With its huge eyes, comical name and diminutive size, Mark R. Smith’s image of a baby Hawaiian bobtail squid can’t help but raise a smile. A curiously endearing creature, the cephalopod is just 1.5cm across, its mantle cavity bearing more than a passing resemblance to a rather natty shower cap. But it is also a beautiful example of symbiosis – nature’s version of “I’ll scratch your back if you scratch mine” – for on the underside of the squid is a light organ which houses bioluminescent bacteria. The squid offers the bacteria protection and food, while the bacteria emit a glow – a handy trait that the squid uses to offset its silhouette, helping it to evade predators in the depths below. Mark R. Smith’s entry combines several images of a Hawaiian bobtail squid with different focus lengths to create a final picture with greater depth of field than normal. (Photo by Mark R. Smith/Wellcome Images/Macroscopic Solutions)

Pokot men carry a part of a carcass of a bull killed by a young man during an initiation ceremony in Baringo County, Kenya, January 20, 2016. Far from the bustling city of Nairobi, in an isolated corner of Kenya's Rift Valley, young men from the Pokot community spear a bull in a ceremony called Sapana that takes them into adulthood. (Photo by Siegfried Modola/Reuters)

An Iraqi woman, dressed as Santa Claus, rides her bicycle amid the spread of the coronavirus in the old city of Mosul, Iraq, December 18, 2020. (Photo by Abdullah Rashid/Reuters)

Bodybuilders pose on stage during the Mr.001 bodybuilding competition in Mombasa, Kenya, on December 11, 2021. This bodybuilding competition was created by a former bodybuilder and its the first one to happen in the coastal city since 2015. The name comes from Mombasa's county code and currently is considered one of the biggest in East and Central Africa. The first edition brought over 200 participants from Kenya, Uganda, Tanzania, Nigeria, South Africa and Pakistan who competed in different categories including physique, bikini and figure. (Photo by Patrick Meinhardt/AFP Photo)

Dogs are seen at the 2021 Pawlidays celebration at Sofitel Hotel Los Angeles on December 18, 2021 in Los Angeles, California. (Photo by Emma McIntyre/Getty Images)

The first legal wedding ceremony in history was performed in a hot tub when Leslie Davis, 23, and Richard Bustardo, 29, got married during the Backyard Living Show in Los Angeles, March 26, 1975. The ceremony was held in a five-foot hot tub, with the bride wearing a bikini and the groom attired in swimming trunks and top hat. In background is best man Arnold Holland and bridesmaid Bonnie Heckenbach, who joined the couple in the same hot tub. Officiating is Betty Jane Shaw, left. (Photo by Harold Filan/AP Photo)

Actress Marney McQueen attends the 2025 ARIA Awards at Hordern Pavilion at Hordern Pavilion on November 19, 2025 in Sydney, Australia. (Photo by Hanna Lassen/Getty Images)

Communist supporters hold portraits of Soviet leader Josef Stalin as they queue to lay flowers at the grave of Stalin to mark the 139th anniversary of his birth, in Moscow's Red Square, Russia, Friday, December 21, 2018. (Photo by Pavel Golovkin/AP Photo)