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Crimes Against: Invasive Pets

Alien Invasion!


Humans have a long-standing fascination with the keeping of exotic animals, records dating back as far as 4000BC show Ancient Egyptians kept wild birds for non-food purposes including for the purpose of sacrifice 

Ancient Romans witnessed the killing of thousands of Bears, Panthers, Leopards, Lions and Elephants in the Colosseum, animals captured and trafficked on the request of orator and politician Marcus Caelius Rufus, demonstrative of an ancient obsession with exotic wild animals.

Indeed, the fascination with the keeping and exhibition of exotic animals has been demonstrated many times throughout ancient and modern history.  

In the 1980s, the exotic pet trade boomed, resulting in an explosion in the popularity of reptiles as pets across the Western World, one example of this being the Burmese Python. 

a statue of a snake

The Burmese Python can reach upwards of 23 feet and up to 75kg (nearly 12 stone) – though the heaviest captured weighed-in at 97.5kg (over 15 stone!) by which point many owners find themselves unable to care for the large snakes.  This often results in their release into the wild.  

Biologists Ian Bartoszek, right, and Ian Easterling, center, with intern Kyle Findley show the 17.7ft, 215lb female Burmese python captured in the Florida Everglades. Photograph: Jc Findley/Conservancy of Southwest Florida via AP

In the Everglades (Florida, USA), climate and environmental conditions allow the survival of released Burmese Pythons.

In 1992, Category 5 Atlantic Hurricane ‘Andrew’ struck the Bahamas, Louisiana and Florida.  

A man holding an animal in front of the devastation caused by a hurricane

Among the devastation caused was the total destruction of a Python breeding centre in the Everglades.  The escape of Burmese Pythons from the wreckage of this facility combined with the numbers of released pets led to the establishment of a significant breeding population of Burmese Python in the Everglades.

A black and white newspaper cutting

Today, it is near impossible to estimate the number of Burmese Pythons living wild in the Everglades, largely due to the inaccessibility of much of the area for conducting research, and also due to the highly effective mottled-brown camouflage of the Burmese Python.

Biological Consequences:

The Burmese python is native to Southeast Asia.  As an invasive species, Burmese Python pose a huge threat to Florida wildlife and there has been an extensive decline in the population of native mammals and reptiles, from racoons to alligators (yes, really!). 

Research findings suggest that in the space of only 15 years from 1997, the Racoon population dropped by as much as 99.3%, Opossums by 98.9%, and Bobcat by 97.5%.

Find out more here

Further research fitted Marsh and Cottontail rabbits with radio transmitters.  It was discovered that 77% of rabbit deaths over a 12-month period were caused by Burmese Pythons. Read more here 


As the Burmese Python is such a recognised nuisance to the Everglades ecosystem, barriers to hunting them have been removed by the Florida government.  

Hunting of invasive reptile species is allowed on both private and public land (although some restrictions and guidance apply on public land), and even incentivised by the running of hunting competitions and events.  

The annual Florida Python Challenge currently offers a grand prize of $10,000, with winning categories for most pythons and longest python killed.  Prospective Python hunters do not even require a hunting permit/licence.

Although hunting does remove a relatively small number of Burmese Pythons from the ecosystem (eg. 231 in 2022 read more here), it is an ineffective method of population control, given that just one female python may lay 50-100 eggs per year. Because of this, more mitigation methods are being considered…

The Florida Fish and Wildlife Conservation Commission recently introduced their ‘Detector Dog Team’, using specially-trained dogs such as Labradors and Spaniels to hunt down and help their handlers remove Burmese Pythons from the wild.

Another new approach to mitigation is the potential use of genetic modification.  Genes of captured snakes could theoretically be modified prior to their release into the wild.  For example, male snakes could be genetically modified to produce only male offspring, or the genome could be manipulated to cause death in any female offspring.  This would severely impact the breeding population

Find out more here 

Invasive-Native Paradox:

Paradoxically to the booming population of Burmese Python as an invasive species in the Florida everglades, the species is experiencing rapid population decline in its native habitat in Southeast Asia. The species is now listed as “vulnerable” on the IUCN red list and may eventually become extinct if not protected. Main reasons for their decline include being hunted for food and for their skin, but also habitat degradation in upland areas. 

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UK Invasion?:

It is not unlikely that at some point in the future, the UK could face a similar problem to Florida. Burmese pythons are popular pets in the UK and it is not uncommon for owners to release them into the wild. Currently (2023), when Burmese pythons are released into the wild, uncaptured snakes soon die due to unsuitable temperatures.  However, current climate change predictions forecast an increase in temperature to a point at which Burmese pythons could survive and establish a stable reproducing population in the United Kingdom.


There are approximately 2 million pet snakes in the UK, the most popular of these being Corn Snakes and Royal Pythons.  When temperatures reach a comfortable survival range for such animals, then their release into the wild could lead to the establishment of a breeding population, severely impacting our native wildlife and ecosystem.  

One Part of a Wider Issue

Burmese Python are just one example of the threat posed by the release of pets into an ecosystem to which they are not native.

Another example of an invasive pet is the Giant African Land Snail, the invertebrate reaches up to 20cm and may weigh as much as 1kg.  Giant African Land Snails reproduce rapidly (each laying up to 1200 eggs per year from a single mating) and consume large amounts of vegetation.  They are invasive in the Caribbean (as well as in Florida) and cause devastation to native fauna and crops, reducing the number of producers in the food chain, on which native species (as well as humans) depend (read more here) It is thought that the snails were introduced to the Caribbean by hitching rides on ships carrying potted plants, as well as by the release of pets into the wild.

The Global Invasive Species Database (GISD)  provides a source of information about alien and invasive species that negatively impact biodiversity.

What can you do to help?

It is important before taking on any animal as a pet to thoroughly research and carefully consider the requirements of the animal, and whether you are truly prepared to fulfil these requirements for its entire lifespan.

a close up of an animal

It is completely understandable that unexpected events may impact a person’s ability to care for any animal, especially one with such a long lifespan as a Burmese Python. 

Should circumstances change and you are unable to continue to care for the animal, then the responsibility for finding the animal a suitable new home lies with you.  Whether this be via a local expert, or rescue centre, there is always an option that does not lead to the release of a species into an ecosystem that is unable to cope with the invasion.  

There are many specialist rescue centres for reptiles and other exotic animals in South Wales and throughout the United Kingdom.  Animal Rescue and Welfare charities such as the RSPCA are able to advise, along with your nearest specialist exotic animal veterinarian.

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