The six-months-old female koala cub holds on to the back of zoo keeper Lena at the zoo in Duisburg, Germany, 23 October 2015. The yet unnamed baby weighs 580 grams. (Photo by Roland Weihrauch/EPA)

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)

Britain's Queen Elizabeth boards a train at Kings Cross station in London, in this December 17, 2009 file photo. Queen Elizabeth celebrates her 90th birthday on April 21, 2016. (Photo by Stefan Rousseau/Reuters)

American model Emily Ratajkowski shows off her new swimwear line in the second decade of March 2022. (Photo by emrata/Instagram)

This is the moment a lamb appears to be doing kung fu as it plays with its friends in a field overlooking Kimmeridge Bay in Dorset on April 11, 2022. (Photo by Donna White/Bournemouth News)

Festival-goers take photo inside of Spectra, a seven-story spiral walkway up to a viewing deck, at the Coachella Valley Music and Arts Festival in Indio, California, on April 17, 2022. (Photo by Valerie Macon/AFP Photo)

A falla damaged by yesterday's heavy rains is pictured during the Fallas festival in Valencia on September 2, 2021. In Valencia, yesterday's deluge of water disturbed the organization of the Fallas, the major festival in the region featuring parades of floats and giant cardboard sculptures, postponed from March to September due to the pandemic. (Photo by Jose Jordan/AFP Photo)

A health worker makes a heart with her hands while waiting to take swab samples from people in the Jing' an district of Shanghai on May 31, 2022, as the city prepares to lift more curbs after two months of heavy-handed restrictions. (Photo by Hector Retamal/AFP Photo)