Dear Readers, yesterday we were lucky enough to get a preview of the new reptile and amphibian exhibit at London Zoo. The old reptile house hasn’t really been fit for purpose for a long time, and amphibians in particular are a major conservation focus at the Zoo. They developed the concept of EDGE species – animals which are genetically or behaviourally distinct in some way, and which are  critically endangered, endangered or vulnerable. Over 13% of amphibians fall into this category, not only because of the usual habitat destruction, but also because of diseases, such as fungal chytrid infections or ranovirus. The Zoo has been trying to concentrate on EDGE species, both to provide an ark for species threatened with extinction in their native range, to get a better understanding of how the animals live, and to hopefully reintroduce them back into the wild if a safe habitat can be found. The new reptile and amphibian house has 33 species, 15 of them EDGE species.

The new building has eleven distinct climate zones to accommodate the needs of the different species, and the enclosures have places where shy reptiles and amphibians can hide, where they can sun themselves and where their needs for burrowing, climbing or just hanging around can be met.

Entrance to the new reptile and amphibian house

I must admit that I’d been a bit sceptical lately about London Zoo and its conservation claims, but I think I am changing my mind somewhat, especially with regard to the less charismatic, smaller creatures. One of the stories concerns the Mountain Chicken frog, which lives only on the Caribbean islands of Montserrat and Dominica. Or, I should say ‘lived’, because in the 2000s chytrid arrived on the islands and within a few months had killed 80% of the frogs on Dominica, and all of them on Montserrat. The islands, where only a few years earlier had had tourists complaining that the calling of the frogs kept them awake at night, had fallen silent. 

Mountain Chicken frog (Leptodactylus_fallax) Photo by Tim Vickers.

Fortunately, some of the surviving frogs on Dominica were taken into a captive breeding programme involving zoos such as Gerald Durrell’s zoo on Jersey (which is so worth a visit if you’re on the island) and London Zoo, and it was there that the extraordinary life cycle of this frog was revealed. The females create a foam nest and lay a small number of eggs. When the tadpoles hatch, she continues to lay eggs, but these are infertile, and the tadpoles rely on them as a food source until they metamorphose, with the female and the male standing guard over them the whole time. They then spend a few days under the care of their parents before they leave to start their own lives. It’s thought that this brooding behaviour was the main reason for the ‘Mountain Chicken’ name, though when they were plentiful they were certainly a protein source for local people.

With perfect timing, some of the Mountain Chicken frogs have bred since they entered the new building, and we were shown a slide of a mother surrounded by tiny froglets. It’s hoped that once the captive population is big enough, some frogs will be able to be released into a semi-wild protected enclosure in Montserrat – the water there is heated to 31 degrees by solar panels, which is too high for the chytrid fungus to survive, but not too hot for the frogs.

Some species have managed to develop some immunity to chytridiomycosis (the disease caused by the chytrid fungus) so it’s hoped that over time the various frog species will do the same. You only have to look at the list of EDGE amphibians to see how endangered and vulnerable so many frog species are.

And now, who would like to see a Lake Titicaca frog (otherwise known as a Scrotum frog)?

Lake Titicaca (Scrotum) frog (Telmatobius culeus)

These can be huge frogs, growing up to 2 feet long, and as you can see they are very wrinkly – because Lake Titicaca is the highest freshwater lake in the world, it doesn’t have as much dissolved oxygen in the water as a lake at lower altitude would have. The extra surface area of the skin means that the frogs can absorb more oxygen, and it sometimes bobs up and down to get the water flowing over its skin. It’s very well adapted to its home, but not very well adapted to anywhere else and, unfortunately, trout have been introduced to the lake, and they eat frogspawn. This, plus increased pollution, the taking of frogs for the pet trade, for traditional medicine and the ever-present risk of disease has meant an 80 per cent decline in species numbers. Again, it’s hoped that this enigmatic frog will be happy enough to breed in the new building, as it has done in several other zoos.

London Zoo’s conservation programme works extensively with early-stage biologists in the countries where these frogs live, and helps to train and resource research into understanding the species and the threats that they face. They also help to set up education programmes so that local people can learn a bit more about how important the animals that they live with are, and how, so often, they aren’t found anywhere else in the world.

It’s not all about the frogs though – how about the Chinese Giant Salamander? This is one of the largest of all amphibians, with the largest animals weighing over 110 lbs and reaching 6 feet in length. They are functionally blind and depend on sensory nodes that run along their body to pick up vibrations from their prey, which includes practically anything aquatic, with a slight preference for crabs. They are territorial and have a complex series of mating displays with all kinds of chasing, rolling, posturing, inviting and general shenanigans.

Chinese Giant Salamander at Prague Zoo (Photo By Petr Hamerník – Zoo Praha, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=69436128)

Sadly, Chinese Giant Salamanders are critically endangered. In collaboration with Chinese scientists, one of the biggest species surveys ever undertaken was performed to try to find these animals in the wild, and the results were frightening – it took the equivalent of one year to find a single specimen. However, there are millions of captive Chinese Giant Salamanders, which are kept in crowded conditions with poor water quality until they are killed and eaten as a delicacy. They don’t breed well in these conditions, so they have historically been taken from the wild. Now, they have run out.

To complicate matters further, scientists think that there could be as many as nine different species, which can hybridise. As the giant salamanders sometimes escape, they are cross-breeding with the few remaining wild Chinese Giant Salamanders. What a mess!

Good afternoon! Chinese Giant Salamander

There are four giant salamanders at London Zoo, rescued from a post office in Coventry where they were being illegally smuggled. In fact, quite a lot of the reptiles and amphibians that arrive at UK zoos are victims of the illegal trade in the animals for collectors. Five salamanders were rescued, but one of them didn’t survive, a sad indictment of the way that living creatures are so often seen as commodities. Let’s hope that all the reptiles and amphibians survive and thrive in their new habitats.

The exhibit opens to the public on 29th March.

An outsize model of an Electric Blue Gecko (Lygodactylus williamsi), a critically endangered lizard from Tanzania