A palomino horse's mane is seen against the sky at Spancil Hill horse fair in Spancil Hill, Ireland June 23, 2018. (Photo by Clodagh Kilcoyne/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)

School leavers celebrate their graduation in Moscow's Red Square in Moscow, Russia on June 20, 2019. (Photo by Artyom Geodakyan/TASS)

A camel performs during a “dance competition” held during the Pushkar Camel Fair in Pushkar, in the western state of Rajasthan, on November 5, 2019. Thousands of livestock traders from the region come to the traditional camel fair where livestock, mainly camels, are traded. The annual camel and livestock fair is one of the world's largest camel fairs. (Photo by Himanshu Sharma/AFP Photo)

A woman holds her inhaler and leans on another person after being sprayed with mace by police officers during a protest near the Minneapolis Police third precinct after a white police officer was caught on a bystander's video pressing his knee into the neck of African-American man George Floyd, who later died at a hospital, in Minneapolis, Minnesota, U.S. May 27, 2020. (Photo by Eric Miller/Reuters)

Greyhounds resume racing behind closed doors on June 01, 2020 in Perry Barr, England. Greyhound racing across England is returning as restrictions on sporting events are relaxed during the coronavirus pandemic. (Photo by Clive Mason/Getty Images)

A man wearing a protective face mask walks past traditional large puppet figures called “Ondel-ondel”, also donning face masks and displayed along a sidewalk of a main road, as coronavirus disease (COVID-19) cases surge in Jakarta, Indonesia, June 30, 2021. (Photo by Willy Kurniawan/Reuters)

Made Mohon, the operation manager of Sangeh Monkey Forest, feeds macaques with donated peanuts during a feeding time at the popular tourist attraction site in Sangeh, Bali Island, Indonesia, Wednesday, September 1, 2021. (Photo by Firdia Lisnawati/AP Photo)