Sometimes you're sure you've seen a monster, but your friends say it's just a sturgeon. Or you spotted a shape in the water that looks just like a serpent should look. But sometimes it really is just a log, or a shark's carcass, or Shamu's fin. Look here to find pictures and descriptions of itmes that look like sea monsters or are commonly mistaken for such. But hey, these guys were sea monsters once. The only difference between the animals presented here and, say, the Gloucester Sea Serpent is that these guys have been officially recognized as real. Still, they're pretty cool.
Logs
If you see this sort of thing, consider whether there were recent heavy rains. A rainstorm shoved tons of logs down the River Ness into Loch Ness into 2010, causing many tourists to think they were seeing a bunch of Loch Ness Monsters.

If you see this sort of thing, consider whether there were recent heavy rains. A rainstorm shoved tons of logs down the River Ness into Loch Ness into 2010, causing many tourists to think they were seeing a bunch of Loch Ness Monsters.

Arapaima fish
A diver shares a tank with an adult arapaima fish at an aquarium in Manaus, Brazil. This South American giant is one of the largest freshwater fish in the world. Some reach lengths of more
A diver shares a tank with an adult arapaima fish at an aquarium in Manaus, Brazil. This South American giant is one of the largest freshwater fish in the world. Some reach lengths of more
than 10 feet (3 meters) and weigh upward of 400 pounds (180 kilograms).

Giant Bluefin Tuna
You may find this species of fish freightening, but worry not. This overfished fish is found commonly in Japanese waters, and makes one of the most prized types of sushi available. Because of its cullinary value, a single bluefin tuna can sell for tens of thousands of dollars on the world market.

You may find this species of fish freightening, but worry not. This overfished fish is found commonly in Japanese waters, and makes one of the most prized types of sushi available. Because of its cullinary value, a single bluefin tuna can sell for tens of thousands of dollars on the world market.

Giant Clam
Divers in the Bikini Atoll in the Marshall Islands spotted a giant clam (Tridacna gigas) anchored to a coral reef. In the day, the animal's fleshy mantle—which contains green algae—spreads over its open shell to take in sunlight. The sun feeds the algae, which in turn nourishes the mollusk.

Divers in the Bikini Atoll in the Marshall Islands spotted a giant clam (Tridacna gigas) anchored to a coral reef. In the day, the animal's fleshy mantle—which contains green algae—spreads over its open shell to take in sunlight. The sun feeds the algae, which in turn nourishes the mollusk.

Whale Shark
If anything in the ocean looks like a sea monster, this critter certainly does, This beasty, however, is well documented by science is commonly known as a whale shark, a gentle beast of the ocean which divers often take rides on by grabbing on to its fin. While it is called a "shark", this creature is actually the largest known fish (sharks have cartillage instead of bone).
If anything in the ocean looks like a sea monster, this critter certainly does, This beasty, however, is well documented by science is commonly known as a whale shark, a gentle beast of the ocean which divers often take rides on by grabbing on to its fin. While it is called a "shark", this creature is actually the largest known fish (sharks have cartillage instead of bone).
Barnacle-covered log
This 30-foot barnacle-covered log washed up on the shores of Llangrannog, Wales. One resident said, "With all the tendrils moving around the whole thing looks like a giant sea monster."
This 30-foot barnacle-covered log washed up on the shores of Llangrannog, Wales. One resident said, "With all the tendrils moving around the whole thing looks like a giant sea monster."