Blend in" appears to be the mantra for male Bahamas mosquitofish that live near predators. After all, fish with brighter, more colorful fins or patches are more conspicuous – and standing out with predators ...

Recommended for you

New gene map reveals cancer's Achilles heel

November 25, 2015

Scientists have mapped out the genes that keep our cells alive, creating a long-awaited foothold for understanding how our genome works and which genes are crucial in disease like cancer.

Study suggests fish can experience 'emotional fever'

November 25, 2015

(—A small team of researchers from the U.K. and Spain has found via lab study that at least one type of fish is capable of experiencing 'emotional fever,' which suggests it may qualify as a sentient being. In their ...

How cells in the developing ear 'practice' hearing

November 25, 2015

Before the fluid of the middle ear drains and sound waves penetrate for the first time, the inner ear cells of newborn rodents practice for their big debut. Researchers at Johns Hopkins report they have figured out the molecular ...

How cells 'climb' to build fruit fly tracheas

November 25, 2015

Fruit fly windpipes are much more like human blood vessels than the entryway to human lungs. To create that intricate network, fly embryonic cells must sprout "fingers" and crawl into place. Now researchers at The Johns Hopkins ...


Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (3) Dec 02, 2013
Is the principle of camouflage still so controversial that it needs to be tested more? I would have moved some to see what happened when the camo didn't match.
1 / 5 (3) Dec 02, 2013
Land fish. No one is safe now.
1 / 5 (3) Dec 02, 2013
Land fish. No one is safe now.

"We're going to need a bigger boat/truck." -- JAWS IV: Terra Firma

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.