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 ghost glass frog in the Chocó rainforest, Ecuador in November 2020. The marbled swirling “hypnotising” eyes are thought to be helpful in attracting a mate. (Photo by David Weiller/WENN)

In this June 20, 2014, file photo, lobsters are processed at the Sea Hag Seafood plant in St. George, Maine. More and more American and Canadian-caught lobsters have been turning up at fancy restaurants in China, marketed as “Boston lobster”, say Maine-based processors. One processing firm owner says it's now the biggest live lobster important day of the year after Christmas in Europe. (Photo by Robert F. Bukaty/AP Photo)

Wedges of an orange generate enough current and electrical juice – 3.5 volts – to power an LED. The fruit’s citric acid helps electrons flow from galvanized nails to copper wire in this 14-hour exposure. This image was published in September’s Visions of Earth, a trio of photos that appear in each issue of National Geographic. (Photo by Caleb Charland/National Geographic)

Hungarian Puli sheep dog, Fee, jumps over a hurdle during a preview for a pedigree dog show in Dortmund on Thursday April 24, 2008. (Photo by Frank Augstein/AP Photo)

This photo taken on December 2, 2015 shows a lenticular cloud forming as white streaks from airplanes mark the blue sky, in a rare atmospheric phenomena above the town of Gevgelija on December 2, 2015. Lenticular clouds have been regularly confused for UFOs throughout history due to the their smooth, round or oval lens-shaped structure. (Photo by Armend Nimani/AFP Photo)

Animal rights activists from People for the Ethical Treatment of Animals (PETA) stage a “die-in” to mark World Vegan Day in Piccadilly Circus in London, Monday, November 1, 2021. The demonstration sought to draw attention to the suffering and death of animals in the meat, egg and dairy industries. (Photo by David Cliff/AP Photo)

Sasha Muir and Margaret Davidson sit in a car as some of the 30 barbary macaques, known as the Middle Hill Troop after living between the top of Gibraltar rock and the town, show what happens when motorists forget to lock their luggage compartments, as Scotland’s only monkey drive-through section opens at Blair Drummond safari park in Stirling, Scotland on October 8, 2015. (Photo by Andrew Milligan/PA Wire)