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)

A girl jumps over a campfire while celebrating Ivan Kupala Night, a traditional Slavic holiday not far from Kiev on July 6, 2013. During the celebration, originating in pagan times, people plait wreaths, jump over fires, and swim naked. (Photo by Sergei Supinsky/AFP Photo)

The mother (2nd R) of missing firefighter Xue Ning is helped by other family members as she cries outside the venue of a news conference after trying to demand for more information from government officials, following the explosions on Wednesday night at Binhai new district in Tianjin, China, August 15, 2015. (Photo by Jason Lee/Reuters)

Members of the Russian Red Army Choir perform at Water Front Theatre in Beirut September 13, 2014. (Photo by Jamal Saidi/Reuters)

A member of the pro-government “red shirt” movement attacks a Buddhist monk outside the National Anti-Corruption Commission office in Nonthaburi province, on the outskirts of Bangkok March 24, 2014. Members of the movement attacked the monk after he shouted complaints to the group blocking a road near the National Anti-Corruption Commission. (Photo by Chaiwat Subprasom/Reuters)

A woman walks in front of an art installation made of artificial fruits and vegetables during the “Moscow Autumn” festival in central Moscow, September 14, 2015. (Photo by Maxim Zmeyev/Reuters)

A mine detection rat is given banana as a reward after successfully identifying an inactive mine on July 2, 2015 in Siem Reap, Cambodia. The Cambodian Mine Action Center (CMAC) working with the Belgian NGO APOPO has recently begun testing the feasability of using large mine detection rats from Tanzania to help clear fields of mines and unexploded ordnance in one of the most bombed and mined countries in the world. (Photo by Taylor Weidman/Getty Images)

USA's Jourdan Elizabeth Delacruz reacts as she competes in the women's 49kg weightlifting competition during the Tokyo 2020 Olympic Games at the Tokyo International Forum in Tokyo on July 24, 2021. (Photo by Edgard Garrido/Reuters)