Hot Weather Management, Heat Strokes and Fly Strike

[Wiebke]

1 How do guinea pigs regulate their body temperature?
2 Heat stroke: symptoms and treatment
- Symptoms of overheating (heat exhaustion)
- Symptoms of heat stroke
- On the spot treatment for heat stroke
- Persistent loss of appetite and lethargy in the days after
3 Fly strike and flesh eating maggots
4 What can I do to keep my guinea pigs cool?
- Give long-haired guinea pigs a short summer haircut
- Bring your guinea pigs indoors during the hot hours of the day (over 25 C / 77 F)
- Where can I put my guinea pigs indoors if I don't have a cage?
- How can I keep my home as cool as possible?
- How can I additionally cool down a cage?
5 How do I feed guinea pigs in hot weather?
- Crucial access to cool water at all times
- Veg and fruit
6 Where to ask questions and get illness support
- Hot weather care questions and feedback thread
- Support for heat related health issues
- Acute heat stroke/exhaustion and fly strike


1 How do guinea pigs regulate their body temperature?

Guinea pigs have evolved to live in groups in thick grasslands in the lower Andes in South America. They come out to browse in part of their territory in the early mornings and evenings when temperatures are at the their least extreme. During the days and nights they retire to abandoned deep temperature controlled sets, tunnels and thick ground covering vegetation well away from the extremes of heat or cold.

Guinea pigs regulate their body temperature via increased blood flow in their ears.
They do NOT pant and they do NOT sweat!
Because they are not losing a lot of water in order to keep cool means that they do not suddenly need a lot more water and veg in hot weather to avoid dehydrating, unlike sweating humans or panting dogs.

However, because guinea pigs cannot adapt as easily to quickly changing temperatures and the extremes of weather, they need a stable environment away from too much heat and cold and big temperature swings.

Key to keeping your guinea pigs cool does NOT require lots of water and watery veg.
But it is ABSOLUTELY VITAL to keep your guinea pigs and their water supply as cool and as fresh as you can to prevent overheating!

Guinea pigs that are born in hotter countries adapt to generally hotter conditions, but they still struggle with the seasonal heat and are very susceptible to sudden cold spells. You often see guinea pigs flopping on their bellies on the floor of their cages in the heat of the day in 'cute' pictures from tropical or subtropical countries showing signs of being overheated.

Please be aware that hot weather is worse for the very young, the very old, pregnant and nursing sows (pregnancy toxaemia!), the ill or frail and those that have an undiagnosed underlying problem. They will need extra attention and care, as much as you can give.

As a rule of thumb: Guinea pigs are fine if you are comfortable.
If it feels hot for you, your guinea pigs are already overheating!
If you are cold and want to grab a coat, your guinea pigs are also cold.

Here is a video of how quickly temperatures rise in a hutch in full sun.
(with permission of Cavy Central Guinea Pig Rescue, Sydney)

A vet is demonstrating in this video just how quickly and how hot it gets in a small confined space on a not particularly hot and breezy day and with the car windows cracked.
He will also tell you what he is experiencing during this time and how it will feel to your pets that are confined in a hot space.
This could be your hutch, conservatory, your lawn run or indoors room in full sun, too!
40 C = ca. 100 F
50 C = ca. 120 F

 

[Wiebke]

2 Heat stroke: symptoms and treatment

Heat stroke can kill or permanently damage overheated guinea pigs.
See a vet ASAP as a life or death emergency!


Symptoms of overheating (heat exhaustion)
- lying on flat on the belly
- lethargic and reluctant to move
- off their food and water, struggling to swallow and to process food
- major weight loss in a very short time


Symptoms of heat stroke
- lying flat on the belly (collapsed)
- unable to move or very wobbly on their feet
- shallow or laboured breathing
- rapid and very weak pulse
- not able to swallow and/or salivating
- twitching or fitting

Your guinea pigs will require subcutaneous fluids and gut simulants; ideally they are kept under close observation and given a check-over before discharge to make sure that they are OK and able to eat normally.
Please make sure that your guinea pigs are not getting any steroids injected by a vet not familiar with guinea pigs; in rodents this slows down the organs further. Always ask your vet before they inject anything.


On the spot treatment for heat stroke
- Bring your guinea pigs indoors ASAP!
- Soak a towel in tepid/warm room temperature tap water (NOT iced or fridge cold water!) and wrap the piggy in it, loosely at first in order to not shock the system.
- Or gently sponge the piggy down with fresh water from your tap. Lower the body temperature gradually in order to not cause the heart to stop.
- If your guinea pigs are still able to stand on their own, place them a bowl with 1 cm (leg height) tepid water until they perk up.
- NEVER plunge an overheated guinea pig into cold water. It can cause a fatal cardiac arrest!
- Do NOT try to syringe any cold water or stuff cool veg or fruit in the mouth in order to revive it. Your guinea pig can asphyxiate (die from choking) because it struggles to swallow with heat stroke and the gut may have stopped moving.

Recovery, if there is any, should be quick and pretty dramatic. Support the piggy as soon as they are trying to get back on teir feet and stop the cooling down instantly to avoid the piggy from getting a chill instead.
If your guinea pig is not perking up quickly, then they need to be raced to the vets in the small hope that it can still be saved.

Then call your closest vet clinic to ask to be seen as an emergency. Even if your guinea pig is only overheated, they will still require sub-q fluids with electrolytes and gut stimulants.
Remember to cool down your car as much as possible before you set off and to add a bottle of frozen water in a sock to the carrier; place your piggies right next to it.
Travelling with guinea pigs (contains more hot weather travelling tips)

If you cannot be seen by a vet straight away, offer your guinea pigs as much water as they will actively take from a syringe; do not force any water or fibrous syringe feed into a guinea pig that struggles to swallow! Add electrolyte powder from your first aid kit or your pharmacy as specified on the package (UK: dioralyte / US: pedialyte) to the water. It is not as effective as having the fluid injected under the skin where it can be absorbed directly by the body, so if you CAN see a vet please do so as soon as possible!
Ask your vet to also check the heart and the guts for potential full or partial GI stasis.


Persistent loss of appetite and lethargy in the days after
If your guinea pigs remain weak and show symptoms of partial gut stasis (very little or no gurgling in the belly), then you will need to step in with syringing fibre and water in very small portions they can hold in their mouth and swallow (0.1-0.3 ml per mouthful). Wait before any ffod/water has gone down before you offer more - as much as your piggy will take in one session. Feed every two hours round the clock until they are back to eating fully again by themselves and maintaining their weight. Seek vet care for reydration and gut stimulants as well as heart monitoring.

Don't be deceived: Your guinea pigs won't be out of the woods until they are back to eating normally.
The after-effects of a heat stroke can sadly kill even days after the stroke.
Digestive Disorders: Diarrhea - Bloat - GI Stasis (No Gut Movement) And Not Eating
All About Syringe Feeding and Medicating Guinea Pigs with Videos and Pictures
How to Improvise Feeding Support in an Emergency
Emergency, Crisis and Bridging Care until a Vet Appointment

 

[Wiebke]

3 Fly strike

Summer and hot weather also brings out flies that lay their eggs into living flesh. This is called fly strike. It can happen outdoors, but occasionally also indoors.

Please check any piggies at risk (the old, frail piggies that cannot clean their genitalia by themselves, guinea pigs with mobitility issues, bleeding and open sores) at least once daily and always when you bring them indoors from a trip to the lawn for slightly raised red or white dots around the genitalia or open sores.

Also keep in mind that fly strike can also happen indoors.

Fly strike can kill! It is classed as a life and death emergency at any time of the day.

If you discover maggots in your hutch or cage, please clean and disinfect it thoroughly.

Check your piggies asap or have them vet checked for symptoms of fly strike. Clean your hutch and shed very regularly in hot weather in order to not attract vermin anyway.

By far not all maggots you can find crawling in your hutch have been laid by blow flies, but you need to make sure of that!

More information on fly strike and how to minimise the risks via this link here: Fly Strike

 

[Wiebke]

4 What can I do to keep my guinea pigs cool?

Give long-haired guinea pigs a short summer haircut
A popcorning piggy that has been freed from the equivalent of being stuck in a ski suit on a tropical beach will tell you exactly what relief a short haircut during the hot season is for it! Guinea pigs do not have long hair originally; it has been bred into them.
Please respect their species needs during heat waves and spikes. It can make the difference between surviving a heat stroke or not.
By autum the hair will have grown back anyway!
An Illustrated Guide to Hair Cutting


Bring your guinea pigs indoors during the hot hours of the day (over 25 C / 77 F)
Please keep in mind that a hutch or an uninsulated shed is around 10 C warmer inside than outside temperatures are and that a run on the lawn is still exposed to any hot breeze even if it is in the shade of a large tree.
Bring your guinea pigs inside the house for the hottest hours/the day, especially when you are away.
Put your guinea pigs out on the lawn or back into the hutch while it is cool and shady in the early morning and late afternoon evening, especially when outdoors is cooler and fresher than inside!

Guinea pigs and their housing should never be exposed to strong sunlight!
Even thick shade is not enough protection during the hottest hours, especially if there is a hot breeze which can easily exceed 50 C / 120 F.

Ground and inside temperatures on a pleasant, sunny day (at 25 C / 77 F)

(With permission of East Anglian Guinea Pig Rescue, temperatures taken on a warm but not record hot day with ca. 25 C / 77 F indoors in comparison)

Please keep any water bottles out of full sunshine at all times. Not only will the water be too hot to drink, it can even set a hutch alight! You may find this link here a wake up call: water bottle sparks hutch fire


Where can I put my guinea pigs indoors if I don't have a cage?
You can set up a lawn run with some old old beach towels on a wipeable surface (best a kitchen or bathroom floor) or even let your guinea pigs camp in the bathtub in a pinch.
More ideas for temporary accommodation in this thread here: Temporary Housing Solutions?


How can I keep my home as cool as possible?
- Close your windows, draw your curtains and pull any blinds wherever the sun is going to hit during day/while you are away. Curtains and blinds are acting as an additional insulation.

- You need to close all windows as soon as outside temperatures get hotter than the temperatures in your home. it may be uncomfortable but a there is only so much a closed box can heat up while a strong sun-heated breeze is much hotter (40-50 C) and can still penetrate into the shade and kill.

- The less sun gets on your window glass and into home the cooler it is going to stay inside.
Open your windows on the shady side once the outside temperatures are no longer hotter than indoors.

- Move any cages out of direct sunlight! Keep in mind that the sunlight moves around while you are out of the house for the day.

- Air your house or flat as much as possible during the cooler hours and overnight. The cooler it is indoors in the morning, the less your living quarters can heat up during the day. If you can, create as may cross drafts as possible in order to catch any breeze.

- Fans, portable or mobile air conditioning units or fixed air conditioning can of course also help.
Please make sure that your guinea pig cage is NOT in the direct full blast. It can cause URI (respiratory infection) or breathing problems.

BIG NO NO:
Please do NOT use a fan in combination with an open window to cool down your guinea pig room in the heat of the day. All you do is fan even hotter air into the room and expose your guinea pigs to heat stroke. Sun-heated air can surpass 50 C!

- During extreme weather treat your windows on the sunny side as you would a greenhouse in hot weather - prevent the sun getting to any glass and if possible wet any fabrics to additionally cool the windows by allowing the evaporating water to create a layer of cool air between the fabric and the window glass, which is very effective.
This REALLY makes a difference in how much your home can heat up inside. It may be unsightly, but it is cheap, effective and, compared to high energy solutions, a lot more environmentally friendly.
You can wet your sheets shortly in your cold shower or use a spray bottle to moisten them repeatedly even when there is a hope pipe ban in your area.


There is a reason why houses in warmer climes have shutters on the outside of their windows, overhanging roofs and verandahs - or otherwise thick walls without out much in the ways of windows on the outside with doors opening around shaded courtyard.

Since the UK has been traditionally a very moderate country where rain and dull days rather than temperature extremes have been the main consideration, the vast majority of houses are generally not laid out for the challenges of climate change with bigger extremes from frost periods/snowfall to storms/rainfall and of course heatwaves and heat spikes. Anything we can do with a combination of low impact measures will benefit not just us, our purse but also out environment for the future.

Here are my field test results from a record breaking day in the UK (25th July 2019) with repeatedly dampened sheets:
Outside: 9.30 am - 27 C ; 11.30 am - 30 C ; 3.30 pm - 34 C (temperatures eventually climbed over 35 C)
South-facing kitchen: 9.30 am - 23 C ; 11.30 am - 25 C ; 3.30 pm - 26 C with the sun moving off
Piggy lounge on the right with thick inside curtains and fan: 9.30 am - 23 C ; 11.30 am - 24 C ; 3.30 pm - 25-26 C (lower in fan area)
The more you can keep indoors temperatures around ca. 25 C max at the start of a heat wave/spike and not climbing over 30 C in subsequent days as the heat will slowly build up further, the more of a chance your piggies have to adapt to the hotter temperatures slowly and avoid heat exhaustion or a stroke.
It is temperatures over 30-40 C (i.e. over 90-100 F) that are the real killers for guinea pigs that have not had a chance of adapting to them slowly, like guinea pigs in tropical climates.


How can I additionally cool down a cage?
- Fill a large empty plastic soft drinks bottle 3/4 full of water (remember - ice expands!) and freeze. Wrap in a towel and place in the cage if you are out for the day. Smaller pint sized bottles are useful for regular replacement or travelling; pull an old sock over them.
- You can also rope in any freezeable cool bag blocs, ice packs or even water filled plastic gloves that you tie off and stick in the freezer etc. Always cover any frozen articles in fabric and allow 10% more space in the container as water expands when it freezes.

- Cool your snugglesafes in the fridge (please not in the freezer). My frailer oldies love sleeping on them, covered with some fleece. They need replacing every 2-4 hours, but they are gentler.
- A large or some cheap ceramic tiles are also good at sucking up body heat.

- Evaporating water cools the air around it.
Dampen some fabric (sheets, fleeces, towels) but not so much that they drip and drape them over the cages or around the them, especially where air from a fan or an a/c unit can hit them.
Spraying any net curtains with water can also help cool down a room when there is a breeze in the evening.
This is not recommended in high humidity/tropical climate, but is effectful in dry/desert conditions.

If your guinea pigs are staying away from cooling elements, they aren't overheated!

PS: PLEASE PLEASE PLEASE do not force your guinea pigs to swim for their lives to keep them cool. For them it is the most frightening experience and it is no fun paddling for their lives!
It can lead to cardiac arrest, secondary drowning from water in their lungs preventing oxygen exchange and them dying.
Can And Should Guinea Pigs Swim?

 

[Wiebke]

5 How do I feed my guinea pigs in hot weather?

Crucial access to cool water at all times
Guinea pigs don't need to drink loads more in hot weather, but they need to have access to cool, fresh water at all times!

- You can keep a jug of tap water (filtered or not) or your bottles of low calcium water in your fridge.
If you are out of the house for the day and don't have reliable air conditioning, adding some crushed ice can help to keep the water cooler for longer.
Replace the water with fresh cool one when you come home in the evening and if possible throughout the hotter hours in the afternoon if you are at home.

- Daily bottle cleans: Please keep your bottles and nozzles cleaned daily; bacteria multiply very quickly in hot conditions!
If your guinea pigs are in a place where you can't fix a bottle, use a bowl.

- Bottle insulation: You can insulate your water bottles further by pulling a sock over them. Remember: insulation works both ways - it slows down the flow from hot to cold whether that is in cold or in hot weather!

- Large piece of cucumber for longer absences or travelling: If you are out for the day or are travelling in hot weather, then a larger chunk of cucumber is a good additional source of fluid. It will hold the fluid and stay cooler for much longer if you do not cut it up into small pieces. It makes a good back up for potentially overheating water bottles and is a safe way of providing fluid that cannot spill when you are travelling with your guinea pigs.


Veg and fruit
Please do not feed more or differently to their normal diet.
Too much veg and fruit causes fermentation in the gut and can lead to diarrhea or bloating.
You should not feed more veg and fruit than normal, but you can rather serve any veg in the morning in one large piece that stays cool for longer; especially a larger piece of cucumber from the fridge. That is also the best method of keeping a guinea pig hydrated when you are travelling.

However, a bit of cool water melon (including the rind) on a hot evening is a welcome treat! But please count it into the daily veg allowance.
Please do NOT feed any frozen veg; greedy piggies have done themselves serious harm when their lips and tongue got stuck to the ice. Veg straight from the fridge is as cool as it should get.

Please keep in mind that all veg and fruit consists mostly of water and that your main aim is too keep your guinea cool, but not over-watered!

However, if you are out during the whole day or need to travel with your guinea pigs, a large chunk of cucumber will stay cooler for longer and can still provide fluid when your bottles may have become too hot to drink from or are not an option.

If your guinea pigs suddenly stop drinking water but are still eating normally, you are feeding too much watery veg. Piggies don't get any thirstier just because you offer more water in edible form.
Be aware that overfeeding fresh veg can cause diarrhea or bloating.
More information on feeding in hot weather in this link here: The temptation to overfeed watery veg and fruit in hot weather!

 

[Wiebke]

6 Where to ask questions and get illness support

Hot weather care questions and feedback thread
For more 'real time' feedback on testing out measures by our forum members and all those little and larger questions around hot weather, when it gets critical for guinea pigs, working out and implementing practical alternatives and personal solutions and optimising what you can do without increasing your electricity bills or your environmental footprint massively, please see our practical forum support thread at the top of our Guinea Pig Chat section. You will find it very helpful!

Please read through the thread first; your question may have already been answered but you are welcome to ask any questions or concerns you have, however major or seemingly insignificant. You can be sure that you are not the only one and that others will be glad for you asking a particular question or concern.
Here is the link to our heat care questions guide: Hot weather warning for the UK - plan now to keep your piggies safe!

Support for heat related health issues
We have a specially monitored Health&Illness Care section for support during recovery.

Acute heat stroke/exhaustion and fly strike
If you notice symptoms of acute heat stroke or exhaustion or fly strike (see chapters 2-3), please contact your vet clinic asap before opening a support thread on the forum. Your piggies will need sub-q fluids immediately as well as a health check for the heart and gut.

Guinea pigs not well in the days after
The same goes if your piggies are apathetic, have loss of appetite/weight loss/small and less poos (potential GI stasis, i.e. no gut movement - keep in mind that the poo output always runs 1-2 days behind the food input) - i.e. they have symptoms of an unrecognised and untreated heat stroke or exhaustion, or of greater damage to the body.
If your piggies have diarrhea or bloating, then they have likely had too much fresh fruit and veg.
Please contact a vet and step in with life-saving feeding support asap.

Here is more detailed practical care advice and information on digestive problems and how to support feed
- Digestive Disorders: Not Eating - Diarrhea - Bloat - GI Stasis (No Gut Movement)
- All About Syringe Feeding and Medicating Guinea Pigs with Videos and Pictures (includes tips for how to improvise in an emergency)
- Emergency and Crisis Care as well as Bridging Care until a Vet Appointment