Leaping fish give evolution clue

A zebrafish uses its body like a spring - curling up then pushing off

Unlikely looking aerobatics performed by fish have given researchers an insight into how aquatic animals evolved to live on land.

Researchers discovered that at least six different types of fish are able to launch themselves into the air from a solid surface.
The team said this was an evolutionary snapshot of the transition from living in water to inhabiting land.
They published their findings in the Journal of Experimental Zoology A.
Lead scientist Alice Gibb from Northern Arizona University was surprised to find that every species she tested was able to jump.
It suggests that, rather than a rare adaptation that evolved in a select few species, the ability to leap on land is common among bony fishes. So many more of their ancient aquatic relatives might have invaded the land than had previously been thought.
"In my mind, that opens up the fossil record to re-interpretation," Dr Gibb told BBC Nature.
Slow motion leap

The scientist and her team are interested the behaviour of living fish, because they are trying to build up a picture of how modern species evolved and how they are related.

An amphibious fish called the mangrove rivulus, which spends some of its time on land, inspired this study.
"When we tried to move these fish in the lab [using nets], they would jump out of a net and back into the tank," she recalled.
This made Dr Gibb curious to see if the ability to take off was unique to species that had evolved to spend some of their time on land.
She and her team studied six unrelated species of fish, placing them on a flat surface and filming them with a high-speed camera.
"Every one that we studied was able to jump," said Dr Gibb.
One particularly intriguing discovery when they examined the footage was that mosquitofish (Gambusia affinis) and zebrafish (Danio rerio) used the same "tail flip" technique to perform their impressive leaps.
"The last common ancestor of the two species examined in this study lived about 150 million years ago," said Dr Gibb, "which implies that the behaviour is at least that old."