An elephant cools off at a zoo in Karachi, Pakistan, 31 March 2021. Caretakers at Karachi's zoo were working to keep animals cool during a​ heatwave affecting southern Pakistan. (Photo by Shahzaib Akber/EPA/EFE)

A ring-tailed lemur sunbakes at Melbourne Zoo in Melbourne, Victoria, Australia on December 21 2016. (Photo by Julian Smith/EPA)

The nearly four-week-old Tapir cub bathes on June 28, 2016 in Gondwanaland at the zoo in Leipzig, Saxony. (Photo by Jan Woitas/DPA)

Gelada baboons (Theropithecus gelada) play in their enclosure at the Zoo in Zurich, Switzerland, Wednesday, May 15, 2013. (Photo by Steffen Schmidt/Keystone/AP Photo)

A Chimpanzee is seen with funny expressions at Hanover Zoo on September 27, 2013 in Hanover, Germany. (Photo by Barcroft Media)

Giant pandas enjoy food around a table at Chongqing Zoo, Chongqing, China on May 21, 2023. (Photo by Rex Features/Shutterstock)

Teeming with images of spectacular underwater scenes from around the world, Call of the Blue is the culmination of a five-year project by the photographer and ocean conservationist Philip Hamilton. This groundbreaking book includes contributions from acclaimed scientists and ocean “guardians”, who reveal what drove them to answer the call of the blue. (Photo by Philip Hamilton/The Guardian)