Age at death and cause of death of pet rabbits (Oryctolagus cuniculus) seen at an exotic animal clinic in Tokyo, Japan: a retrospective study of 898 cases (2006–2020)

Background: As the quality of care received by pet rabbits improves, the age at death of these animals is expected to increase; however, reliable data on the age at death of pet rabbits is lacking. The present retrospective study aims to clarify the age at death and cause of death of pet rabbits.Materials and Methods: The age at death, cause of death, and clinical details of 898 rabbits that died between 2006 and 2020 were obtained by reviewing paper-based medical records, including necropsy and/or biopsy reports, at a referral exotic animal hospital in Japan.Results: The median age at death in the 898 rabbits was 7 years (interquartile range: 5to9 years), and 18% of all rabbits lived beyond 9 years. The main causes of death included neoplasia (n = 223; 24.8%), gastrointestinal dis-ease (n = 135; 15.0%), bacterial abscess (n = 90; 10.0%), urinary disease (n = 85; 9.5%), trauma (n = 44; 4.9%), and cardiac disease (n = 27; 3.0%). Gastrointestinal disease was the most common cause of death in younger -aged rabbits (4 years or less), while neoplasia was the most common cause of death in the middle to older-aged rabbits (5 years or more).Clinical significance: This is one of the largest retrospective studies on the age at death in pet rabbits conducted to date; thus, the findings will serve as a useful reference for veterinarians working with such rabbits. Nevertheless, additional studies are needed to elucidate differences in the age at death of rabbits according to sex and neutering status.