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Suspected heatstroke kills three lions at Japan zoo

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Images provided by Tokyo Zoological Park Society show lions, from left to right, Mugi, Ichigo and Luena, who died within a week of suspected heat stress in Tokyo.

TOKYO, Japan -- Three lions at a Tokyo zoo have died from suspected heatstroke and others are under treatment, a spokeswoman said on Tuesday, with the big cats struggling with high humidity.

Japan sweltered through its hottest summer on record last year and parts of the country have hit 40 C in recent weeks, qualifying for the new designation “cruelly hot day,” with thousands of people hospitalized.

Ten of the 16 lions in Tama Zoological Park have suffered symptoms such as “loss of appetite and decreased activity” since mid-July, and three lionesses died, the zoo said in a statement.

One three-year-old female died on Tuesday, another aged 11 died on Friday, and the third on Sunday aged 15.

Mugi This image provided by Tokyo Zoological Park Society shows lioness Mugi, who died of suspected heat stress in Tokyo.

The Tama Zoological Park said the lion enclosure, where visitors can normally be driven around in zebra-pattern “safari” buses, was closed to the public until further notice.

“According to our veterinarian, the cause of the deaths is suspected to be heatstroke” because dehydration and multiple organ failure were observed, a spokeswoman told AFP.

“Even though lions are thought to be resistant to heat, zoo keepers have been strengthening countermeasures to cope with Japan’s summer heat in recent years. Heat here comes with high humidity; that is different from heat with dry air in Africa,” she said.

Luena This image provided by Tokyo Zoological Park Society shows lioness Luena, who died of suspected heat stress in Tokyo.

The spokeswoman said the heat “arrived suddenly” this summer after the rainy season ended in late July.

“We are strengthening measures against the heat (further), sprinkling water, improving ventilation and installing spot air conditioners,” she said.

Several lions are still being treated, she added.

‘Profits’

Animal rights group PETA said the lions named Mugi, Ichigo and Luena “were born, lived, and died in confinement, deprived of everything that makes life worth living for a wild animal.”

“Zoos are not rescues or sanctuaries; they exist to display animals for profit, not to put animals’ needs first,” PETA said in a statement.

Close to 18,600 people were taken to hospital for heatstroke between July 20 and 26, with 45 of them pronounced dead on arrival, according to the fire and disaster management agency.

Japan experiences about 1,300 heat-related deaths annually and is aiming to halve that number by 2030.

Ichigo This image provided by Tokyo Zoological Park Society shows lioness Ichigo, who died of suspected heat stress in Tokyo.

Scientists say human-induced climate change is increasing the frequency and intensity of extreme heat events in Japan and elsewhere.

Its highest recorded temperature of 41.8 C was registered on August 5, 2025, in Isesaki, north of Tokyo.

Authorities have adjusted the timing of several cultural and sporting events in recent years because of the heat, including the World Cosplay Summit in Nagoya, which held its final summer edition last weekend.

By Kyoko Hasegawa, AFP