A List of Safe Woods for Rats and Mice (And Unsafe Woods to Avoid)

by Alison Blyth
Safe woods for rats and mice

The content of this article was contributed by guest author (and rodent wrangler extraordinaire) Beri Instone

Branches and wooden toys are a brilliant way to enrich the in-cage life of rats and mice. They’re great for encouraging climbing and clambering around, and offer a really nice range of smells and textures to interact with. They are also good for nibbling and gnawing – and there are few things rats and mice enjoy more than finding something to gnaw on.

But before we start – some important safety/ legal notes…

Safety notes

For pet safety

Make sure you are 100% sure what species the branch is from before giving it to pets (see the safe woods list below). It is ultra-important to know exactly what you’re giving them, so you can make an informed decision on safety. This means that simply grabbing a branch from the ground is a bad idea, and unless you’re very skilled, avoid trying to ID what species a tree is in winter (there will be no leaves to help you out, and many of the safe species do drop their leaves).

Avoid trees which are near heavily used roads (pollution) or have been sprayed with chemicals.

For your safety

Before collecting any branches, assess the situation for safety. Is it safe and appropriate to collect from that tree? What tools are required, and do you know how to use them safely? Do you need personal protective equipment? Where necessary, seek assistance from someone trained in pruning. Do not climb trees to obtain branches. Be aware of your own safety and that of others around you.

Check the foraging laws of your country/area, as some trees are included in these types of legislation. And always get permission from garden owners before pruning their plants.

For tree safety

For the health of the tree, branches bigger than the size of your index finger should only be pruned off in the colder months of the year. This is because by pruning a branch you’re basically creating an open wound. Think of tree sap like human blood – in warmer growing months the sap is ‘up’ [technical term], and any infection is more likely to spread. In winter the sap retreats, meaning the tree wound can heal more safely.

It’s also important that when you cut a branch, you make the cut at an angle that isn’t horizontal to the ground (as vertical as possible is best). This ensures any rain will drip off, rather than collecting and rotting the tree.

Foraging for enrichment is fun, but it should be done in an environmentally conscious way; don’t leave a path of destruction behind you.

Drying out wood and making safe

You shouldn’t just give newly cut branches to your pets. First, they need to be made safe (any bugs or parasites killed) and then dried out.

The best way to clean the branches at home is to use wet heat:

  1. put your branch in a bath or sink, boil a kettle, and gently pour the hot water over the branch (be careful to avoid splashing yourself or others).
  2. You then need to dry the branch out to the point that the sap goes from being a green layer under the bark, to turning brown too – how long this takes depends on how big the branch is and how warm your house is, but 2-6 months is a good guideline. 

Some people use bleach as part of the cleaning, but remember wood is a porous material and so properly rinsing it afterwards is nigh on impossible. On balance, exposing your pets to bleach is likely to be the more dangerous option. We feel that if bleach is needed to clean a branch, then that branch wasn’t safe to collect for pets in the first place. The decision on whether to remove lichen is purely aesthetic; it’s not dangerous for your pets to nibble, in fact most times quite the opposite as it’s historically a pretty nifty food source. Extra enrichment!

Much info online advises freezing wood to make it safe, but this does practically nothing as in many areas of the world, trees and parasites have adapted to sub-zero conditions as a natural part of their life cycle. Some sources alternatively recommend using the dry heat of an oven. We don’t suggest this for two reasons. Firstly, you’re limited on branch size in terms of what you can fit. Secondly dry heat can change the cellular structure of the wood, cracking the outer bark. Cracks in bark = easier for pee and poo moisture to permeate in later = branch gets very stinky very quickly = a lot of work for nothing.

Fine little twigs are usually safe to be fed straight away, or after about a week drying out in the home. These are the sort of size that won’t hold the weight of a mouse, much less a rat, but they are great to just put on the substrate as a nibble toy. They usually get completely demolished before too long.

Safe woods to use in a rat or mice cage

Cleaning twigs and branches between uses

Rats and mice do tend to pee everywhere, so wooden toys and branches in the cage will get dirty. To clean them you can do something similar to the initial cleaning above with soaking and then leaving to dry, although if the bark has been nibbled off, the less waterproof inner part of the branch will take longer to dry.

Many people find it more effective to just wipe clean the surface of branches – this removes the worst of the dirt, but doesn’t completely strip scent marking away, meaning your rats/mice won’t go wild with re-marking.

If you have access to outside space then a really nifty thing to do at less frequent intervals is simply to leave the wood outside for a bit, to allow smells to dissipate. A couple of weeks outside and then drying inside and you’re good to go!

Which types of wood are safe?

Not all types of wood are equal, and some can be toxic to our pets so it is important to know which types are safe and which aren’t.

There are two main categories of wood, and it’s important from a rodent enrichment and safety point of view that you understand the difference:

  • Hardwoods are grown from trees with normal flat leaves. These trees grow slowly, which results in harder and stronger wood, hence the name.
  • Softwoods are grown from conifer trees, which have needles instead of normal leaves (think Christmas trees). These trees grow really quickly, so are the backbone of the commercial timber industry.

Hardwoods are the category we focus on for tree species that are safe to use with rats and mice. A general rule of thumb is that wood from trees which are listed as safe for rabbits to eat, and trees which people can safely eat the fruit of are safe to give. Rats and mice are omnivores like people, and have much more robust digestive systems than rabbits. Additionally, they’ll only really be nibbling the wood, rather than scarfing it into their faces as a meal like rabbits do.

However, when looking at any lists of suitable woods online, it is very important that the list gives the Latin names of the tree too. A Latin name refers to a specific species of tree, while common names vary internationally and may refer to a safe tree in one country but an unsafe tree in another.

Our favourite woods to give rats and mice:

  • Apple (Malus domestica) – super tasty wood, will likely not last very long before chewed up
  • Hazel (Corylus avellana) – another tasty tree, but big branches last well
  • Ash (Fraxinus excelsior) – particularly great for challenging rats as small diameter branches are exceptionally strong, and are famed for bending rather than snapping. Branch wood is very smooth in texture, so easy to clean.
  • Birch (Betula sp.) – mice and rats find birch super tasty, I (Beri) try and always have a few twigs in the substrate for nibbling
  • Hawthorn (Crataegus monogyna) – thorns should be removed for safety, although harvesting the new year’s growth from hedges results in twigs with far fewer thorns on than from trees. Very tasty.
  • Elder (Sambucus nigra) – lovely texture to the bark, so great for rats who need a bit more grip
  • Alder (Alnus glutinosa) – one of the few deciduous trees which produce cones, for extra enrichment 
  • Willow (Salix sp.) – commonly sold commercially as nibble twigs, you should take particular care with these species that the wood is fully dried out before giving it to pets.
  • Cherry, plum, peach (Prunus sp.) – these woods can have a fabulous texture for climbing, and aren’t very palatable to mice and rats, so a big branch can last years once dried.
  • Buddleia (Buddleia davidii) – lots of people have these growing in their gardens as the flowers are excellent for butterflies. Try to use the older woody growth rather than the newer green growth.
  • Beech (Fagus sylvatica) – forageable branches are more likely to be mouse-size than suitable for rats.
  • Hornbeam (Carpinus betulus) – loved by squirrels (also rodents) for the tasty bark, but can often have fungal infections. Extra tree-health care needs to be taken with these.
  • Lime [UK] or Linden [US] (Tilia sp. and Tilia x europaea) – takes longer than average for branches to dry out, and often has a high parasite load
  • Rowan, Whitebeam (Sorbus sp.) – many of these trees don’t grow very big, so will be more suited for occasional use with mice, rather than for rats, or with high frequency.

Unsafe woods that you should never give to your pets

TOXIC broadleaf trees which should NEVER be given to rodents:

  • Box 
  • Dogwood
  • Laburnum
  • Privet
  • Horse chestnut
  • Eucalyptus
  • Laurel

Please note this is not a complete list, rather it focuses on the woods commonly asked about on rat care forums. If you are not certain a wood is safe for your pets, or if you are not certain of the ID of the tree, do not use it.

Softwoods

These trees are not suitable to collect branches from for enrichment purposes. Trees and woods in this category include spruce, pine, and cedar.

This is because the wood is incredibly oil-rich and the bark has a very different structure to hardwoods (the tree uses the oils to stop parasites, infection and other harm from coming to itself). The oils in the woods contain compounds called phenols which can be toxic to rats and mice, and it is not possible to safely treat them at home.

So what about softwood shavings as substrate?

The difference here is that commercial operations can use MUCH higher heats to treat the wood than is possible at home. And these very high heats can remove the phenols making the wood safe. This is why it’s important to make sure that any softwood shavings you buy have been heat treated (e.g. kiln dried) rather than being raw. 

In addition to being heat-treated, any wood shavings that are going to be used for rats and mice should be dust-extracted. Dust, from any source be it wood or paper, is bad news for rodent respiratory systems which are highly sensitive. The best wood-based beddings are the large kiln-dried and dust extracted flakes originally sold for use with horses.

But all my commercial rodent toys are made from these softwoods, are they safe?

Trees which are going to be turned into timber go through a completely different set of processes to anything we can do at home. All of the moisture (both water and oil) is removed from the wood to make the product safe, cheap, and easy to manufacture. So, pine toys from pet shops and home-made toys using pine from the hardware store are generally safe.

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12 comments

Eliot Daoust July 1, 2020 - 10:45 pm

Just a quick comment to tell you that I think your website is incredibly well done, full of great infornative, well-organized goodness for anyone feom begginer to experienced owner. Thanks for the obvious hard work you put into informing the pet rat (and mice) comunity!

Reply
Monika July 2, 2020 - 11:19 am

Thank you for such a wonderful comment 🙂 We are very happy to see people appreciate what we do here 🙂 You made our day!

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Gabrielle July 6, 2020 - 12:53 am

Thank you for making this guide! We found a lime/linden branch today, but weren’t sure if the high parasite load that you mentioned will be an issue. Can we sanitise it by pouring boiling water over it, or does it need some sort of additional treatment? Also, for any type of wood, do you prefer to leave the bark on or strip it off?

Reply
Alison July 8, 2020 - 6:33 am

Hi Gabrielle,
I’ll forward your question to Beri for a more expert answer. But I don’t think there is a different treatment, it’s more a case of ensuring the cleaning and drying steps are dome thoroughly.

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Alison July 8, 2020 - 10:42 am

So feedback from Beri is she’d have concerns about how long a found branch has been on the ground. But if you are comfortable around that, then the higher parasite load means stripping all the greenery, and then being very thorough about cleaning and drying. As always, I follow a rule of if in doubt don’t use it, as there are lots of other options for engagement.

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Gabrielle July 8, 2020 - 7:12 pm

Thanks for the additional information! The branch was still (barely) attached to the tree, but looked like it had died a while ago, so we’ll discard it to be safe.

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Beri July 8, 2020 - 11:53 am

With regards to bark in general, definitely leave it on. Several reasons for this
1) Most bark is incredibly difficult to remove
2) Most rats and mice absolutely adore stripping the bark themselves, so you’s be going to a lot of effort and blood, sweat, and tears and would end up with a less enriching product at the end of it.
3) If the bark is easy to remove then the branch is probably diseased or already well on they way to decomposition. It should be discarded and not used for caged pet enrichment.

Given your two questions come together about a branch you “found” I would leave it.

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Michelle Woodby July 8, 2020 - 3:29 am

We need to know whether shagbark hickory is safe. We live in the north east US.

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Alison July 8, 2020 - 10:39 am

Hi Michelle, I’m afraid I don’t know (I”ve asked Beri, but she’s based in Europe – I’m in Australia!). I’d suggest checking with some knowledgeable US rat keepers, but the rule of thumb is if in doubt don’t use it.

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Beri July 8, 2020 - 11:46 am

Hi Michelle,
Your question is covered in the article, specifically this section:
“A general rule of thumb is that wood from trees which are listed as safe for rabbits to eat, and trees which people can safely eat the fruit of are safe to give. Rats and mice are omnivores like people, and have much more robust digestive systems than rabbits. Additionally, they’ll only really be nibbling the wood, rather than scarfing it into their faces as a meal like rabbits do.

However, when looking at any lists of suitable woods online, it is very important that the list gives the Latin names of the tree too. A Latin name refers to a specific species of tree, while common names vary internationally and may refer to a safe tree in one country but an unsafe tree in another.”

So first steps for you would be:
1) Find out the Latin name of the tree, to be clear that everyone is talking about the same tree
2) Look on any local rabbit-safe forage lists to see if it features. Looking on lists of trees safe for degu is also appropriate, as that community is similarly science-minded and high-forage diets are promoted as best practice.
3) Depending on results there, you may need to do further research into if it’s safe for human consumption or not. And/or if any parts of the tree are used for low-concentration health remedies.

Hope that helps.

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Michele August 18, 2020 - 7:29 am

Hi, you guys are so informative! I have looked everywhere to find what woods are safe to build toys and cage accessories out of for mice. I see many that they can chew on branch-wise but I’d really like to know what kind of lumber is okay, even as far as building a cage or extra levels. Seems that hardwoods would be fine? But are some better than others? Thanks!

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Alison August 18, 2020 - 1:09 pm

Hi Michelle,
I use pine dowel for perches – although pine branches (raw pine) are not safe, the pine dowel and planks sold in hardware stores are fully heat treated and dried which removes the toxic chemicals. I wouldn’t use any wood to build a cage though – they can chew out! I also limit its use in shelves as all wood will soak up pee with time and get stinky. So I only use wood for removeable accessories I can scrub!

Not all hardwoods are safe – but those on the safe woods list above are. It will depend on what lumber is available in your area (round us it is mainly species of eucalypt, so not suitable)

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