Afghan female police cadets are seen during their graduation ceremony at Sivas Police Vocational Center Directorate in Sivas, Turkey on March 13, 2018. (Photo by Serhat Zafer/Anadolu Agency/Getty Images)

Police detain a protester during a demonstration against the recent gang-rape of a woman in a moving car, according to local media, in Kolkata, India May 31, 2016. A woman was kidnapped and gang-raped by at least four men on May 29 in the Salt Lake area of the city and is currently being treated in hopsital, local media reported. (Photo by Rupak De Chowdhuri/Reuters)

A boy flies his kite in a cemetery in the Vila Operaria Favela of Rio de Janeiro, Brazil, July 9, 2016. (Photo by Nacho Doce/Reuters)

A view of one of the dioramas contained inside iron boxes as part of the “S.A.C.R.E.D” installation by Chinese artist Ai Weiwei during a media preview at the cathedral in Cuenca, Spain, July 21, 2016. Ai Weiwei has reproduced scenes of his incarceration for a new art installation, a series of almost life-size dioramas – encased in steel boxes – showing his life in jail. (Photo by Susana Vera/Reuters)

Indian devotees carry their luggage and wade through the flooded water in Varanasi, India, Friday, August 26, 2016. (Photo by Tsering Topgyal/AP Photo)

A Sadhu or a Hindu holy man carrying his pet monkey walks after taking a dip at the confluence of the river Ganges and the Bay of Bengal on the occasion of “Makar Sankranti” festival at Sagar Island, south of Kolkata, India, January 14, 2017. (Photo by Rupak De Chowdhuri/Reuters)

A woman holds newly designed Indonesia Rupiah banknotes after exchanging her old bills at a Bank Indonesia mobile bank in Jakarta, Indonesia December 19, 2016. (Photo by Fatima El-Kareem/Reuters)

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)