Three lionesses at Tama Zoological Park in western Tokyo have died from suspected heatstroke, and several other lions are receiving treatment, as Japan grapples with a punishing summer heatwave. The zoo announced the deaths on Tuesday, attributing them to the extreme humidity that has enveloped the region.
According to a zoo spokesperson, ten of the sixteen lions in the park have shown signs of distress since mid-July, including loss of appetite and reduced activity. The three that died were a three-year-old female, an eleven-year-old, and a fifteen-year-old. The zoo's veterinarian concluded that heatstroke was the likely cause, citing dehydration and multiple organ failure observed in the animals.
The lion enclosure, which normally allows visitors to ride through in zebra-patterned safari buses, has been closed to the public until further notice. The zoo is intensifying its heat mitigation efforts, including sprinkling water, improving ventilation, and installing spot air conditioners. The spokesperson noted that while lions are generally heat-tolerant, the humidity in Japan presents a different challenge than the dry heat of their native African habitats.
Japan's brutal summer
Japan has been experiencing one of its hottest summers on record, with temperatures in some areas reaching 40°C, a level that has earned the new designation of "cruelly hot day." The heat has led to thousands of hospitalisations; between 20 and 26 July alone, nearly 18,600 people were taken to hospital with heatstroke, and 45 were pronounced dead on arrival, according to the Fire and Disaster Management Agency.
The sudden onset of heat after the rainy season ended in late July has caught many off guard. The zoo spokesperson said the heat "arrived suddenly" this year, making it harder for both animals and humans to adapt.
Animal rights group PETA has criticised the zoo's role, stating that 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." The group argues that zoos exist to display animals for profit rather than to prioritise animal welfare, a claim the zoo has not directly addressed.
Japan records about 1,300 heat-related deaths annually and aims to halve that number by 2030. Scientists say human-induced climate change is increasing the frequency and intensity of extreme heat events in Japan and across the globe. The country's highest recorded temperature of 41.8°C was registered in Isesaki, north of Tokyo, in August 2025.
Authorities have already adjusted the timing of several cultural and sporting events due to the heat, including the World Cosplay Summit in Nagoya, which held its final summer edition last weekend. As Europe also faces rising temperatures, the plight of these lions serves as a stark reminder of the challenges extreme heat poses to both wildlife and human communities.
