Smiley walking fish on show at Edinburgh Zoo

Picture: Edinburgh Zoo
Picture: Edinburgh Zoo
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IT’S had no luck so far trying to breed giant pandas – so now Edinburgh Zoo has turned its attention to a pair of “smiling” amphibians.

Populations of critically endangered axolotls, also known as Mexican salamanders or Mexican walking fish, have almost been wiped out due to loss of their natural habitat.

I am particularly fond of them because, as well as being very intelligent, they always look as if they are smiling

Gareth Bennett

Their unusual appearance features gills on the outside of the body which are in the shape of tiny feathery tendrils.

Scientists have long been fascinated by their extraordinary ability to regenerate lost limbs, leading to them being one of the most studied amphibians in the world.

The two males arrived at the zoo in July, where they were settled in for a few months before going on display.

The adorable pair have not yet been named but zoo staff said they may consider suggestions submitted over social media.

Gareth Bennett, senior presenter at Edinburgh Zoo, said: “Axolotl populations are diminishing at an alarming rate due to a number of factors, including increased urbanisation of Mexico which in turn leads to an increase in water pollution and the draining of their natural habitat.

“These fascinating creatures have also been used extensively in scientific research because of their ability to regenerate limbs. They are probably one of the most scientifically studied salamanders in the world.

“It is wonderful to be able to have axolotls at the zoo.

“We have successfully bred this exceptional species previously and hope to do so again in the future as it is incredibly important to maintain healthy captive populations to ensure they do not become completely extinct.

“I am particularly fond of them because, as well as being an incredibly intelligent species, they always look as if they are smiling.”

The species was listed as critically endangered on the International Unions for the Conservation of Nature’s RED List in 2010.

But a four-month search in 2013 failed to find any surviving individuals in the wild leading scientists to fear they may be extinct in their source habitat.

In the wild they are only found in the lake of Xochimilco, near Mexico City.

And the axolotl is unusual for amphibians because it reaches adulthood without metamorphosing like a tadpole.

And instead of evolving like most other amphibians and migrating to land, the species keeps its gills and prefers to live its whole life in fresh water.

Its most defining characteristics are branch-like gills which protrude from the neck on either side of the head. The gills are covered in feathery filaments which increase the surface area for gas exchange, this in spite of the fact that they also develop lungs, which are very rudimentary.

The name “axolotl” is thought to have originated from the Aztec word “atl”, meaning water, and “xolotl”, meaning monster.

And whilst they may not look very appealing, axolotls formed a staple part of the ancient Aztecs’ diet.