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)

An Afghan Army soldier secures the hill overlooking the Kart-e Sakhi mosque in Kabul, Afghanistan, Wednesday, March 20, 2013. Thousands of Afghans will celebrate Nowruz on Thursday, March 21, 2013 to mark the first day of spring and the beginning of the year on the Iranian calendar. (Photo by Ahmad Jamshid/AP Photo)

A man waits for Queen Beatrix's abdication ceremony outside the Royal Palace in Amsterdam April 30, 2013. The Netherlands is celebrating Queen's Day on Tuesday, which will also mark the abdication of Queen Beatrix and the investiture of her eldest son Willem-Alexander. (Photo by Paul Vreeker/Reuters)

North Koreans perform during the “Arirang” Mass Games at the May Day Stadium in Pyongyang, as part of celebrations ahead of the 60th anniversary marking the end of the 1950-53 Korean War, in this photo taken by Kyodo July 22, 2013. (Photo by KYODO)

Residents make decorations mosque-shaped lamps to enliven the holy month of Ramadan in Pekanbaru, Riau Province on April 28, 2022. Muslims throughout the world are marking the month of Ramadan, the holiest month in the Islamic calendar, during which devotees fast from dawn till dusk. (Photo by Afrianto Silalahi/ZUMA Press Wire/Rex Features/Shutterstock)

People watch Russian heavy weapons at Tverskaya street during the rehearsal of the Victory Day parade in Moscow, Russia, 04 May 2022. Victory Day is held annually on 09 May and marks the defeat of Nazi Germany in 1945. (Photo by Yuri Kochetkov/EPA/EFE)

Animal rights activists from People for the Ethical Treatment of Animals (PETA) stage a “die-in” to mark World Vegan Day in Piccadilly Circus in London, Monday, November 1, 2021. The demonstration sought to draw attention to the suffering and death of animals in the meat, egg and dairy industries. (Photo by David Cliff/AP Photo)

Dancers take part in a parade to mark the opening of the annual Bali Art Festival on a main road in Denpasar, Bali, Indonesia, 12 June 2022. The Bali Art Festival runs from 12 June to 10 July 2022 and features hundreds of performers. (Photo by Made Nagi/EPA/EFE)