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)

Philadelphia Phillies Ben Francisco reacts after being hit in the head with a pitch by Cincinnati Reds Logan Ondrusek during the MLB National League Division Series baseball playoffs in Philadelphia, Pennsylvania, United States in this October 8, 2010 file photo. (Photo by Tim Shaffer/Reuters)

Indian commuters wade through floodwaters during the continuous rain shower in Calcutta, India, July 10, 2015. A monsoon shower hit the city and disrupted daily life. The Indian monsoon, takes place between May and September. (Photo by Piyal Adhikary/EPA)

A man carries a blood stained stretcher in a site hit by what activists said were airstrikes carried out by the Russian air force in the town of Douma, eastern Ghouta in Damascus, Syria January 10, 2016. (Photo by Bassam Khabieh/Reuters)

Visitors make snowmen beside a pool at a hot spring in Hangzhou, in China's eastern Zhejiang province on January 26, 2018. China's central and eastern regions have been hit by heavy snowfalls in recent days, causing disruptions to flight and train schedules. (Photo by AFP Photo/China Stringer Network)

One happy reveller smiled and gave a thumbs up to the camera in Newcastle, United Kingdom after receiving their A Level results on Tuesday, August 10, 2021. Students hit the town across the country, downing cocktails and letting their hair down after two years of studying during the pandemic. (Photo by Newcastle New Projects)

Health workers screen residents for COVID-19 symptoms at Dharavi, one of Asia's biggest slums, in Mumbai, India, Monday, August 3, 2020. India is the third hardest-hit country by the pandemic in the world after the United States and Brazil. (Photo by Rafiq Maqbool/AP Photo)

A girl feeds the new-born kitten as the family, living in tent city, adopted two kittens, found under the rubble, after 7.7 and 7.6 magnitude earthquakes hit in Hatay, Turkiye on March 15, 2023. (Photo by Sergen Sezgin/Anadolu Agency via Getty Images)