Large Lizard

PRE-OWNERSHIP ASSESSMENT and GUIDANCE

This comprehensive guide aims to provide prospective owners and businesses with essential information regarding the responsible ownership of large lizard species. Our commitment to promoting responsible reptile ownership is reflected in the thorough education and preparation of potential owners.

This large species policy has been created to align REPTA and member businesses with government expectations for companion animal sectors as a means of selfregulation. Through self-regulation REPTA can show that the reptile industry is proactively addressing the potential issues, thereby limiting the undue influence of radical animal-rights campaigns.

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What is a large lizard?

This guide references large lizards from the family Varanidae where any species of either sex may meet or exceed 60cm snout-to-vent length (SVL). The total body length (TL) of these species will be greatly inexcess of this.

Species within scope listed by family

White Throat Monitor (Varanus albigularis albigularis) 110cm–150cm (35–65cm SVL)
Black Throat Monitor (Varanus albigularis microstictus) 110cm–150cm (35–65cm SVL)
Nile Monitor (Varanus niloticus) 150cm–200cm (40–70cm SVL)
Ornate Monitor (Varanus ornata) 150cm–200cm (40–70cm SVL)
Lace Monitor (Varanus salvator) 150–200cm (50–65cm SVL)
Asian Water Monitor (Varanus salvator) 150cm–240cm (50–80cm SVL) (and closely related monitors, previously sub-species of salvator)
- macromaculatus
- bivittatus
- salvator
Crocodile Monitor (Varanus salvadorii) 180cm–280cm (55–80cm SVL)
Perentie (Varanus giganteus) 150–250cm (55–90cm SVL)

Rationale for REPTA’s guidance

Large lizard species are actively and successfully maintained as companion animals within the UK. Because of the potential future financial, spatial and energy consumption factors involved in large lizard management, REPTA considers the thorough education and preparation of potential owners to be of great importance as part of our commitment to responsible reptile ownership.

REPTA understands that reptile owners never purchase an animal with the intention to relinquish ownership of their companion animals, but the species within scope here have potentially demanding requirements which are at risk of being underestimated by new owners. However, the rehoming network for reptiles is underdeveloped, and the lack of support from national animal welfare charities means that rehoming options for large lizards is severely limited.

REPTA would therefore encourage all responsible companion-animal selling businesses to exercise a thorough pre-ownership assessment. Such an assessment will flag issues regarding potential future spatial requirements and include considerations for energy consumption. Business owner’s duty of care Ownership of any companion animal is a considerable commitment and the potential owner should be prepared to thoroughly research a potential new species. Companion animal selling businesses should also take seriously their responsibility to provide prepared and competent homes for any animal leaving their care. REPTA has included supporting information for specialist companion animal selling businesses to refer to while completing the assessment process. Should businesses selling large lizards require further clarity regarding the assessment process or the supporting information they can contact REPTA at any time.

Business owner’s duty of care

Ownership of any companion animal is a considerable commitment and the potential owner should be prepared to thoroughly research a potential new species. Companion animal selling businesses should also take seriously theirresponsibility to provide prepared and competent homes for any animal leaving their care.

REPTA has included supporting information forvspecialist companion animal selling businesses to refer to while completing the assessment process. Should businesses selling large lizards require further clarity regarding the assessment process or the supporting information they can contact REPTA at any time.

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large Lizard management

SUPPORTING INFORMATION

1.0 Spatial considerations

Spatial considerations will be a primary focus when considering large lizard management. Most will purchase their animal when neonate or juvenile in size, when their spatial requirements are much like any other reptile and spatial provision is not an issue. As a large species grows, so does its spatial requirement.

To be able to formulate guidance regarding spatial requirements of large lizards, REPTA has used a document prepared by the Federation of British Herpetologists:

FBH Code of Practice for recommended minimum enclosures sizes for reptiles
A copy of this document can be found at www.thefbh.org.

The code of practice was ratified by multiple stakeholder organisations including:

BZVS – British Veterinary Zoological Society

CASC – Companion Animal Sector Council

BSAVA – British Small Animal Veterinary Society

As well as a raft of regional and national reptile-owner societies and groups.

1.0 Spatial considerations

To be able to formulate guidance regarding spatial requirements of large lizards, REPTA has used a document prepared by the Federation of British Herpetologists:

FBH Code of Practice for recommended minimum enclosures sizes for reptiles
A copy of this document can be found at www.thefbh.org.

Because the code of practice was ratified by multiple stakeholder organisations including:

BZVS – British Veterinary Zoological Society • CASC – Companion Animal Sector Council
BSAVA – British Small Animal Veterinary Society As well as a raft of regional and national reptile-owner societies and groups.

1.1 Enclosure sizes

The FBH code of practice uses the lizards snout-to-vent length (SVL) to recommend enclosure standards for all lizard species.

Vivarium length: x6 SVL
Vivarium depth: x0.3 SVL
Vivarium height: x3 SVL

For example, a lizard with an SVL of 50cm would require a vivarium with recommended dimensions of 300cm x 150cm x 150cm (length x depth x height)

A table illustrating SVLs and the recommended enclosure dimensions is included on the preownership assessment form and companion animal selling businesses should highlight or circle the assumed appropriate enclosure size for the species being purchased.

1.2 How this relates to the family home

The information contained in the supporting information section pertains only to adult large lizards. Using the previous example of an adult lizard with an SVL of 50cm will mean the recommended adult enclosure size is 300cm in length (10ft) and 150cm in depth (5ft). This is a considerable amount of floor space.

Due consideration must be given to placement within the home. If purchasing a baby or juvenile lizard, due care must be taken to ensure an adult enclosure of

1.3 Space availability long term

Consideration of the future and changes that may take place in the family home is paramount. Is your current employment secure? Is there any chance that you may have to downsize or modify your living arrangements? Is your family still growing and the space allotted for the adult lizard could potentially be needed for the arrival of new family members? If there is the potential for such an occurrence is there available space outside for an ex-situ enclosure within a shed or summerhouse? If there is the reasonable potential for such situations to arise and there is not the availability of ex-situ space a potential owner should consider if they can provide for the long term management of a large lizard.

1.4 Custom enclosure construction

If an enclosure is to be constructed within the home for an adult large lizard, due consideration must be given to how this is to be achieved. Custom commercial vivarium building companies generally only produce enclosures with maximum dimensions of 244cm x 120cm x 120cm. Commercially available boards commonly used in the construction of vivaria (including melamine or Conti-Plas™, plywood and OSB) generally have maximum dimensions of 244cm x 120cm. The enclosure required for large lizard species could be considerably larger than this. Does the potential large lizard owner have the required skills to construct a suitable enclosure or the resources to outsource this to a skilled tradesman? Care must be taken to ensure joints between boards are sealed correctly to maintain security of the enclosure and to limit soiling of the household, including water ingress to floorboards and house structures.

1.5 Ex-situ management

Ex-situ housing arrangements for adult large lizards is worthy of consideration as it will not impinge on available space within the family home. There will be two types of ex-situ accommodation for large lizards. This will often mean using an outbuilding or garage which is a permanent structure which would mean foregoing using such outbuildings for storage or parking a car in the garage. Is the potential large lizard owner willing to make such a sacrifice?

Another option would be to construct a nonpermanent structure such as a shed or summerhouse to house a specimen. There are many solutions on the market which could be used for such a project, but they could come at great expense. These types of building are totally un-insulated and will require considerable work to make them energy efficient.

1.6 Power supply

Ex-situ enclosures without a pre-existing ring main will need to have power fed to it. Given the volume of the enclosure the power required to adequately heat it could be considerable. This may require a separate ring main to be installed with its own breaker on the fuse box to avoid tripping and overloading an existing ring main. This may include digging a gully through gardens or flower beds to achieve this.

1.7 Emergency power-outage plans

Of particular pertinence in winter, what happens if there is a power outage? There may need to be an alarm on the circuit to alert the potential owner of power supply problems. What contingencies are there for temporary housing in such a situation?

1.8 Security of enclosures

Large lizards are powerful animals and can create considerable force with which to test doors and vents. Care must be taken, particularly with ex-situ enclosures, to ensure access points and ventilation are escape proof and cannot be pushed open. Sliding glass or access doors should remain locked at all times to prevent accidental escape.

1.9 Safely entering the enclosure

Assessment of a large lizard’s position prior to entry is essential. In traditional vivarium this is not a problem because sliding glass doors serve as both a viewing panel and an access route. In ex-situ or whole room enclosure solutions the traditional wooden panel door should be replaced with an uPVC window door such as used in conservatories.

1.10 Water

Some large lizard species will require large water containers as some species will bathe if given the opportunity. Given the volume of water that may be required, a plan must be in place to efficiently refresh the water when it becomes soiled. This may involve plumbing in such a water feature, if only to drain it away. Alternatively an external canister filter could be used to circulate and filter the water. All pipe work and any such filters should be protected from exploration by the lizard. The use of hosepipes may be more appropriate when it comes to refilling the water container for large lizards rather than potentially walking through the house with multiple buckets of clean (or soiled) water.

1.11 Enrichment and climbing

Large lizards have all the same needs as other companion lizard species. Enclosures regardless of size should provide hiding opportunities, foliage for cover and exploration, as well as climbing apparatus. Any such equipment must be robust enough to support heavy-bodied lizards.

1.12 Substrates

As a continuation of enrichment, thought must be given to the volume of substrate required to adequately fill a large enclosure. This will need to be changed regularly as large lizards can produce prodigious amounts of urates and faecal material. Therefore the floor should ideally be waterproof to prevent seepage and bad smells becoming a feature.

2.0 Energy consumption

Potential large-lizard owners must appreciate the energy consumption implications of enclosures. All large lizards hail from desert, tropical or sub-tropical regions. Some lizards will have a gentle gradient spread across the length of the enclosure, while others will have incredibly high basking temperatures. Regardless of the length and depth of an enclosure, heat may need to be provided even at the cool end of the closure.

There is much nuance in gradient types based on origin of large lizards. As a result it is difficult to pigeonhole lizards into certain groups. Much research will be required by the potential owner to ensure the thermal gradient is appropriate for the species kept.

Desert/semi-desert/scrub and savannah species may require basking temperatures approaching or in excess of 50 Celsius with a noticeable drop to cooler temperatures throughout the remainder of the enclosure without dropping below 25 Celsius. In these enclosure types heating may be grouped towards one end of the enclosure.

Tropical/sub-tropical/grassland species may require basking temperatures approaching 35–40 Celsius with a gentle drop throughout the remainder of the enclosure without dropping below 25 Celsius. In these enclosure types heating may need to be spread throughout the length of the enclosure.

Below is a case study of prices based on domestic energy pricing from 2010–2023 using 400W per hour over a 24-hour period and 1500W (1kWh) over the same period. Prices shown are per year (annum).

using 400W per hour

YEAR	ENERGY PRICE	COST
2010	13.8p/ kWh	£482.22
2013	17.9p/ kWh	£629.50
2017	18.5p/ kWh	£646.46
2020	22.0p/ kWh	£768.76
2023	34.0p/ kWh	£1,188.09

using 1500W per hour

YEAR	ENERGY PRICE	COST
2010	13.8p/ kWh	£1,808.35
2013	17.9p/ kWh	£2,345.61
2017	18.5p/ kWh	£2,424.24
2020	22.0p/ kWh	£2,882.88
2023	34.0p/ kWh	£4,455.36

Problems can arise when prudent planning has failed to take place; this is usually at the juncture where a maturing animal moves to an adult enclosure from the juvenile one. The power requirement to heat the greater volume to the same required temperatures can be considerably more.

2.1 Heating

In adult large lizard enclosures, multiple heat sources may be required.

To adequately heat the volume of air within the enclosure to the recommended levels.
To provide a basking area or heat island large enough for the entire lizard bask beneath. This will mean multiple, high power rated fittings, associated domes and guards, and thermostatic control.
Dependent upon the length of the enclosure, there may need to be further staggered loweroutput heaters (or heaters on a separate thermostat) towards the cool end of the enclosure to prevent the temperature falling below recommended levels.

2.2 Lighting

Lighting large enclosures is important for the enrichment of the species kept within. The issue here is that UVB radiation diminishes over distance. Therefore, given the height specifications recommended, this could mean multiple UVB sources being required to raise the basking area to the required level. The recommended UVI range for large lizards is variable depending upon natural habitat. The UVI should range across the enclosure from 0.0 at the cool end to 3, 4 or even 5 at the basking area.

With the key being to drive UVB down onto the basking area, the use of high output bulbs such as mercury vapour lamps may be beneficial as they will outperform the distances achieved by conventional UV tubes.

Full spectrum lighting, or those replicating daylight, are recommended for replicating a large lizard’s circadian rhythm. These will certainly be needed if real plants, bushes or trees are used within the enclosure.

Enclosures should ideally have a lighting (photo) gradient much the same as the thermal gradient. This will effectively provide a bright end and a dark end in the enclosure. Lighting should be concentrated around the heat sources. UVB radiation can only be absorbed by way of heat, so thermal and photo output should not be mismatched.

2.3 Insulation

Of particular importance in ex-situ enclosures, insulation will be essential to mitigate heat loss, create an even thermal gradient and limit power consumption. Power consumption could easily become unmanageable without considerable insulation to preserve the energy.

3.0 Financial implications

During the neonate and juvenile stages of a large lizard’s lifecycle, their potential costs from a spatial and energy consumption perspective remain much the same as any modest size lizard. However, as these species attain lengths of 120cm or more within 2–4 years, spatial sacrifice and considerably increased energy consumption can be expected.

Any potential owner must consider the impact on family finances in time. At no point would it be acceptable for a potential owner to buy a large lizard species with the inclination to only keep it through the neonate and juvenile lifecycles. Companion animals are for life and any potential owner has a responsibility to thoroughly consider the future for their pets.

Specialist companion-animal selling businesses should put considerable emphasis on the changing requirements of large lizards as they grow. Any potential owner bears the total responsibility of deciding if they are capable, spatially and financially, of providing for such a species long term.

4.0 Health and safety

Regardless of the taxa, any large or powerful companion animal should undergo a risk assessment to ensure the owner exercises safe maintenance and interactions with their pet. Many large lizards become totally tame, but within the enclosure occasional territory disputes and instinctive feeding responses mean keepers should always be alert of where the lizard is and read its body language.

4.1 Entering the vivarium

The vivarium or room should have viewing panels or a glass doors so the position of the lizard within the enclosure can be assessed prior to entering. If it is nearing a regular feeding interval the lizard may be in hunting or roaming mode and be triggered by movement within the vivarium.

4.2 Distancing tools

Large lizards are often protective of their territory and this may on occasion lead to disputes as a keeper tries to work within the enclosure. Large lizards will stand their ground, if approached ‘huffing’ and inflating the chest, gaping of the mouth or tail whipping may occur. Large lizards are very powerful and tail whips can break the skin. Keepers should try to undertake maintenance away from the lizard’s immediate vicinity if this is the case. If the lizard is where a keeper wants to work (such as within its water container) it may be less stressful for the lizard if the keeper waits for it to return to the basking area.

4.3 Young people

Great care should be taken with young keepers and they should not be allowed inside the enclosure where the lizard is more likely to feel territorial. If a keeper wishes for a young family member to meet their large lizard, this should be done in an open space. Under no circumstances should young children pat or pet the head of a large lizard. Instead they should be encouraged to stroke the lizard further down the body. A young family member should never be left alone with a large lizard.

4.4 Traditional family pets

Large lizards are predators and are often opportunistic in their feeding habits. Great care should be taken to make sure any other pets cannot come too close to a large lizard. Fur, dander and smells from smaller pet mammals, such as rats, guinea pigs, rabbits and ferrets, may cause a feeding response from a large lizard. If small mammals have been petted, clean clothes should be worn and hands thoroughly washed before working with a large lizard.

4.5 Handling

Interaction with large lizards can be hugely rewarding for the keeper, while also offering enrichment for the lizard. Care must be taken when moving a lizard due to the sheer weight some species may attain. Some large specimens can weigh up to 15kg. Large lizards have sharp claws and powerful limbs for climbing and digging. These claws can easily split skin so heavy gauntlets should be used and keepers should wear thick top clothes like sweaters and coats to protect their arms and chest from scratches and cuts.

Lizards should be handled in open space where they can investigate their surroundings. Avoid areas of clutter or outside areas near trees. Lizards are expert climbers and will take to the trees for safety quicker than a keeper can react. Care must be taken with certain lizards as their pineal eye is activated when in full sunlight. This can make them easily spooked by planes or birds flying over head and make them dart for cover. Only trusted lizards should be allowed to roam outdoors and this should always be under constant supervision. Leashes and harnesses should be avoided as they can damage the collar bones of lizards.

4.6 Assistance

Safe handling and removal of large lizards from the enclosure can usually be undertaken by a single person. However, if the lizard is roaming it is often useful to have at least one other person present to help keep it within the desired area of outside space. Should a lizard become spooked or belligerent then a second keeper will become essential to return the lizard to its enclosure safely, minimising potential damage to both the keeper and lizard.

5.0 Common health issues

Some larger lizard species will be imported specimens and internal parasitic burdens may be an issue. Faecal screening should take place to establish the best course of action. This can be undertaken by a local reptile specialist veterinarian or an online screening service that will send out sample kits.

Shedding issues can arise from lizards not having adequate humidity or bathing opportunities. Thermal burns may occur because of the high temperatures required by certain species and a lack of control over heat sources. Thermostatic control is essential to avoid such occurrences.

5.1 Specialist veterinary practices

Regardless of the species being sold, companionanimal selling businesses should signpost local veterinary surgeons that are proficient and comfortable with the species being sold. As part of LAIA regulation, pet-selling businesses should be registered with a local specialist veterinarian, so this vet is the obvious choice for the prospective keeper’s requirement. In the event that the prospective owner has travelled a distance to be assessed, it is the prospective owner’s responsibility to prove they have identified a suitable and local veterinary practice.

5.2 Pet insurance options

Pet insurance should be mentioned to a prospective owner and they should understand what is and is not covered. Given the mass of large lizard species, the volume of items such as antibiotics, should they be needed, would cost considerably more than regular sized pet reptiles. It may therefore be pertinent to take out an insurance policy to help in the event of illness or injury occurring.

5.3 Microchipping

In the event of escape or theft, a microchipped large lizard can be traced to their owner. This will also dissuade keepers from wild releasing their animals should their circumstances change. Having an animal micro-chipped is a relatively low cost and causes no long-term detriment to the animal. Microchipping their animal will also demonstrate a heightened level of responsibility when voluntarily undertaken by the owner.

Other considerations

Feeding

Some large lizards will happily drop feed, which means leaving frozen-defrosted prey items to be discovered within the enclosure. Other specimens will only feed if the frozen-defrosted prey item is made to move or shake, so a method for moving the prey item is necessary. Large lizards should never be fed by hand.

Many of the species within the scope of this document also use infrared heat pits in the face to detect their prey. A keeper’s hand will register as hotter than the prey item, and this could present a target which determines where the snake decides to strike, coil and subdue prey. This is why apparatus such as litter pickers should be used to hold frozen-defrosted prey if strike feeding is the preferred method of feeding.

Feeding intervals

Reptile obesity is a frequently-seen issue in captive reptiles, because keepers are often too generous with food. The metabolic rate of large lizards slows into maturity, so the frequency of feeds should be reduced considerably. Large lizards are capable of consuming huge meals which will keep mature snake satisfied for several months.

Sourcing food

Rats, guinea pigs and rabbits will eventually be too small for large lizards as a single meal However larger prey items are not commercially available, and using multiple smaller prey items such as rabbits could become prohibitively expensive. Prospective owners may need to look at ways of sourcing larger prey items that are not commonly or commercially available.

Cohabitation

Generally, this to be avoided unless breeding trials are underway. Males of particular species can become combative and highly aggressive during the breeding season, so great care must be taken. Feeding cohabiting snakes can also be complex, creating a multitude of risks.

Two 400cm snakes fighting over a prey item is not a situation in which a companion animal owner wishes to find themselves in. For the most part, if cohabiting can be avoided then it should be, as this will make the enclosure a safer space for the keeper and the kept.

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If businesses require further clarity about the assessment process, its purpose or any other issues please email Charles Thompson, Trade Delegate at: c.thompson@repta.org or contact us here.