Small Pet Body Language: Signals, Stress Signs and Hidden Pain

This page is for owners of the six small mammals most often kept in cages and pens. It helps you decide whether something you’ve just seen is normal, a sign of stress, or a reason to call the vet today. Several of these species show contentment and pain with the same behaviour at a different intensity, so the context column matters.

Signal, meaning and when to worry

Species	Signal	Usual meaning	When to worry
Rabbit	Binky (leap and twist in mid-air)	Very happy (RSPCA)	Never on its own
Rabbit	Soft, quiet teeth grinding, like a purr	Contented (RSPCA)	If it becomes loud grinding, which can mean pain (RSPCA)
Rabbit	Flopped on its side or stretched out	Relaxed (RSPCA; PDSA)	If it won’t get up or eat
Rabbit	Thumping hind legs	Alarm, fear or frustration (RSPCA)	If repeated with hiding and a tense, flattened body (PDSA)
Rabbit	Boxing, growling, showing front teeth	Feels threatened. Bared teeth is a “final warning” (PDSA)	Back off now. Get a vet check if it’s new behaviour (PDSA)
Rabbit	Hunched, chin tucked in, nose not twitching	Unhappy or unwell (PDSA)	Same day, especially with no droppings for over 12 hours (Merck)
Guinea pig	Popcorning (vertical hops)	Play, mostly in youngsters (RSPCA)	Never on its own
Guinea pig	Circling the enclosure repeatedly	Stress or fear (RSPCA)	If it’s ongoing, review the setup and ask a vet or behaviourist (RSPCA)
Guinea pig	Overdrinking or chewing the water bottle	Stress or fear (RSPCA)	If it persists, as illness is also possible (RSPCA)
Hamster	Asleep all day, active at dusk and night	Normal. Wild hamsters can run up to five miles a day (RSPCA)	If it’s cold and still in winter, which may be hibernation, check it (RSPCA)
Hamster	Fighting with a cage-mate	Solitary species (RSPCA)	Separate them straight away
Rat	Urinating or defecating somewhere new	Frightened (RSPCA)	Return it to its home cage. Small urine marks are normal scenting (RSPCA)
Gerbil	Rapid hind-foot thumping	Perceived threat, or excitement (RSPCA)	If paired with constant hiding
Gerbil	Repetitive digging in one corner	Lack of burrowing depth (RSPCA)	Add depth and hiding places (RSPCA)
Chinchilla	Barking or whistling	Stress or fear (RSPCA)	If repeated
Chinchilla	Chewing its own or a companion’s fur	Stress (RSPCA)	If persistent or causing bald patches
Chinchilla	Racing back and forth on the cage floor	Repetitive stress behaviour (RSPCA)	If it’s a daily pattern

Prey animals hide pain

All six species are prey animals. PDSA notes that rabbits often try to hide signs of illness, and that changes in their body language can be subtle. In practice, by the time a rabbit or guinea pig looks ill, the problem may have been building for days. The most useful thing you can do is learn your animal’s normal routine: when it eats, how many droppings it passes, and where it rests.

Rabbit pain signs

• Posture: sitting hunched, loud teeth grinding, not hopping or moving normally (Merck)
• Output: loss of appetite, or no droppings for more than 12 hours (Merck)
• Face: the Rabbit Grimace Scale was developed in research and scores five facial changes: orbital tightening (narrowed, squinting eyes), cheek flattening, nose shape, whisker position and ear position. Each change is scored by intensity (Keating et al., PLOS One). A single brief squint can be a blink, so look at the whole face over a short period.
• Behaviour: a rabbit that is quieter than usual or tucked up with its nose still (PDSA)

Guinea pig pain signs

Merck lists a hunched posture, rough fur, dull eyes, staining around the rear end, weakness and stomach pain among signs of digestive illness. It warns that some guinea pigs decline quickly and die suddenly. Drooling (“slobbers”) or not eating points to dental disease, often in the back molars even when the front teeth look normal (Merck).

The others

The RSPCA lists the same pattern in chinchillas: when frightened or in pain, they may change their behaviour or start hiding or becoming aggressive. For hamsters, rats and gerbils, the most reliable early signs are changes in routine, such as a nocturnal animal that stops coming out at dusk or a rat that stays in its nest at night. The veterinary care guide covers what to take to the appointment.

Reading signals in context

• The same behaviour can mean opposite things. Rabbit teeth grinding is the clearest example. Soft grinding means contentment and loud grinding suggests pain (RSPCA). Gerbil thumping can signal threat or excitement (RSPCA).
• Time of day changes what’s normal. Hamsters sleep through the day (RSPCA). Rats are most active at night, dawn and dusk (RSPCA). Chinchillas need 12 hours of darkness and sleep undisturbed during the day (RSPCA). A sleepy rat at noon is normal. A sleepy rat at midnight is not. See the nocturnal pet care guide.
• Social signals depend on the species. Hamsters are generally solitary and can be aggressive to other hamsters (RSPCA). Gerbils live in wild groups of two to 15 (RSPCA). A fight means something different in each.

Mistakes that cause problems

• Laying a rabbit on its back to “relax” it. The stillness is tonic immobility, a fear response that the RSPCA describes as stressful and frightening.
• Reading a hiding rabbit as shy. PDSA advises against pulling a hiding rabbit out. Hiding together with a tense, flattened posture is a stress sign, and a sudden change is a reason for a vet check.
• Ignoring loud teeth grinding. It can mean pain (RSPCA), and pain stops rabbits eating. Merck treats loss of appetite and missing droppings as urgent.
• Putting a rat or hamster in an exercise ball. The RSPCA says balls stop rodents using their whiskers to explore, which results in high levels of stress.
• Punishing a nervous animal. The RSPCA says guinea pigs and chinchillas don’t understand shouting and become more nervous.

For behaviour you can shape rather than just read, see behavioural training basics.