Decor
- Sturdy branches for climbing
- Lots of cork tunnels and hides
- Artificial plants for aesthetic cover
- Large water bowl — drinking and bathing
Monitor lizards · Care guide
Yellow Headed Water Monitor Care Guide
Varanus cumingi
Endemic to the Philippines, this species thrives in mangrove, forest and water margins. Adults average 4–5 ft. They are largely terrestrial but will climb — plan a large humid vivarium with a hot basking zone, T5 6% UVB, cork tunnels, and a large bathing bowl.
At a glance
Quick facts
Key parameters for day-to-day husbandry. Full detail is in the sections below.
-
Daytime probe
82–85 °F
28–30 °C · middle of the vivarium
-
Night drop
10 °F
6 °C below daytime
-
Humidity
60–80%
With a night spike
-
UVB
T5 6%
Ceiling-mounted tube
01 · Housing
Enclosure & housing
Endemic to the Philippines — mangrove, forest and water margins. Adults average 4–5 ft. Largely terrestrial but will climb: sturdy branches, lots of cork tunnels and hides, a high-humidity coir and orchid bark mix, and a large water bowl for drinking and bathing.
Adult minimum size
72″ W × 48″ D × 48″ H
6 ft × 4 ft × 4 ft for a single adult. Adults average 4–5 ft, so the space requirement is real.
Substrate
- Any high-humidity mix
- Coir and orchid bark mixed
Cleaning
- Daily: spot clean to keep the enclosure smelling fresh and limit bacteria
- Every 4–6 weeks: full clean if kept relatively clean — replace substrate, disinfect décor and vivarium, then return clean, dry décor
Housing diagram
Enclosure example
Front view 72″ wide × 48″ tall (depth 48″) · sturdy branches · cork tunnels · large bathing bowl
- Front proportions — 72″ wide × 48″ tall (3:2); depth 48″ — 6 × 4 × 4 ft
- Branches — sturdy climbing (largely terrestrial, will climb)
- Cork — lots of tunnels and hides
- Water bowl — large, for drinking and bathing
- Substrate — high-humidity coir and orchid bark mix
- Heat & UV — hot basking zone · T5 6% on the ceiling
Setup diagram · 1 of 2
Top-down view
Heat bulb & probe left–right positions · Recommended temps need this layout
Setup diagram · 2 of 2
Front view
Looking into the vivarium · bulb on the ceiling · probe hangs down the back
- Heat bulb — about one-quarter from one side, halfway front to back (on / through the ceiling)
- Probe — one-quarter from the opposite side, hanging down the back about halfway down
02 · Climate
Temperature & UVB
A hot basking zone, a clear gradient, T5 6% UVB, and humidity of 60–80% with a night spike.
Daytime temperature gradient
When the heat bulb and thermostat sensor are placed as instructed, a probe target of 82–85 °F (28–30 °C) creates this spread. The probe point is not the basking spot.
| Zone | Temperature |
|---|---|
| Cool side | 78–80 °F (26–27 °C) |
| Probe point (thermostat probe target) | 82–85 °F (28–30 °C) |
| Warm side | 100–110 °F (37–43 °C) |
| Basking spot (hottest point under bulb) | 125–135 °F (50–57 °C) |
| Night drop | Reduce thermostat by 10 °F (6 °C) drop |
Photoperiod & night
- Winter: about 12 hours light/heat
- Summer: up to 16 hours when days are longer
- Night: drop temperatures by 10 °F (6 °C)
- Clear day/night temperatures let metabolism slow — essential for rest
UVB lighting
- Recommended T5 unit with 6% UV output on the ceiling
- Mount straight across or diagonally (diagonal often places the power unit toward a rear vent)
- Replace every 12 months — UV output degrades over time
- Match UV on/off to heat schedule (morning on, evening off)
- UVA boosts appetite & activity; UVB enables vitamin D3 / calcium absorption
Humidity & water
Yellow Headed Water Monitors need a humid tropical setup. Keep 60–80% humidity by spraying twice a day, with a heavier spray in the evening to create the nighttime spike. A large cool-side water bowl is for drinking and bathing, and also helps hold humidity. Use a high-humidity mix of coir and orchid bark.
Day
60–80%
Ambient humidity
Night
Spike
Heavier spray · overnight rise
- Heavier evening spray to raise humidity a little toward the top of the 60–80% range overnight
- Large cool-side water bowl — drinking, bathing, and humidity support
- Always use de-chlorinated water like Reptishield, never untreated tap water.
Climate diagram
Lighting setup
T5 6% UVB on the ceiling · heat on the warm / basking side
- T5 6% UV unit — ceiling-mounted (straight or diagonal); UVA supports appetite & activity; UVB enables vitamin D3 / calcium absorption
- Heat dome — warm side; basking 125–135 °F (50–57 °C); same on/off routine as UV (morning on, evening off)
- Photoperiod — 12 hours in winter, up to 16 hours in summer
- Replace UV every 12 months — output degrades even if the tube still glows
First power-up tip
Always have the thermostat dial turned down before you plug it into the mains for the first time.
03 · Nutrition
Diet & feeding
Insect-led diet with optional plant matter. Dust every feed, gut-load insects well, and use the method of 5 while settling. In the wild they also take birds, fishes, mammals, eggs and carrion.
At a glance
Feeding cheat sheet
- Type
- Insects · plant matter if accepted
- Settling
- Method of 5 — feed 5 insects at a time
- Settled
- Often 10–20+ crickets daily · adults may need 1–2 food-free days/week
- Dust
- Every feeding · 4:1 calcium : Nutrobal
- Water
- Large cool-side bowl · Reptisafe or bottled · drinking, bathing and humidity
Staple insects
Feed regularly · dust every feed
- Crickets, locusts, Dubia roaches
- Calci worms
- Vegetables if accepted (most will not eat them)
Occasional & meat
In moderation · great meat eaters
- Wax worms, mealworms, Morios
- Mice, chicks, small amounts of cat food
- Whole fish and eggs
Supplements — every feeding
Dust every feeding — live foods and salads — with a 4:1 mix of calcium : Nutrobal (4 parts calcium to 1 part Nutrobal). Mix first, then coat the food every time you feed.
Settling appetite — method of 5
New Yellow Headed Water Monitors are often stressed and may not eat well for the first few days. This is perfectly normal. Until you know their habits, use the method of 5: offer five insects at a time and wait until they are eaten before adding more. That reduces leftover insects that can stress or injure the animal. Once settled, 10–20+ crickets daily is relatively common; adults often need one or two food-free days each week.
Feeding style
- Hunting and chasing food provide exercise and enrichment
- Hand feeding can help bonding — excessive hand feeding can lead to obesity
- Great meat eaters — mice, chicks, small amounts of cat food, whole fish and eggs
Water
- Large cool-side bowl — drinking, bathing, and humidity
- Reptisafe or bottled water only — never untreated tap
Gut-load insects before offering — variety matters for calcium-to-phosphorus (Ca:P) and vitamins.
Why gut loading matters
Feeder insects must be well fed before offering. In the wild, lizards eat insects that themselves ate a wide variety of foods — providing complete nutrition and a better calcium-to-phosphorus (Ca:P) ratio.
- Use commercial gut-load foods with quality ingredients
- Add fresh reptile-safe vegetables for variety
- A single piece of carrot or potato is not enough — poor Ca:P and limited vitamins/minerals
Speak to a member of staff for more feeding advice.
04 · Behaviour
Handling & behaviour
Very active monitors (about 4–5 ft). Largely terrestrial but will climb. Settling and regular feeding come before handling.
- Step 1
Settle first
Allow the Yellow Headed Water Monitor to settle and begin eating regularly before handling — we recommend at least two successful feeds first. Adapting is stressful; early handling can make it worse.
- Step 2
Short sessions
Initial sessions: 5–10 minutes only. Lengthen as the monitor becomes more comfortable.
- Hygiene
Wash hands
Always wash or disinfect hands before and after handling to prevent bacteria transfer both ways.
- Warning
No aerosols
Do not use aerosols or plug-in air fresheners near the enclosure — the chemicals can harm your Yellow Headed Water Monitor.
05 · Welfare
Health & welfare
Prevention starts with correct husbandry — heat, UVB, hydration, and supplementation working together.
Best prevention: good husbandry
Correct temperatures, supplementation, hydration, and UVB keep the immune system and gut working well — supporting essential physiological processes.
Inert substrates Paper, lino, carpet — pros & cons
Pros
- Lower impaction risk
Cons
- Limit natural behaviours such as digging
- Can increase faecal contamination (waste less absorbed)
Questions
FAQ
What size vivarium does a Yellow Headed Water Monitor need?
For a single adult, a minimum of 6 ft × 4 ft × 4 ft (72″ wide × 48″ deep × 48″ tall). Adults average 4–5 ft. They are largely terrestrial but will climb, so provide sturdy branches plus lots of cork tunnels and hides, artificial plants for cover, a high-humidity coir and orchid bark mix, and a large water bowl for drinking and bathing.
What temperatures does a Yellow Headed Water Monitor need?
Set the thermostat probe to 82–85 °F (28–30 °C) by day with the heat bulb about one-quarter from one side and the probe one-quarter from the opposite side, hanging down the back about halfway down. That creates a gradient of 78–80 °F on the cool side, 100–110 °F on the warm side, and a basking spot of 125–135 °F under the bulb. At night drop temperatures by 10 °F (6 °C).
What humidity do Yellow Headed Water Monitors need?
Aim for 60–80% humidity with a night spike. Use a high-humidity mix of coir and orchid bark, a large cool-side water bowl for drinking and bathing, and a light evening spray. Always treat water with a de-chlorinator such as Reptisafe, or use bottled water.
When can I start handling my Yellow Headed Water Monitor?
Allow the monitor to settle and begin eating regularly before handling — we recommend at least two successful feeds first. Initial sessions should be 5–10 minutes only; lengthen as they become more comfortable. Always wash or disinfect hands before and after handling. Do not use aerosols or plug-in air fresheners near the enclosure.
What UVB do Yellow Headed Water Monitors need?
A T5 unit with a 6% UV tube mounted on the ceiling — straight across the top or diagonally (diagonal often places the power unit toward a rear vent). Replace the tube every 12 months because UV output degrades. Match UV on/off to the heat schedule: about 12 hours in winter and up to 16 hours in summer.
What do Yellow Headed Water Monitors eat?
Insects (crickets, locusts, Dubia, calci worms as staples; wax worms, mealworms and Morios in moderation) plus vegetables where accepted — most will not eat them. They are also great meat eaters — try mice, chicks, small amounts of cat food, whole fish and eggs. Dust every feed with a 4:1 calcium : Nutrobal mix. Use the “method of 5” while settling; settled animals may take 10–20+ crickets daily. Adults often need one or two food-free days per week. Hunting and chasing food provide exercise and enrichment.
Next steps
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