Mouse & Rat

Mycoplasma pneumonia

SignsSneezing, red discharge around the nose and eyes, wheezing breath sounds, weight loss

PreventionReduce bedding dust and ammonia. Clean at least twice a week. Avoid temperature swings

Mammary tumor

SignsA lump in the armpit, belly or groin that grows rapidly. Most common in females, but also in males

PreventionEarly detection is everything. Palpate the whole body weekly and see the vet while it is still small

Pituitary tumor

SignsHead tilt, clumsy gait, cannot hold food in the forepaws, lethargy

PreventionCommon in older female rats. Watch weight and movement daily and see the vet early for any change

Pododermatitis (bumblefoot)

SignsRed, scabbed or swollen foot pads; reluctance to put weight on the feet

PreventionAvoid wire floors; use soft bedding. Prevent obesity. Keep the floor clean

Kidney failure (senior)

SignsDrinking and urinating more, weight loss, dull coat, reduced appetite

PreventionAvoid high-protein diets; feed species-specific pellets. Health checks from 18 months of age

Skin parasites (mites/lice)

SignsIntense itching, scratch wounds on the neck and shoulders, scabs, hair loss

PreventionQuarantine new animals for 2 weeks. Use bedding from a trusted brand

Tail degloving / tail break

PreventionNever lift by the tail. When catching, cup the body in your hands

First aidIf the tail skin is stripped, keep it clean and see the vet. Dead tissue must be treated at the clinic

Fracture

PreventionMake sure feet cannot get caught in wheel gaps or wire floors. Reduce high places

First aidDo not handle; place in a small box and remove platforms and the wheel. See the vet the same day

Bite wounds from cagemates

PreventionDo not house males together. Introduce new animals after maturity with care

First aidWash the wound and separate the cages. If swelling or pus appears, see the vet for abscess treatment

Burns / electric shock

PreventionCover electrical cords, since they chew them. Position heaters where they cannot be touched directly

First aidTurn off the power before pulling away from the cord. Mouth burns: see the vet the same day. Abnormal breathing: immediately

Rat-bite fever

RouteBites and scratches

PreventionWash wounds immediately under running water. If fever or rash develops, see a doctor

Leptospirosis

RouteContact with urine or contaminated bedding

PreventionWear gloves when cleaning. Do not handle with cut hands. Wash hands thoroughly

Hantavirus infection

RouteInhaling droppings of wild rodents

PreventionNever catch and keep wild animals. Buy only quarantined imported animals

Salmonellosis

RouteOral infection from hands that touched feces

PreventionWash hands after handling. Do not eat right after cleaning the cage

Food

• Mouse/rat pellets as the staple, once a day
• Small amounts of vegetables, boiled egg, etc. as side food 2–3 times a week
• Daily guide: 5% of body weight for rats, 3–5 g for mice

Water

• Water bottle, changed daily. Check for blockage every day
• With several animals, provide 2 or more bottles

Toys & play

• Solid-surface wheel, at least 30 cm diameter for rats, 15 cm for mice
• Tunnels, ropes and hammocks for exploration
• Enrichment: hide treats inside crumpled paper

Nest, bed & hideout

• At least one dark nest box per animal
• Rats love cloth hammocks. Check for frayed threads

Bedding & litter

• Thick layer of paper bedding or aspen shavings
• Never use softwood shavings or cotton nesting material
• Litter tray in a corner with sand or paper litter. Rats learn to use it

Cage / housing material

Wire cage or tall glass tank. Wire spacing 1 cm or less for mice

Size & space

At least 60 cm wide for 2 rats. At least 40 cm wide for mice

Layout

• Place the nest box, wheel and water bottle apart from each other
• Rats need multiple levels for climbing. Put cloth on landing surfaces
• Never use a wire floor; cover it with bedding

Placement notes

• Away from direct sunlight and drafts from heaters or air conditioners
• A quiet spot out of reach of dogs and cats. Avoid vibration

Exercise, free-roam & walks

• Ideally 30+ minutes of daily free-roam time for rats
• Clear away cords, gaps and toxic houseplants
• Mice are quick and hard to catch, so free-roam inside a playpen

Temperature & humidity

Temperature20–26°C. Risk of heatstroke above 30°C

Humidity40–60%. High humidity causes skin and respiratory disease

Summer & winter

• Summer: air conditioning and a cooling plate. No direct sunlight
• Winter: heater and extra nesting material. Below 18°C, add warmth

Nail trimming

Monthly, tips only. If the animal struggles, go to the vet. Older rats' nails grow fast

Brushing, skin & coat care

Not needed. Rats groom themselves. Wipe dirt with a warm damp towel

Other care

Check incisor length. Keep a chew block in the cage at all times. Gently wipe a dirty tail

Protection from predators

• Never keep in the same room as cats, ferrets or snakes
• Never take onto a balcony or outdoors. Crows will attack
• Protect against mosquitoes, fleas and ticks. Beware of parasites from dogs and cats

Foreign-body ingestion

They chew and swallow cotton, rubber bands and plastic. Use paper nesting material only and clear small items away during free-roam time

Being stepped on

They come to your feet, so shuffle when walking during free-roam time. Check under cushions and bedding before sitting

Getting pinched

They get caught in doors, drawers and the cage door. Fix doors open during free-roam time and check with a finger when closing the cage door

Falls

Falls from desks or upper cage levels. If not moving, dragging a leg or nosebleed after a fall, see the vet the same day

Escape

They escape through wire gaps or door gaps. If one escapes, close the room, set out an open cage with favorite food, darken it, and collect at night

Safe release procedure

1. Stop moving and wait a few seconds for it to let go
2. If it does not let go, lower your body toward the cage or a cloth
3. Blow gently on its face or let its feet touch the floor
4. Once released, return it to the nest box and leave it alone for a while

After the release

Wash under running water for 5 minutes and disinfect. If swelling, fever or rash appears, see a doctor. Ask about tetanus too

What to tell the vet & what to bring

Species, age, sex, diet, photo of stool, video of breathing sounds, photo of the lump

Checking consciousness, breathing & heartbeat

• Breathing: watch the chest. Rats 70–110 breaths/min
• Heartbeat: feel with a finger on the chest. 250–450 beats/min
• Consciousness: call its name and touch it; watch for a response

Stopping bleeding

• Press with clean gauze for 5 minutes
• For tail bleeding, apply gentle pressure at the base
• If it does not stop, keep pressing and transport

Transport

• Line a small box with cloth and stick a hand warmer on the outside of the box
• Keep it dark and quiet; transport by car without jolting