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)

People walk along the Neva River at sunset in St.Petersburg, Russia, Tuesday, December 6, 2016. The temperature in St.Petersburg is –9C ( 15.8 °F). (Photo by Dmitri Lovetsky/AP Photo)

An aircraft passes over houses at it lands at Heathrow Airport near London, Britain, December 11, 2015. Picture taken December 11, 2015. (Photo by Neil Hall/Reuters)

Russian cosmonaut Alexander Skvortsov, Expedition 40 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) in support of science and maintenance on the International Space Station on August 18, 2014. During the five-hour, 11-minute spacewalk, Skvortsov and cosmonaut Oleg Artemyev (out of frame) deployed a small science satellite, retrieved and installed experiment packages and inspected components on the exterior of the orbital laboratory. (Photo by NASA)

A statue of former U.S. President Donald Trump is pictured at the Conservative Political Action Conference (CPAC) in Orlando, Florida, U.S. February 26, 2021. (Photo by Octavio Jones/Reuters)

Dressed in folk costumes, young women decorate a tree with painted Easter eggs in Dombrad, Hungary, Monday, April 5, 2021. (Photo by Attila Balazs/MTI via AP Photo)

American supermodel Bella Hadid (R) holds onto her friend's leg for dear life in the second decade of January 2023. (Photo by bellahadid/Instagram)

Ukrainian service man Oleksandr of 24th brigade stands guard at his position in the trenches at the frontline, amid Russia?s attack on Ukraine near Niu York, Donetsk region, Ukraine on April 4, 2023. (Photo by Kai Pfaffenbach/Reuters)