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)

In this photograph taken on February 18, 2016, Pakistani children ride on swings in the predominantly Pashtun Korangi District of Karachi. In a rundown district of Karachi, Rabia balks at a neighbour's proposal to vaccinate her children, demonstrating one of the biggest hurdles to eradicating polio in Pakistan by the end of the year: confused and frightened parents. (Photo by Asif Hassan/AFP Photo)

An alpaca is seen near the Inca citadel of Machu Picchu in Cusco December 2, 2014. Machu Picchu, a UNESCO World Heritage Site, is Peru's top tourist attraction, with the government limiting tourists to 2,500 per day due to safety reasons and concerns over the preservation of the ruins. (Photo by Enrique Castro-Mendivil/Reuters)

United States' Abby Dahlkemper, left, and Netherlands' Lieke Martens fall while fighting for the ball during a women's quarterfinal soccer match at the 2020 Summer Olympics, Friday, July 30, 2021, in Yokohama, Japan. (Photo by Silvia Izquierdo/AP Photo)

The aerial view shows three uprooted trees at a road near Hildesheim, Germany Friday, October 6, 2017. Seven people died Thursday as high winds knocked over trees and caused widespread travel chaos in northern Germany. (Photo by Julian Stratenschulte/DPA via AP Photo)

A person dressed up as Spider-Man sits next to the cabs as taxi drivers hold a protest against taxi-hailing apps such as Uber, Cabify and Didi at Angel de la Independencia monument, in Mexico City, Mexico, October 12, 2020. (Photo by Edgard Garrido/Reuters)

UK's Love Island favourite Maura Higgins, 29, was seen wearing a short satin dress as she left Amazonico Restaurant in Mayfair, central London on October 28, 2020. (Photo by Splash News and Pictures)

Fans react as they watch HBO's “Game of Thrones” series finale at a viewing party at Brennan's bar in Marina del Rey, California, May 19, 2019. (Photo by Robyn Beck/AFP Photo)