Regarding the euthanasia of Japanese Red Fox

Hachi, a female Japanese red fox (estimated to be 11 years old) kept in the small animal Japanese Red Fox at Inokashira Park Zoo Zoo (main zoo), had been removed from display since April 5, 2026, due to poor health. Subsequent examinations revealed multiple lumps in her chest that strongly suggest lymphoma.

While continuing treatment and striving to alleviate suffering and maintain quality of life (QOL), recovery is not expected, and the suffering is likely to increase. Therefore, with great regret, we have decided to euthanize the animal on August 17th.

History and previous treatment progress, etc.

Hachi was rescued in Ishikawa Prefecture in 2015 and came to Inokashira Park Zoo in May 2017.

In February 2026, the animal began exhibiting symptoms such as loss of appetite, diarrhea, vomiting, and tremors, so we performed X-ray and blood tests. However, at this point, the tumor was not clearly visible on the X-ray images, and the cause remained unclear. As the same symptoms continued, we suspended exhibiting the animal from April 5th and have been focusing on treatment, including medication.

On April 14th, a follow-up X-ray and ultrasound examination revealed a mass approximately 4 cm in size near the heart. Cellular analysis indicated a high probability of a lymphatic tumor. Steroids were administered to suppress tumor activity, and the appetite gradually recovered.

We continued to administer steroids whenever the patient experienced loss of appetite, but on the morning of August 13th, the patient appeared to be having difficulty breathing, so we performed an examination and found that a large amount of fluid had accumulated in the chest cavity. We performed a procedure to drain the fluid that same day.

Decision and implementation of euthanasia

After draining the pleural fluid, Hachi temporarily recovered, but then respiratory problems reappeared. After comprehensively considering the situation to date and future prospects, it was determined that it would be impossible to alleviate his current suffering through treatment, and that it would likely increase it. Therefore, considering the animal welfare of Hachi, it was decided that euthanasia would be appropriate to avoid unnecessarily prolonging his suffering, and this was carried out on August 17, 2026.

Immediately after treatment, we conduct an autopsy to investigate the lesions and other conditions. The valuable information obtained from the autopsy will be used to improve veterinary medicine in the future in order to save more animals.

We are deeply saddened to hear this news, and we hope you will understand.

If you wish to offer flowers, please enter the park and place them at the memorial monument yourself. Please refrain from placing flowers around the small animal enclosures. In addition, we ask that you refrain from offering items or food to the deceased animals, considering hygiene and the impact on wild animals. Thank you for your understanding.