reptiles

Alien snakes are bad news for island endemics

July 1, 2026 by Admin

Roger Downie, University of Glasgow and Froglife Patron

It is common for animals that first colonise isolated islands in the absence of predators to lose the defences that protected them on the mainland: a well-known example is the dodo, a species of pigeon that lost the ability to fly after many generations living predator-free on the island of Mauritius. For his reason, we need to be vigilant in avoiding the accidental introduction of predators on to islands with vulnerable endemic species. Unfortunately, we have not been careful in the past, and accidental introductions continue to occur. In this article, I discuss some examples involving snakes.

The Brown Tree Snake (Boiga irregularis) is a colubrid, native of Australia, New Guinea and the Solomon islands. It arrived by accident on the isolated Pacific island of Guam soon after World War 2. Its population remained low and localised for some years, but during the 1960s, its numbers increased rapidly and it migrated to populate the whole island. It preyed principally on birds, but also on lizards and bats. Many of the bird species had lost their defences to predators such as snakes and by the 1970s, 15 species had been lost to the island, including three endemic species and two sub-species (Wiles et al., 2003).

Brown tree snake (Boiga irregularis), By Pavel Kirillov from St.Petersburg, Russia – CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=46853510

An example recently in the news (Jones, 2026) is the Horseshoe Whip Snake (Hemorrhois hippocrepis), another colubrid, native to north-west Africa, Portugal and Spain, but not to the Balearic Islands (Ibiza, Mallorca and Menorca). In the early 2000s, this snake arrived on Ibiza, probably as eggs buried in soil attached to olive trees being shipped to the island from Spain. Since arriving, its numbers have grown very rapidly , and this population explosion has had devastating effects on the endemic Ibiza Wall Lizard (Podarcis pityusensis), formerly very abundant, but, since 2024, classed as Endangered by IUCN. The lizards are estimated to comprise about half of the snakes’ diet. Efforts are being made to cull the snake population: over 12,000 have been captured and removed since 2016.

Alarmingly, it turns out that these snakes can disperse by swimming in the sea (presumably, they did not reach Ibiza by this route earlier because the distance is too long, almost 150 km). Casbas et al.(2026) have filmed snakes swimming vigorously from Ibiza to the offshore islet of Santa Eularia, a distance of only 430 metres, and they have also collected confirmatory reports of swimming snakes observed by members of the general public. Santa Eularia is only 4.7 hectares in area, but snake traps set out there captured 58 individuals over the period September 2023 to May 2025. Surveys of the islet for wall lizards found them to be abundant as recently as 2022, but all gone by 2025. An interesting question is what motivates the snakes to set off in the sea, presumably quite a hazardous journey for a snake not normally living in an aquatic environment, and how do they detect their destination? Possibly migration is driven by competition once numbers get too high in one place, but Casbas and colleagues say that no answers are yet known to these questions.

Genetic and morphological studies of the Ibiza Wall Lizard across Ibiza, Formentera and their islets have shown there to be 30 ‘evolutionarily significant units’: this diversity is at high risk of being lost because of the snake invasion. Also lost will be the unique ecology of the islands where the lizards have major roles in pollination, seed dispersal and arthropod control.

Are there any alien snake populations in the UK? The best known is the Aesculapian Snake (Zamenis longissimus) which occurs at three British localities: near Colwyn Bay in north Wales; beside Regent’s canal in north London; and at Bridgend in south Wales. The common name of this large (140-160 cm) colubrid is derived from Asclepius, the Greek god of healing: the snakes were encouraged to live round his temples and a snake coiled around a staff became a symbol of the medical professions. The species occurs in Europe from France east to Iran, but has not been native to the UK for millennia.

Aesculapian Snake (*Zamenis longissimus*) © Matt Wilson

The Regent’s Canal population has been much studied (Langton et al., 2011; Atkins, 2020). The initial population was accidentally (or deliberately) released from a research facility near the canal in the 1980s. The snakes have bred successfully, reaching a peak population of around 40 in 2013, possibly declining a little since then.

The Colwyn Bay population derives from an escape in the 1970s from the Welsh Mountain Zoo. Successful breeding has again occurred, with an estimated population of 70 adults by 2022, all still in the Colwyn Bay area. Major et al. (2025) have reported on an extensive study of the snakes’ movements and habitat preferences. They captured 13 males and 8 females, surgically inserted radio transmitters then released the snakes at the point of capture (capture was not easy, as the snakes are hard to find: the authors estimate an average hunt of 8 hours per snake). Daily movements were on average 52 metres for males; males showed some preference for buildings as habitat, while females preferred woodland. Snakes fed on small mammals and birds, but were in turn predated by larger mammals and in one case, a buzzard. Mortality during the study was quite high, including on roads.

Unlike the Brown Tree Snake on Guam and the Horseshoe Whip Snake on Ibiza, there is no evidence that the Aesculapian Snake poses any danger to the long term survival of our native wild species, but the UK is not a small island relatively free of predators.

Click to see references

References

Atkins, W. (2020). Observations on a feral population of Aesculapian snakes. The London Naturalist 99, 77-112.

Casbas, G. et al.(2026). Swimming snakes wipe out endemic lizards from Mediterranean islets. Ecology 107, e70373.

Langton, T. et al. (2011). On the distribution, ecology and management of non-native reptiles and amphibians in the London area: 1- Distribution and predator/prey impacts. The London Naturalist 90, 83-155.

Major, T. et al. (2025). A reliance on human habitats is key to the success of an introduced predatory reptile. PLoS ONE 20 (2), e0310352.

Wiles et al. (2003). Impacts of the Brown Tree Snake: patterns of decline and species persistence in Guam’s avifauna. Conservation Biology 17, 1350-1360.

Croaking Science: Giant Tortoise Conservation: some success stories

February 1, 2026 by Admin

Roger Downie, Froglife and University of Glasgow

The Reptile Database (September, 2025) lists 366 species of turtles and tortoises (Order Testudines). According to the most recent assessment (Rhodin et al., 2018), an alarming 51.9% of these species are ‘threatened’ with extinction (i.e. are in IUCN categories Critically Endangered, Endangered or Vulnerable).

In this group, the highly terrestrial, herbivorous tortoises have evolved on isolated islands multiple times into giant long-lived species (up to 1.3 m long; 400 kg in mass; some individuals are known to have lived over 200 years). Unfortunately, several characteristics of these animals have made them highly vulnerable to human exploitation: they are slow-moving and easy to catch; often unafraid of humans because of the isolation of their habitats; they can live for months without feeding, making them very convenient as living fresh meat stores on long sea voyages in pre-refrigeration times; and their meat is highly palatable. It is estimated that the Galapagos Islands held about 250,000 giant tortoises in the 16^th century, but only 15,000 by the 1970s. This massive decline is not simply the result of over-exploitation. The Galapagos Islands lacked permanent human inhabitants until the 1830s, but once humans settled, they brought other species that competed with the tortoises; goats consumed the vegetation; black rats, which arrived earlier from visiting ships, ate the eggs and hatchlings. Even scientists contributed to the declines: the California Academy of Sciences captured 385 mainly adult specimens for museum collections in 1906.

Currently, two distinct populations of giant tortoises exist: in the Galapagos Islands and in the Seychelles, including Aldabra Atoll. Considerable efforts are now being made to conserve and enhance the extant populations of giant tortoises. There are two main motivations for this (in addition to the ethical impulse to avoid extinctions caused by people):1) giant tortoises are charismatic species which attract tourists, and therefore generate income for their island homes; 2) giant tortoises provide ecological services such as seed dispersal and vegetation control. In this article, I report on some recent conservation-related studies on both populations.

Chelonoidis, the Galapagos Giant Tortoise. The Reptile Database and Wikipedia consider this a single species with historically 15 subspecies, three of them now extinct. But some researchers (see Gray et al., 2022) describe 14 separate species, all threatened with extinction. The saddest case was ‘Lonesome George’, the last remaining individual of the Pinta Island population, who died in captivity in 2012, after a long life and many unsuccessful attempts to provide him with a suitable mate.

Evelyn Jensen (Newcastle University) has led a programme of research into the genetic make-up of the Galapagos species, using new (and rapidly developing) DNA technology to compare the genomes of extant populations with those of museum specimens collected 100 years ago or more.

The uninhabited island of Fernandino held the only population of C. phantasticus. The only sighting had been in 1906, until, surprisingly, a live ‘young’ female, named Fernanda (about 50 years old) was discovered in 2019. DNA analysis has shown that its genome is essentially the same as that of the specimen collected in 1906 (Jensen et al., 2022) and quite distinct from the other Galapagos species. The existence of this individual suggests there must have been parents fairly recently, but surveys in the challenging terrain of the island have found no evidence (it is volcanically the most active of the archipelago). The fate of Fernanda will the same as that of Lonesome George, unless other specimens are discovered.

The species on Floreana, C. niger, was reported extinct by 1840. However, it was recently found that on the largest island, Isabela, which has five distinct species of giant tortoise, each inhabiting the slopes of a different volcano, that some individuals on Wolf mountain had unusual characteristics. Again, a comparison of these individuals’ genomes with those of museum specimens showed that 89 of the Wolf population are Floreana hybrids (ships’ records show that tortoises collected on one island were sometimes released or escaped on to other islands, so a known dispersal route exists). Gray et al.(2022) have tried to sort out which of these hybrids could provide the best breeding stock for an attempted recovery of C. niger. In 2023, the NGO Island Conservation accomplished a successful eradication of the rats on Floreana, and the plan is to release on the island 300 captive-bred tortoises, genetically as close as possible to the original C.niger, in 2026.

The tiny island of Pinzon holds C. duncanensis. A small adult population exists, but they have had no breeding success for about 50 years because of rat predation on eggs and hatchlings. Since the adults are long-lived and can remain reproductively active, it has been possible to collect eggs, incubate them artificially and rear the hatchlings in captivity to a size where rats cease to be a threat (a procedure known as ‘head-starting’). This had been done successfully for decades, but, without removing the rats, it was an unsustainable strategy. Rats were eliminated in 2012 and by 2014, wild-born young were being found. Jensen and colleagues were concerned that genetic variability might have been reduced during the head-starting programme, but comparison with DNA from specimens collected in 1906 showed that no decline invariability.

Aldabrachelys gigantea, the Aldabra (and Seychelles) Giant Tortoise. Another perspective on giant tortoise conservation comes from Sheffield University where Seychellois Alessia Lavigne is studying reproductive failure in the Aldabra Giant Tortoise. This species is native to Aldabra Atoll and a number of the Seychelles islands in the Indian Ocean, with three subspecies currently extant. Evidence suggests that this population diverged from the (now extinct) Madagascar Giant Tortoise 4.5 million years ago. Aldabra Atoll lies 400 km north of Madagascar, with the Seychelles a further1000 km northeast (Aldabra is now part of the Republic of the Seychelles). Conservation has a long history on Aldabra, with Gunther at the Natural History Museum successfully campaigning for it to be declared a nature preserve. However, in the 1960s, the UK government was eyeing up Aldabra as a site for a RAF base. Julian Huxley led the opposition to this idea, with David Stoddart leading a Royal Society study of the atoll’s fauna and flora in the 1970s. The Royal Society gave way to the Seychelles Islands Foundation and, in addition to its nationally protected status, the atoll was declared a UNESCO world heritage site in 1982. The British government transferred its plans for a military base to the Chagos islands, with devasting consequences for the islanders (Sands, 2022), only recently resolved.

Anecdotal evidence suggests that there is currently very little recruitment of new individuals to the Aldabra Giant Tortoise populations, suggesting that, while the populations remain stable, this is the result of the longevity of individuals, not the health of the population. Lavigne suggests that these populations suffer from ‘extinction debt’ where the limited ability of long-lived individuals to adapt to changing environments and produce viable offspring can result in a sudden population collapse. Lavigne et al. (2025) developed a method for assessing whether unhatched turtle eggs are the result of fertilisation failure, or embryonic death at some stage or other. In a comparison of unhatched marine turtle and giant tortoise eggs, they found fertilisation failure was low in the marine turtles but much higher in their sample of Aldabran Giant Tortoise eggs. A follow-up study (Lavigne et al., 2025?) collected data on unhatched eggs from 24 clutches from six separate populations of Aldabra Giant Tortoise. Sixteen clutches showed 100% failure to hatch; the hatching success per clutch ranged from 0-91%. The Aldabra Atoll population showed 46% success, but there was 0% success in four populations. Fertilisation failure was an issue in some populations, but in most, the failure was in embryo development after fertilisation. Sample sizes were small (3-7 clutches from the different populations), but the results are nevertheless alarming. Lavigne and colleagues suggest that the underlying problem is climate change. A recent news item (Watts, 2025) reports that Lavigne has resorted to artificial incubation of a clutch of eggs (from Cousin Island, zero hatching success in the earlier study) with 13 hatchlings resulting from 18 eggs, although no details are yet available on the incubation conditions provided. Although artificial incubation is clearly not a long-term solution to the problem of reproductive failure in giant tortoises, it may provide some much-needed time for good sustainable solutions to be found.

Click to read references

Gray et al.(2022). Temporal monitoring of the Floreana Island Galapagos Giant Tortoise captive breeding programme. Integrative and Comparative Biology 62, 1864-1871.

Jensen et al. (2022). The Galapagos Giant Tortoise C. phantasticus is not extinct. Communications Biology 5, 546.

Lavigne et al. (2025). Understanding early reproductive failure in turtles and tortoises. Animal Conservation 28, 353-364.

Lavigne et al.(2025?). The illusion of stability in long-lived species: poor early-life survival threatens the persistence of Giant Aldabra tortoise populations. (published on-line)

Rhodin et al. (2018). Global conservation status of turtles and tortoises (Order Testudines). Chelonian Conservation and Biology 17, 135-161.

Sands, P. (2022). The last colony: a tale of exile, justice and Britain’s colonial legacy. Weidenfeld and Nicolson, London.

Watts, J. (2025). Thirteen rare giant tortoises hatch thanks to artificial incubation trial. The Guardian 11^th October, 2025.

British Reptile Home Ranges

December 1, 2025 by Admin

Written by Noel Ellis, Green Talent Placement

The area in which an animal stays for most of their daily activity is known as their home range. Often (though not always), this is the same as their territory, the area which they mark out and defend from unwanted intruders (O’Donnell and delBarco-Trillo, 2020; Crane et al., 2021). Reptiles cannot fly between different habitats like birds, and unlike mammals primarily travel while the sun is up. Still, reptiles can maintain home ranges and move impressive distances (Crane et al., 2021).

Heathland provides lots of small habitat spaces to support reptiles

The size of reptile home ranges can vary drastically depending on the population density, habitat characteristics, availability of food and many other factors (Day, 2012; O’Donnell and delBarco-Trillo, 2020). Additionally, British reptiles all overwinter or brumate during the colder months, staying in one area to conserve energy. In the spring and summer, some species move large distances to breeding, feeding or nesting areas depending on their life stage and current condition (Reading and Jofré, 2009).

The three native lizard species in Britain have home ranges that have been studied and recorded in certain environments.

Common Lizard – typically between 0.05 and 0.1 hectares, with males sometimes up to 0.15 ha (Day, 2012). Males are also territorial in their early spring breeding season, defending their home ranges from other males.

Slow Worm – normally around 0.02 hectares, but can be as low as 50m²(0.005 ha) (Smith, 1990). Many individuals often overlap in a single range, even in the late spring breeding season where males compete for mates, there do not seem to be clear territories (Smith, 1990; Hubble and Hurst, 2006).

Many slow worms are often found in a single area

Sand Lizard – between 0.05 and 0.2 hectares, with males having large ranges more often. Sand lizard home ranges in Britain also overlap between individuals, as larger areas cannot be effectively defended by a single lizard (Nicholson and Spellerberg, 1989).

In comparison, the three native snake species in Britain have fairly large home ranges, and have proven to be more difficult to effectively pin down scientifically.

Grass Snake – their range depends heavily on the habitat, but often falls between 20 and 40 hectares (Cathrine, 2016). Males move more often in the spring mating season, and females more often in the early summer to lay eggs, however both sexes can travel hundreds of metres daily, and often change home ranges each year (Reading and Jofré, 2009).

Grass snake swimming along stream, where they can move long distances

Adder – not well studied in the U.K., but generally small at between 0.05 and 0.5 hectares (Nash and Griffiths, 2018). They are able to move several metres per day, particularly when placed in a new environment, and when moving to and from their overwinter sites (Andersson, 2003; Nash and Griffiths, 2018).

Smooth Snake – around 0.3-0.5 hectares for juveniles, 1 hectare for adult females and 1.85 hectares for adult males. Males move around more often and greater distances than females in the breeding season of early spring, and in the late summer as they return to their overwinter spots (Reading, 2012).

And of course Leatherback Sea Turtles travel thousands of miles in the open ocean, moving between tropical nesting areas, and temperate or even polar regions to feed (Houghton et al., 2006).

Even as we continue to learn about the movement of our reptile species, key to effective conservation is giving animals the space and suitable habitat to move and change location and range if they need to. Juvenile animals, including reptiles often make risky journeys to find and establish their own home range, and can die in large numbers if routes are not available (Andrews, Langen and Struijk, 2015).

Creating wildlife corridors and plus removing harsh movement barriers can ensure that lizards and snakes can find the resources and conditions they need to survive, no matter how big or small that area ends up being (Turner et al., 2023).

Wildlife tunnel that reptiles and many other species can use

Click here for references

Andersson, S. (2003) ‘Hibernation, habitat and seasonal activity in the adder, Vipera berus, north of the Arctic Circle in Sweden’, Amphibia-Reptilia, 24(4), pp. 449–457.

Andrews, K.M., Langen, T.A. and Struijk, R.P.J.H. (2015) ‘Reptiles: Overlooked but Often at Risk from Roads’, in R. Van Der Ree, D.J. Smith, and C. Grilo (eds) Handbook of Road Ecology. 1st edn. Wiley, pp. 271–280. Available at: https://doi.org/10.1002/9781118568170.ch32.

Cathrine, C. (2016) ‘Grass snake’, in, pp. 144–157.

Crane, M. et al. (2021) ‘Lots of movement, little progress: a review of reptile home range literature’, PeerJ, 9, p. e11742. Available at: https://doi.org/10.7717/peerj.11742.

Day, C. (2012) Zootoca vivipara (Viviparous Lizard) | INFORMATION | Animal Diversity Web. Available at: https://animaldiversity.org/accounts/Zootoca_vivipara/ (Accessed: 13 November 2025).

Houghton, J.D.R. et al. (2006) ‘Jellyfish Aggregations and Leatherback Turtle Foraging Patterns in a Temperate Coastal Environment’, Ecology, 87(8), pp. 1967–1972. Available at: https://doi.org/10.1890/0012-9658(2006)87%255B1967:JAALTF%255D2.0.CO;2.

Hubble, D. and Hurst, D. (2006) ‘Population structure and translocation of the Slow-worm, Anguis fragilis L’, Herpetological Bulletin, 97, pp. 8–13.

Nash, D.J. and Griffiths, R.A. (2018) ‘Ranging behaviour of adders (Vipera berus) translocated from a development site’, Herpetological Journal, 28(4), pp. 155–159.

Nicholson, A. and Spellerberg, I.F. (1989) ‘Activity and home range of the lizard Lacerta agilis L’, Herpetological Journal, 1(08), pp. 362–365.

O’Donnell, K. and delBarco-Trillo, J. (2020) ‘Changes in the home range sizes of terrestrial vertebrates in response to urban disturbance: a meta-analysis’, Journal of Urban Ecology, 6(1), p. juaa014. Available at: https://doi.org/10.1093/jue/juaa014.

Reading, C. (2012) ‘Ranging behaviour and home range size of smooth snake inhabiting lowland heath in southern England.’, Herpetological Journal, 22, pp. 241–247.

Reading, C. and Jofré, G. (2009) ‘Habitat selection and range size of grass snakes Natrix natrix in an agricultural landscape in southern England’, Amphibia-Reptilia, 30(3), pp. 379–388. Available at: https://doi.org/10.1163/156853809788795164.

Smith, N.D. (1990) The ecology of the slow-worm (Anguis fragilis L.) in southern England. PhD Thesis. University of Southampton.

Turner, R.K. et al. (2023) ‘Diversity, fragmentation, and connectivity across the UK amphibian and reptile data management landscape’, Biodiversity and Conservation, 32(1), pp. 37–64. Available at: https://doi.org/10.1007/s10531-022-02502-w.

Reptiles and Amphibians in Winter: #WinterWildGardening

November 18, 2025 by Admin

Winter is traditionally a quieter time in the garden, but this is in fact the busiest time of year for habitat management for reptiles and amphibians. As the temperature drops, these animals become dormant, making it safer to clear out ponds and build shelters causing as little disturbance as possible.

For our winter campaign #WinterWildGardening, we have put together some tips and tricks on how you can make our species lives a little bit easier in your gardens and green spaces.

How to tackle icy ponds:

If you have a garden pond, the colder weather can cause it to freeze. The best thing to do is to periodically sweep away any snow so that sunlight can reach your pond plants and produce oxygen. This will help to prevent ‘Winterkill’ which is caused by toxic gases released in the pond (through natural decomposition of dead leaves) and not being able to escape, causing the water to become deoxygenated.

Melting a hole in the ice won’t necessarily affect the amount of oxygen diffusing into the water, but there is no harm in playing it safe! You can gently melt any ice with a cup or pan full of hot water to allow more active animals like newts to move to the surface to breathe.

You can also try floating a small object, e.g., a tennis ball, in the water or keep your fountain going (if you have one) to prevent ice formation.

If you have frog spawn, the upper portions may freeze, but the spawn that is underwater should survive. However, if you have a very small pond and/or it is shallow and prone to freezing throughout, you can temporarily place your frog spawn into a bucket of pond water and place in a garage, or similar place, out of the freezing conditions.

Remember that moving spawn to other ponds risks spreading disease, so once the cold weather has passed, ensure that you return the spawn to the same pond to allow it to continue to develop.

Creating overwintering sites:

Something as simple as a pile of leaves or areas of dense vegetation and scrub close to your garden pond will provide areas for amphibians to take refuge during periods of cold weather.

Log piles and rockeries are another simple idea to provide our species with somewhere to see out the winter months. As well as providing cover from adverse weather, dead wood attracts insects on which reptiles and amphibians will feed.

If you want to go further, you can build a hibernaculum. You can find instructions on how to do this here.

If you don’t have space to create a hibernaculum, you could consider a toad home. These can be made simply by upturning a plant pot and knocking a hole in the side for a door. Place old leaves or grass inside your toad home for extra protection. You can find instructions on how to build one here.

What to do if you disturb a reptile or amphibian during winter:

Reptiles and amphibians lie dormant during the coldest months but will take advantage of milder patches of weather to come out and forage. For this reason, if you do disturb an animal in winter, it should be unharmed if covered up and left undisturbed.

If you are unable to put the animal back where you found it, place it somewhere that offers protection from frost and predators like cats and birds, for example, log piles, under a shed or within your compost heap. It should not be somewhere ‘warm’, just a place that is frost free.

If you spot any of our species out and about, please remember to record them on our free Dragon Finder App. Data from the Dragon Finder App is crucial going forward to monitor the relationship between temperature changes and the behaviours of reptiles and amphibians in the UK.

If you spot any sick or injured reptiles or amphibians, please report them to our partners at the Garden Wildlife Health project.

Further Resources:

For more information on how you can help reptiles and amphibians during winter, check out….

Pond Maintenance
How-to guides (hibernaculum, toad homes etc.)
Frequently Asked Questions

Amphibians and reptiles in the sky

October 7, 2025 by Admin

Written by Andrew Smart, Head of Science & Research

While planning for a dark sky watch to catch the Draconid meteor shower between 6–10 October, I came across a constellation I hadn’t been aware of previously; Lacerta, the lizard.

Lacerta is one of the recognised 88 constellations but was added in 1687 and so there are no linked Greek myths like many of the original constellations. The brightest stars form a small ‘W’ and its sometimes referred to as ‘little Cassiopeia’ which is what I’d always known it as. This first diagram is the original drawing by Johannes Hevelius in his listing in 1687, when he originally called the constellation ‘Stellio’ , now the species name for the started agama (Stellagama stellio). A second, and more recent, interpretation includes the ‘head stars’.

https://historiasdeastronomia.es/vistas/images/artistic/lacerta.jpg

https://bathastronomers.org.uk/wp-content/uploads/2016/12/lac_constellation_artwork.jpg

https://theskylive.com/sky/constellations/lacerta-constellation

To find Lacerta, locate the “W” shape of Cassiopea in the northern UK sky. Lacerta lies to the south of Cassiopea and to the west of the distinctive shape of Cygnus, the swan. It also appears that early Chinese astronomers included the same constellation stars within a ‘flying serpent’.

Other reptilian constellations include: Serpens, Draco and Hydra, all ‘original’ constellations catalogued by the Greeks.

Serpens represents a giant snake held by the healer Asclepius (see ‘Why Aesculapian?’ blog). The snake is found in two sections, Serpens caput (the head) and Serpens cauda (the tail), held by Ophiuchus (another name for Aesculapius).

Draco the dragon is a large constellation in the northern sky and is circumpolar, coiling around the Plough as shown here in Urania’s Mirror (constellation cards published in London in 1825). Draco was meant to be the dragon slain by Hercules when it guarded the golden apples of the Hesperides and is famous for being the source of the early October Draconid meteor shower linked to the passage of a periodic comet.

Hydra, represents the Greek myth of a multiheaded half woman – half serpent. Hydra is the largest constellation and stretches across the southern sky.

Two other reptiles are present in the southern sky:

Hydrus, the water serpent, devised by the Dutch astronomer Petrus Plancius in 1597 is reputed to represent the sea snakes seen on their southern voyages by Dutch sailors.

Chameleo (the chameleon) is another small southern constellation, also created by the Dutch astronomer Petrus Plancius in the 16th century after observations by the Dutch navigators Pieter Dirkszoon Keyser and Frederick de Houtman.

One other ‘non-accepted’ constellation worthy of mention is Bufo, the toad, first proposed by John Hill in 1754 in ‘Urania’ his book of astronomic charts. Bufo was one of 15 ‘new’ constellations Hill proposed. Bufo is situated between Libra and Hydra in the southern hemisphere but is not widely recognised as a constellation.

Since writing this I’ve become aware of more information relating to Chinese, First Nation, Native American, Mayan and Aztec mythology and astronomy linked to reptiles and amphibians so watch this space….and next time you gaze up at the night sky (maybe taking a pause on a Toad Patrol) or watching the Leonid meteor shower; 6 – 30 November (peak 17/18 November), take a moment and see if you can find a lizard, a dragon or a snake!

What our animals are doing this month

October 1, 2025 by Admin

Common Lizards in October

As the crisp days of October arrive in the UK, our native common lizard (Zootoca vivipara) enters one of the most important stages of its year: preparing for brumation (similar to hibernation, but animals will only come out during warmer periods in winter). These reptiles, often spotted basking in summer sunshine, are now shifting their behaviour to cope with falling temperatures and shorter days.

common lizard

Seasonal Behaviour

Reduced Activity: Being cold-blooded, lizards depend on external warmth to stay active. By October, the cooler air and weaker sunlight mean they spend far less time basking and feeding.
Searching for Shelter: Instead of roaming in search of prey, they begin looking for hibernation sites, known as hibernacula, where they will remain hidden until spring.

Choosing a Brumation Spot

Common lizards seek out safe places that provide:

Frost Protection – deep vegetation, old tree stumps, or burrows that stay above freezing.
Moisture – enough dampness to prevent dehydration, but not waterlogged.
Cover from Predators – hidden crevices or log piles that conceal them from birds, mammals, or even domestic pets.

These shelters are vital to survival, as a poorly chosen site could leave the lizard vulnerable during the long winter. Find out more about how to build shelters for wildlife at home on our website.

Young Lizards in October

Juveniles, born in late summer, face an especially tough challenge. They have only a few weeks to feed and build strength before cold weather forces them underground. October is a critical month in their development, and only those that find secure hibernation spots are likely to emerge again in spring.

Spotting Lizards in Autumn

While sightings are less common, it is still possible to see lizards on mild October days. They may bask briefly in weak sunshine to top up their body heat before returning to cover. By the end of the month, however, most will have vanished from view completely.

If you spot dead (make sure they’re dead and not hibernating during the winter months) or diseased reptiles or amphibians, please report them to our partners at Garden Wildlife Health.

Remember to record any sightings on our free Dragon Finder app. This helps us see how reptiles are fairing in the UK. Reptiles are vastly under-reported!

How You Can Help

If you manage a garden or local green space, you can make conditions friendlier for common lizards by:

Leaving log or rock piles undisturbed.
Avoiding cutting back dense vegetation in autumn.
Creating wild corners where lizards can hunt and later hibernate.

These simple actions can provide vital refuges for reptiles as they prepare for the cold months.

In Summary

By October, common lizards are winding down their year, seeking safe winter homes where they will remain in torpor until spring sunshine returns. For wildlife watchers, this is the last chance to spot them before their seasonal disappearance and a reminder of just how carefully adapted they are to Britain’s changing seasons.