What is the longest animal in the world?

Wiggling its way through our soil and sand, slimy and sticky, there is a worm so long that it defies expectations – and all other living creatures.

The bootlace worm grows up to 200 times longer than an ordinary earthworm.
The bootlace worm grows up to 200 times longer than an ordinary earthworm.  © 123RF/buhta

You might think that the longest animal in the world is a huge beast, buff and brawny.

But you'd be surprised to know who beats all competition by a mile!

The animal world record holder for being the longest living creature is a sly sucker that burrows deep beneath the earth's surface.

Top 10 grumpy cat breeds
Cat Guide Top 10 grumpy cat breeds

It's time to dive into the wonderful world of the bootlace worm, a strange creature so bizarre and extraordinary that it has won itself a world record. Let's take a look!

What's the world's longest animal?

The bootlace worm is one of the most extraordinary worms in the world.
The bootlace worm is one of the most extraordinary worms in the world.  © IMAGO/agefotostock

The bootlace worm can be found primarily in the North Atlantic Ocean, as well as the North Sea off the coast of the UK and Germany. It's remarkable, capable of growing more than 180 feet long, making the bootlace worm the longest living animal in the world.

Having washed ashore following an extremely severe storm at St. Andrews in Fife, UK, a record was born in 1864. Seeing as the specimen, measured at 180 feet in length, has never been beat, it is recognized by Guinness World Records as the longest "solitary animal" in the world, a record it has held for 159 years as of writing.

The bootlace worm is a species of ribbon worm and is highly toxic to a variety of animals (though, not humans, so no worries there). While long, they are only generally about 0.2 to 0.4 of an inch in diameter, and can be recognized by their brown stripes.

Elephant takes a stroll through traffic in wild Montana footage!
Animals Elephant takes a stroll through traffic in wild Montana footage!

The world's longest animal, the bootlace worm, feeds off of crabs and cockroaches, and lives both underwater and underground. They are generally found off the coastlines around northern Europe and Scandinavia, and are some of the weirdest worms out there.

Why is the longest animal so lengthy?

Bootlace worms feel at home hidden in the stones and algae, or in the sand, of a brackish beach, feeding off of small shrimps, worms, and other tiny sea creatures. They are carnivorous, using extremely strong toxins to hunt and defend themselves when threatened - or when they just want a good feed.

While these toxins can paralyze and kill crustaceans, even small crabs, it is unknown what the impact of the substance is on mammals. What we can say, however, is that it is known to be completely harmless to humans. Sure, it could be unpleasant, but it won't kill you.

The bootlace worm is so long, though, because it does not have a barbed proboscis which it can use to attack prey. Instead, it must absorb nutrients directly through the skin – and the more surface area, the greater the efficiency.

The blue whale is one of the world's longest animals.
The blue whale is one of the world's longest animals.  © 123RF/izanbar

What other animals are long?

Many big animals are also long, but not all long animals are big. While the bootlace worm is the longest animal to (as far as we know) ever slime its way across our gorgeous green globe, it's not the biggest. The record for biggest animal, instead, belongs to the blue whale - which also has a shot at being one of the longest living things on Earth.

Here are a few other contenders for longest animals in the world:

  • Blue whale: Approximately 80–90 feet long, records of over 100 feet
  • Whale shark: Approximately 25–35 feet long, record of 61.7 feet
  • Giant squid: Approximately 7–10 feet long (just the body), record of over 16 feet, possibly longer, if individual tentacles added up even more impressive
  • Box jellyfish: Approximately 12 inch diameter, tentacles of more than 10 feet in length (and numerous)
  • Sperm whale: Approximately 60 feet in length

Despite how long the likes of the blue whale and giant squid can get, nothing will ever beat the bootlace worm! At more than 180 feet in length, this is certainly one worm to write home about.

Cover photo: 123RF/buhta

More on Animal World Records: