Genetic and Environmental Causes of Aggression in the Domestic Cat.

Aggression is a behavioral phenomenon observed not only in wild animals but also in companion animals, including the domestic cat. Although feline aggression represents a common welfare and public health concern, its genetic and environmental causes remain not fully understood. The aim of this systematic review was to identify and synthesize the current evidence regarding the genetic and environmental factors associated with aggressive behavior in domestic cats. Original articles published in English between 2005 and 2025 were retrieved from Scopus and PubMed using predefined search strategies. After a two-stage screening and eligibility assessment, 25 studies retrieved though the database searches met the inclusion criteria. One additional eligible study was identified through reference screening, resulting in a total of 26 included studies. No formal risk-of-bias assessment was performed. Findings were synthesized narratively because of the substantial heterogeneity in study design, behavioral assessment methods, and outcome measures. The available evidence indicates that feline aggression is influenced by a complex interaction between genetic predisposition and environmental factors. Associations have been reported with polymorphisms in genes such as OXTR and AR, chromosomal abnormalities, breed, sex, coat color, early-life experiences, owner management, and environmental conditions. Considerable variability in behavioral assessment methods and the absence of a universally accepted classification of feline aggression currently limit direct comparison across studies. Overall, feline aggression should be regarded as a multifactorial trait whose accurate interpretation requires consideration of both inherited and environmental influences.