1. Harbor porpoise
   Great white shark
2. Thresher shark
   Narwhal

Great white sharks typically reach lengths of 16 feet, but some have hit nearly 20 feet long. Unreliable reports in the past have suggested some specimens have reached lengths of 37 feet or so, but those are pretty dubious.

1. Andean condor
   Peregrine falcon
2. Turkey vulture
   Goshawk

Andean condors have a wingspan of over 10 feet and weigh nearly 30 pounds. That may seem small, but consider that a bald eagle weighs only about 14 pounds, and you get an idea of just how big an Andean condor truly is.

1. Beluga whale
   Orca whale
2. Irrawaddy dolphin
   Bottlenose dolphin

Bottlenose dolphins can grow to be about 13 feet in length and are known for their exceptional intelligence. Some dolphins have been observed using tools in the wild, and they can recognize the whistles of other dolphins even after 20 years apart.

1. Water horse
   Stoat
2. Hippopotamus
   Black rhino

Male hippos continue to grow throughout their lives and can reach lengths of 17 feet. Despite their size, they're quite fast in the water and even on land. They're also an invasive species in Colombia thanks to drug lord Pablo Escobar, who smuggled four of them into the country in the 1980s.

1. Siberian tiger
   Clouded leopard
2. Cheetah
   Mountain lion

Siberian tigers can grow to a length of over 10 feet to the tip of their tails. They tend to feed mostly on deer-like species that live in Russia and China but will hunt smaller prey, like rabbits, and larger prey, like bears, on occasion.

1. Cassowary
   Emu
2. Ostrich
   Kestrel

Ostriches can reach heights of over 9 feet and weigh over 300 pounds, making them the largest birds in the world. There's a common myth that ostriches foolishly bury their heads in the sand in a vain effort to hide from danger. This isn't true and probably is the result of someone watching one digging in the sand for pebbles.

1. Green anaconda
   Black mamba
2. Taipan
   Rat snake

Green anacondas can grow to 16 or 17 feet in length, but they seem to be subject to wild rumor more than most snake species. As such, there are numerous stories of snakes reaching lengths of 20 to 30 feet and a weight of over 500 pounds, but none of them have ever been scientifically confirmed.

1. Nile monitor
   Gharial
2. Caiman
   American alligator

American alligators can reach a length of over 15 feet. They're one of the only reptiles ever observed using tools. In this case, they've been documented using lures to attract birds.

1. King cobra
   Burmese python
2. Garter snake
   Water moccasin

The Burmese python averages about 16 feet in length but can exceed 20 feet on occasion. It's believed that Hurricane Andrew destroyed a python breeding facility in 1992, and the escaped snakes set up a viable population in Florida.

1. Cougar
   Lion
2. Liger
   Lynx

Ligers are the offspring of tigers and lions, specifically a male lion and a female tiger. The offspring end up being larger than either parent, coming in at close to 12 feet in length. Breeding of ligers isn't all that common. There are about 30 of them in the United States.

1. Blue whale
   Right whale
2. Humpback whale
   Sperm whale

Blue whales are massive beyond belief, larger than any dinosaur that ever walked the Earth or swam in its oceans. They can grow to 98 feet in length and weigh in at 190 metric tons. Whaling severely depleted their numbers, they have been slowly climbing back up.

1. Morgan horse
   Appaloosa
2. Shire horse
   Thoroughbred

Shire horses are the largest horses in the world and measured to the withers, the tallest on record clocked in at just over 7 feet tall. With its head raised, it would have been looking down at pretty much anyone in the NBA.

1. Saltwater crocodile
   Komodo dragon
2. Gharial
   Rock iguana

Saltwater crocodiles are massive! Males reach nearly 20 feet in length and can weigh 2,000 pounds. Saltwater crocodiles have been confirmed as having the strongest bite force in the world.

1. Black bear
   Sloth bear
2. Grizzly bear
   Panda bear

A grizzly bear can reach heights of about 9 feet, 8 inches when they stand upright. Their claws can grow to be about 4 inches in length. As a point of reference, that's about the size of human fingers.

1. Sand shark
   Greenland shark
2. Whale shark
   Nurse shark

The largest whale shark ever recorded was 62 feet in length. That size is impressive when you consider whale sharks are filter feeders, meaning they're not going to bite you like a great white shark. Instead, they feed on plankton, dozens of pounds of it per day.

1. Alligator gar
   Hammerhead shark
2. Blue marlin
   Largetooth sawfish

Largetooth sawfish are typically about 8 feet long but can also reach lengths of around 23 feet. The saw is used to stir up the bottom of the sea to disturb potential prey and also to strike at fish they're hunting. Unfortunately, they also have a bad habit of getting stuck in fishing nets.

1. Bluefin tuna
   Sunfish
2. White sturgeon
   Barracuda

White sturgeon can each about 20 feet in length and weigh over 1,700 pounds. Generally, they're much smaller, coming in at about 5 or 6 feet in length. Caviar fishing nearly drove them to extinction before they bounced back.

1. Sei whale
   Fin whale
2. Sperm whale
   Gray whale

Fin whales can reach a length of 85 feet and weigh upwards of 82 short tons. This makes the fact that they can swim at speeds of around 25 miles per hour all the more impressive.

1. Tapir
   Gaur
2. White rhinos
   Asian elephants

Asian elephants typically reach a height of about 9 feet at the shoulder. The largest on record was over 11 feet high and over 24 feet long. It was shot back in 1924. There have been unconfirmed reports of even larger elephants, though.

1. Alpaca
   Giraffe
2. Llama
   Cassowary

Giraffes typically reach heights of about 18 feet. Back in the days of Ancient Greece and Rome, they were called camelopardalis because people thought they were a hybrid of camels and leopards.

1. White rhino
   Wild boar
2. Hippopotamus
   Indian elephant

White rhinos are the largest species of rhino in the world. Males have a body length of about 13 feet. That comes with a weight of about 5,000 pounds, making these animals extremely massive.

1. Blue squid
   Box jellyfish
2. Candiru
   Lion's mane Jellyfish

The lion's mane jellyfish is the largest species of jellyfish in the world. The bell is over 7 feet in diameter, but it's their massive tangle of tentacles that really gives them their size, growing to as much as 120 feet in length!

1. Whipworm
   Sea anemone
2. Sea cucumber
   Bootlace worm

Bootlace worms can grow to a staggering 180 feet in length. When they're threatened, they secrete a mucus that has a neurotoxin in it able to kill small predators. It also smells like sewage, so that's fun.

1. Moon jelly
   Portuguese man o' war
2. Blue jellyfish
   Spotted jellyfish

The Portuguese man o' war typically has tentacles that are over 30 feet long but sometimes reach lengths of up to 98 feet. Their tentacles can sting, even after they've been torn off the main body or if the jellyfish has died.

1. Sloth bear
   Sun bear
2. Polar bear
   Panda bear

Adult male polar bears can reach heights of nearly 10 feet when they rear up on their hind legs. One of the largest-ever specimens was just over 11 feet tall. At a weight of over 1,500 pounds, they are the largest bears in the world and the largest predators in Canada.

1. Tapeworm
   Land leech
2. Fluke worm
   Horsehair worm

Tapeworms take up residence inside of you and feed on the nutrients you ingest, growing to a length of up to over 80 feet in length. Try to imagine something like that living inside of you.

1. Australian brown worm
   Giant Gippsland earthworm
2. Segmented earthworm
   African giant earthworm

The African giant earthworm is usually only about 6 feet in length which, if we're being honest, is still pretty dramatic for a worm. The largest ever found was 22 feet long but, even at that dramatic size, they're so thin, they only weigh a few pounds.

1. Water moccasin
   Snake sea cucumber
2. Feather fish
   Brittle star

The snake sea cucumber looks a bit like a log of decaying plant matter, but it can grow to be about 10 feet long. It has tiny nubs called spicules all over its body, and it uses them like feet, but they're also extremely sticky and hard to remove from anything, including a diver's wet suit.

1. Japanese spider crab
   Horseshoe crab
2. King crab
   Dungeness crab

Japanese spider crabs can reach 18 feet from claw to claw, making them the largest crustacean in the sea. They're also considered a delicacy, though the fishing industry for them is relatively small. Overfishing has caused a population decline, and these days, most crabs tend to be relatively small.

1. Caribou
   Elk
2. Moose
   White-tailed deer

Moose stand about 6 feet, 9 inches tall at the shoulder with a nearly 6-foot span across the antlers that also add height. Their body length is around 10 feet long. In 1900, they tried to establish a population in New Zealand that seemed not to work. However, hair and antlers have been discovered as recently as 2002.

1. Giant oarfish
   Skipjack tuna
2. Pacific salmon
   Sunfish

Giant oarfish can grow over 30 feet long, which makes them look a lot like ribbons. They can beach themselves on occasion and will also come to the surface when they're sick. It's thought that maybe they're the source of old sea serpent tales.

1. Colossal squid
   Vampire squid
2. Blue-ringed octopus
   Nautilus

The colossal squid is likely the largest invertebrate in the world, but getting a feel for the average size is hard since so few specimens have ever been discovered. Most estimates put their size at up to about 46 feet in length, however.

1. Oarfish
   Angelfish
2. Giant oceanic manta ray
   Barracuda

Giant oceanic manta rays can grow to have a wingspan of over 20 feet across and, in at least one case, an Atlantic manta ray was recorded as having a wingspan of 30 feet. Thanks to the fact they can also swim over 20 miles an hour, there are very few animals in the sea that hunt these giant creatures.

1. Seagull
   Wandering albatross
2. Andean condor
   Grey pelican

They call the wandering albatross for a reason. Some birds can cover as much as 75,000 miles in a year. They have the largest wingspan of any living bird and can reach nearly 12 feet across.

1. Llama
   Alpaca
2. Camel
   Thoroughbred

A full-grown camel is over 7 feet tall to the top of its hump, and some species can weigh over 2,000 pounds. Due to the nature of the habitat in which they live — often arid or desert areas — camels can go for up to 10 days without having to drink anything.

1. Sea otter
   Narwhal
2. Walrus
   Elephant seal

Elephant seals are absolutely massive and not only can males reach 20 feet on rare occasions, but they can also exceed 8,000 pounds, which is about 4 tons. Males can be nearly 10 times the size of females.

1. Skipjack tuna
   Ocean sunfish
2. Mahi-mahi
   Dogfish

Ocean sunfish look a bit like a head that can swim and are deceptively large. Devoid of something for comparison it's hard to tell that these fish can grow to over 10 feet in height and 14 feet across the fins. They can also weight over 5,000 lbs.

1. Nautilus
   Giant squid
2. Big red jellyfish
   Giant Pacific octopus

The giant Pacific octopus made it into the Guinness Book of World Records as the largest octopus in the world with one having a 32-foot arm span. You probably wouldn't want a hug from that guy.

1. Galapagos tortoise
   Leatherback sea turtle
2. Red-eared slider
   Box tortoise

Leatherback sea turtles are the largest turtles in the world. Their average length is only about 5 and a half feet, which is dramatic for a turtle but not super huge. That said, some specimens have hit lengths of about 7 feet, 2 inches, which is definitely longer than your average person.

1. Snakefish
   European conger eel
2. Alligator gar
   Reef fish

European conger eels are the largest eels in the world and can reach a maximum length of over 9 feet. They can live in the frosty waters near Norway. When they reproduce, females will lay millions of eggs, though only a few will make it to maturity.