Fingal's Cave, the hexagonal mouth of the cave with the heather-covered slopes of Mull behind, Argyll and Bute, Scotland, United Kingdom, Europe

Twenty four foot saltwater crocodile (Crocodilus porosus), Hartleys Creek, Queensland, Australia, Pacific

Coral Grouper (Cephalopholis miniata) being cleaned by a BruunÌs Cleaning Partner Shrimp (Urocaridella aontonbruunii) this incredible gaping action allows the shrimp uninhibited access to the mouth and gills. Red Sea.

Coral Grouper (Cephalopholis miniata) being cleaned by a BruunÃs Cleaning Partner Shrimp (Urocaridella aontonbruunii) this incredible gaping action allows the shrimp uninhibited access to the mouth and gills.Red Sea.

Coral Grouper (Cephalopholis miniata) being cleaned by a BruunÌs Cleaning Partner Shrimp (Urocaridella aontonbruunii) this incredible gaping action allows the shrimp uninhibited access to the mouth and gills. Red Sea.

Manta ray, Manta birostris, feeding at night, Kailua-Kona, Big Island, Hawaii

Split shot of a Basking Shark (Cetorinus Maximus) in Gunna Sound, Isle of Colll, Scotland. It's mouth is gaping as it feeds. Clouds are lit with the setting sun in the background.

Yawning Hippopotamus (Hippopotamus Amphibius) At Serengeti National Park, Tanzania

A Brown Bear (ursus arctos) about to catch a salmon in it's mouth at the top of Brooks Falls, Alaska. The fish is only a few inches away from its gaping jaws. Shot with a Nikon D800 in July 2015, Alaska, United States of America

A brown bear (Ursus arctos) about to catch a salmon in its mouth at the top of Brooks Falls, Alaska. The fish is only a few inches away from its gaping jaws. Shot with a Nikon D800 in Alaska; Kodiak, Alaska, United States of America

Hawaii, Big Island, Kona, Whale Shark (Rhiniodon typus) with mouth wide open