**Background**
Pain management in cats has historically been neglected due to difficulties in recognizing species-specific pain behaviors, as cats often mask signs of pain. While validated pain scales exist, detailed behavioral descriptors (ethograms) for acute pain are lacking. This study aimed to create and validate a comprehensive ethogram of acute pain behaviors in cage-hospitalized cats to standardize terminology and improve pain recognition.
**Methods**
A literature review was conducted across PubMed, Web of Science, and CAB Abstracts (January 2–20, 2023) using MeSH terms: (“acute pain”) AND (behavi* OR “pain scoring system” OR “pain indicator” OR “pain assessment” OR ethogram) AND (cats OR feline). Inclusion criteria encompassed original studies on pain scoring instruments, validation studies, and reviews reporting pain-related behaviors. Exclusion criteria included studies using pain scales as outcome measures, nociceptive testing, chronic pain tools, or surveys. From 53 included articles, an initial inventory of 36 behaviors was drafted by two authors and reviewed by a feline specialist. Behaviors were divided into 10 categories: position in the cage, exploratory behaviors, activity, posture and body position, affective-emotional states, vocalization, playing, feeding, post-feeding, and facial expressions/features. Four expert veterinarians (board-certified feline specialist, board-certified behaviorist, pain management specialist, and feline behavior specialist) independently rated each behavior as (1) not relevant, (2) somewhat relevant, (3) quite relevant, or (4) highly relevant. Content validity was assessed using the item-content validity index (I-CVI), with items scoring >0.67 retained. Face validity was evaluated for clarity and comprehension, and descriptors were revised based on feedback.
**Key Results**
Of the 36 initial behaviors, 24 were retained after expert review. Thirteen items achieved full agreement (I-CVI = 1): positioned in the back of the cage, no attention to surroundings, feigned sleep, grooming, attention to wound, crouched/hunched, abnormal gait, depressed, difficulty grasping food, head shaking during feeding, eye squinting, blepharospasm, and lowered head position. Twelve behaviors were removed (e.g., positioned in front of cage, investigating, scratching, tail twitch, sitting, eating, lip licking). Seven descriptors were reworded; for example, “withdrawing” was moved from exploratory behavior to activity and renamed “withdrawing/hiding,” and “crouched/hunched up” was redefined as “leaning forward with both pelvic and thoracic limbs flexed and head down.” The final ethogram includes 24 behaviors across 10 categories.
**Clinical Implications**
This ethogram provides standardized, evidence-based descriptors for acute pain behaviors in cats, which can reduce inter-observer subjectivity and improve pain recognition, especially for less experienced personnel. Behaviors such as “feigned sleep” (eyes partially closed, ears pulled apart, muzzle retracted) must be distinguished from normal sleep, and “crouched/hunched” posture is a key indicator. The ethogram may be particularly useful for characterizing pain in under-studied conditions (e.g., ocular, aural, dermatologic pain) and can complement existing pain scales like the Feline Grimace Scale and UNESP-Botucatu scale. However, the authors caution that the ethogram is not a pain scoring system and should not guide clinical decisions alone. Further validation is needed to confirm discriminative ability across different pain types and life stages. A video-based training tool is in development. Limitations include a small expert panel (all female) and potential influence of panel size on content validity.