Three Lions Die from Suspected Heatstroke at Tokyo's Tama Zoological Park

Three female lions died at Tama Zoological Park in Hino, Tokyo between July 28 and August 2, 2026. The deceased lions were aged three to 15 years old and were named Mugi (age 3), Ichigo (age 11), and Luena (age 15). Autopsies revealed dehydration and multiple organ failure in all three animals. Heatstroke is the suspected cause of death, marking the first time lions had died due to heat at the zoo.

As of July 2026, Tama Zoological Park housed 16 lions in total — five males and 11 females aged one to 20 — and 10 of them developed symptoms including loss of appetite, fatigue, and decreased activity beginning in mid-July. The lion exhibit and lion bus service at the zoo were suspended beginning July 23 due to the heatwave making lions ill.

Tama Zoological Park has been breeding and exhibiting lions since 1964 and offers a safari-style bus service for visitors. The zoo houses approximately 260 species of animals, and lions have been a key attraction for over six decades.

The deaths occurred during record-breaking summer temperatures in Japan. Parts of the country reached 40°C in recent weeks, prompting Japan to introduce an official designation called 'cruelly hot day' for temperatures of 40°C or above. The country's highest-ever recorded temperature of 41.8°C was measured in Isesaki in August.

Center-left outlets provide detailed reporting on the zoo's medical response and environmental countermeasures. Zoo staff administered fluids, medication, vitamins, ventilation, and water cooling to sick lions. Remaining lions were moved to a private enclosure with portable air-conditioners and industrial fans, and other countermeasures including water sprinkling and improved ventilation were implemented. As of early August, three lions (two males and one female) remained unwell and unable to stand, while four lions had shown signs of recovery and six had remained in good health throughout.

Center-left outlets report that Japan's humid heat is different from the dry heat of Africa, which zoo officials noted as a factor making Japan's conditions more dangerous for lions. A sudden spike in temperature in mid-July, after the rainy season ended in late July, may have prevented lions from acclimating to the heat. The BBC cited Professor Hideaki Karaki's explanation that lions regulate body temperature by expelling moisture through deep breathing rather than sweating, and high humidity prevents sufficient temperature reduction, impairing their ability to cool themselves.

The lion deaths occurred within a broader human health crisis from extreme heat in Japan. Approximately 18,600 people were hospitalized for heatstroke between July 20 and 26, with 45 pronounced dead on arrival; overall more than 43,000 people have been hospitalized for heatstroke during the summer.

The Guardian reports that Japan experiences approximately 1,300 heat-related deaths annually and the government is aiming to halve that number by 2030. The Japanese government has issued heat warnings, urged residents to stay cool, and encouraged office workers to wear breezier attire, according to the BBC.

The Guardian reports that authorities in Japan have adjusted the timings of cultural and sporting events in recent years because of extreme heat, including the World Cosplay Summit in Nagoya holding its last summer edition. Scientists attribute the increasing frequency and intensity of extreme heat events in Japan and globally to human-induced climate change, according to the same outlet.

The Guardian also noted that South Korea is experiencing a concurrent heatwave, with rising summer temperatures linked to at least 16 deaths.