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How dangerous are snakes in the Canary Islands?

Updated: Oct 13, 2022

The Californian king snake is a real 'killer' and is spreading rapidly in the Canary Islands. This leads to an alarming threat, as a research study has revealed.



The government of the Canary Islands warns, in addition to the increase of the Yemen chameleon (Chamaeleo calyptratus), about the significant increase in the population of the introduced American 'California king snake (Lampropeltis californiae)' on Gran Canaria.

For some years now there has been a snake problem on the beach and in the mountains of Gran Canaria. The American snake first appeared in 1998.


Since September 2019, a control and eradication program has been running as part of REDEXOS (Network for the Detection and Intervention of Invasive Exotic Species in the Canary Islands).

No ecosystem is free from the threat of invasive species. Humans can introduce a species that is not native to any ecosystem on earth, and once established, it can cause enormous problems.


In this case, however, it is also a very special kind of invasive species.

California king snakes came into vogue as pets some time ago. They are snakes that have no venom and rarely attack humans, which makes them interesting 'pets'. However, they are not cuddly animals to play with that can't really do much.

For this reason, more snakes have simply been released into the Canary nature in recent years.


Since then, they have built up stable populations and established themselves in ecosystems, and they have begun to compete with native species. In other words, they became an invasive species.


This biological invasion has caused considerable damage to the reptiles on the island of Gran Canaria. The island's herpetofauna - the term for the reptile diversity of a place - is under threat, and this is a serious problem. Because on Gran Canaria, as on all islands, there are a large number of species that only occur in this geographical environment and cannot be found anywhere else. They are endemic.


The artificially created 'competition' is now increasingly becoming a real struggle for survival for the native reptiles.


DETAILS

Researchers from the Island Ecology and Evolution Research Group have found that an invasive snake species poses a massive population threat to almost all reptiles native to Gran Canaria. In their article published in the 'Proceedings of the Royal Society', Julien Piquet and Marta López-Darias describe their comparison of habitats affected by the introduction of the invasive snake species with those that are not.


In 1998, Californian king snakes were introduced to the island of Gran Canaria; subsequently, some of them escaped or were deliberately released by pet owners. Since then, the snakes have mated, reproduced and colonised the island. In the current project, the researchers wanted to learn more about the impact of the snakes on the island's reptile population.

The researchers found that the reptile populations on Gran Canaria are declining. The study now concluded that there was a causal link between the presence of the snakes and the near extinction of giant lizards (90 per cent decline) and a halving of the population of geckos.


The results show the extent of the impact that an invasive species can have. The researchers point out that their findings also highlight the need for stricter regulations on the introduction of invasive species, especially in places with fragile ecosystems such as those found on islands.


 

Text: Chris Ernst | Foto: Montefuego Media Services / iStock

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