Alex Mustard / Banded jawfish (Opistognathus macrognathus) male incubating eggs in mouth, which are at a late stage of development and will soon be ready for release. West Palm Beach, Gulf Stream, West Atlantic Ocea...

Alex Mustard / Sharpnose puffer (Canthigaster rostrata) portrait with the eyes standing out against a dark background, East End, Grand Cayman, Cayman Island, British West Indies, Caribbean Sea.

Bernard Castelein / Southern plains grey langur ( Semnopithecus entellus / Presbytis entellus) close up face profile, Sawai Modhopur, Rajasthan, India

Alex Hyde / Regal jumping spider (Phidippus regius) male originating from North America. Captive.

Bernard Castelein / Banded Demoiselle (Calopteryx splendens) head portrait, at rest on leaf, Brasschaat, Belgium

Tim Laman / Head portrait of a Wild Western / Sunda tarsier (Tarsius bancanus) on tree trunk at night. Danum Valley Conservation Area, Borneo, Sabah, Malaysia

Edwin Giesbers / Shed skin of grass snake {Natrix natrix} on lilypad, Netherlands.

Claudio Contreras / Grey whale (Eschrichtius robustus) eye, Magdalena Bay, Baja California, Mexico, February. Winner in the Ocean Views category of the 2018 Nature's Best Winland Smith Rice Awards.

Franco Banfi / Sperm whale (Physeter macrocephalus) eye detail, Dominica, Caribbean Sea, Atlantic Ocean, Vulnerable.

Doc White / Gray whale (Eschrichtius robustus) Scammons Lagoon, Baja California, Mexico

Doc White / Gray whale (Eschrichtius robustus) eye up close, Scammons Lagoon, Baja California, Mexico

Jordi Chias / Short-finned pilot whale (Globicephala macrorhynchus) at surface, showing eye, South Tenerife, Canary Islands, Atlantic Ocean, July