Table 3 . Behavioural and physiological signs of pain in ferrets [ 25 , 28 ] .
Level of pain No pain
Mild pain
Moderate pain
Signs Relaxed , free-moving , normal attention to the environment , playful , inquisitive , interactive
Slight restriction of movement , occasionally licks incision sites , generally quiet attitude
Restriction of movement , hunched posture or attenuated movement when incision site is accidentally touched by cage object , excessive licking at incision site , regular shifting of position , occasional trembling
Marked ( severe ) pain Tense or hunched posture , not moving , constantly trembling , laboured breathing , fixed stare , baring of teeth , aggressive , little or no interest in environment , no response to interaction
Assessing the whole picture
Alternative explanations
There is no ‘ one size fits all ’ pain assessment , and there are alternative explanations for some behaviours . A ferret that is exhibiting an unusual facial expression , for example , may be recovering from sedation or anaesthesia , or squinting in bright light . Changes in facial expression occur in many species as forms of communication and displays of emotion . For instance , studies in mice have shown that a facial expression similar to grimacing can occur during territorial encounters with other mice [ 37 ] . Although grimacing can occur during a painful stimulus , the absence of a grimace does not mean the absence of pain [ 38 ] .
A bristled tail can occur in a state of arousal [ 11 ] . In the authors ' experience , whole-body shivering can occur when a ferret is waking up , excited or presented with an alarming stimulus . Shivering can also occur when a ferret is recovering from an anaesthetic and / or very slightly below normothermia . Overgrooming could indicate pain , stress or a health condition . There is some disagreement about sleeping behaviour . A ferret curling up in a ball has been described as potentially pain-related behaviour [ 34 ] . In contrast , Brown [ 29 ] and Mayer [ 30 ] describe a ferret that is in pain as being less likely to curl up in a ball .
Localisation and specificity of pain
It is also important to consider the localisation of the pain . With abdominal pain , curling up may be a protective or guarding behaviour , but in the presence of severe abdominal pain , the ferret may no longer be able to curl up , leading to a prone posture , or a semi-curled-up position . With spinal pain , it may be difficult for the patient to curl up at all .
Owners often bring their animals to the veterinary practice because they notice a change in behaviour , so if there has been a change in a ferret ' s normal habits , posture or position , it is advisable to evaluate the patient . Even subtle changes in behaviour , such as the way a ferret accesses its nest box , possibly to avoid touching an incision site , may be significant [ 25 ] .
Weight loss can be considered a non-specific sign of pain . Nevertheless , it is worth remembering that ferrets have seasonal weight changes . Their weight is generally heavier in the winter months , sometimes by up to 40 %, but this is less pronounced in indoor ferrets or surgically neutered ferrets [ 39 ] . They are also sexually dimorphic ( males are heavier than females ).
Hindlimb paresis can occur with a multitude of conditions . It is necessary to rule out hypoglycaemia , musculoskeletal disorders , abdominal pain or organomegaly [ 40 ] . Hindlimb paresis may also be immunemediated or related to infection , trauma , toxicity , neoplasia , spinal defects , or a metabolic or degenerative condition [ 40 ] . So , while it is important to consider , assess and address pain in a ferret with hindlimb weakness , it is also important to exclude other comorbidities .
Signs of chronic pain in ferrets
Chronic pain in ferrets can be difficult to assess ( Table 4 [ 10 – 12 , 15 – 17 , 20 , 21 , 26 – 36 , 41 ] , page 27 ), particularly as these animals spend a large part of their day sleeping . When they are awake , their short legs , fast , sporadic movement and low carriage make limping difficult to assess . Despite a lack of scientific data , it is normal to assume that the behaviours associated with chronic pain in other mammals may be applicable to ferrets , such as a propensity to become irritable , aggressive , withdrawn or less active . These behaviours , along with changes to mobility and alterations to daily routines and personality , may be perceptible only to an observant owner .
Ferrets are ‘ geriatric ’ by 3 years of age , so regular veterinary health checks are advised from this age to detect issues at an early stage [ 41 ] . However , chronic pain is not exclusive to geriatric ferrets : any unmanaged or poorly managed acute pain can become maladaptive and turn into a chronic pain condition ,
26 Veterinary Nursing Journal