Biggest Sea Creature In The World That We Bet You Didn't Know Before

Oluniyi Akande
Oct 26, 2023 By Oluniyi Akande
Originally Published on Nov 23, 2021
Sperm whale in the ocean.
Age: 3-18
Read time: 7.7 Min

The world of aquatic animals is a vast place filled with magnificent species of animals and plants that are awe-inspiring.

The waters of the earth, be it sea, ocean, or any other water body, are home to a variety of mysterious creatures that attract the curiosity of researchers from all over the world. Furthermore, the world's largest living creature also lives in the oceans.

Various aquatic animals have been discovered by humans over the past centuries. The science of marine biology has recently gained a lot of attention as more and more people are becoming interested in marine life and marine ecosystems present beneath the water surface. Yet, even after a vast amount of research has been carried out by researchers, only a small portion of deep-water life has been revealed.

If you find this fun facts article interesting, you might also enjoy learning about the longest living dog breed and longest toenails, here at Kidadl.

List Of Large Sea Creatures

Through research, humans have discovered a lot of marine species. They range from being the smallest animal on earth to the largest animal on earth. Here are fascinating facts about some of the larger aquatic animal species.

The lion's mane jellyfish is the longest sea creature in the world. The scientific name of this jellyfish is Cyanea capillata. They are generally found in the North Atlantic and Pacific Oceans and have a strong population. Lion's mane jellies have eight groups of tentacles in total, and each of these groups has 70-150 individual tentacles. When stretched, the length of this animal with tentacles can reach up to 120 ft (36.5 m).

The largest toothed sea predator, the sperm whale, is the largest whale with teeth. They prey and feed on other sharks, squids, skates, and other fish species. The length of sperm whales (Physeter macrocephalus) can be around 60 ft (18.2 m), and when they are placed in a straight alignment, they are considered to be as tall as an eight story building. From all of the animals on this planet, these whales have the largest brain with a weight of 20 lb (9 kg). Sperm whales were hunted during the period of the 18th-20th century for the spermaceti found on their heads which can be used to make items such as candles and lamp oils. The sperm whale gets its name from this spermaceti which is a waxy substance.

Another species of a huge marine animal is the whale shark (Rhincodon typus). Whale sharks are recognized to be the largest fish in the ocean. The whale shark is considered a gentle giant that slowly swims through the oceans in search of plankton. If you were to ever encounter a whale shark in the ocean, it might just take a fancy and entertain you. Whale sharks are up to 60 ft (18.2 m) long. The whale shark species is considered an Endangered species as they are constantly hunted.

Another shark species that comes under the category of large aquatic creatures is the basking shark. The scientific name given to the basking shark is Cetorhinus maximus. These sharks are considered to be the second-largest fish in the ocean. The largest of the basking shark species has a length of about 40 ft (12.1 m). Interestingly, the basking shark is also able to weigh around 11,464 lb (5,200 kg). These sharks are also considered to be gentle giants that feed on plankton, larvae, and fish eggs.

The giant squid is the longest cephalopod in the ocean. These squid dwell in the deep oceans and are labeled as elusive by the scientists who continuously search for this species in their natural habitat in order to study them. The giant squid has tentacles for feeding that are able to catch prey from a distance of over 30 ft (9.1 m). This squid species is quite popular amongst the legends of sea monsters as they are likened to the massive Kraken, which is considered the largest sea monster. On average, the length of a giant squid is around 32.8 ft (10 m).

The world's largest ray species is the giant manta ray. The scientific name of the giant manta ray is Mobula birostris. They are also called oceanic manta rays. The giant manta ray feeds on zooplankton. Feeding for this species takes place through the cephalic lobes that are present on their heads. These lobes funnel the water and the plankton into the mouth of the giant manta ray.

They are mainly found in the Atlantic Ocean on the south side coast of South Carolina and around New Jersey in the north of America. Sometimes, they are also known to be found in the Pacific Ocean off the coast of southern California and Hawaii. On the IUCN's Red List, this species is listed as Vulnerable due because they are hunted for their meat and skin, along with climate change, population, and habitat degradation. The average length of the giant manta ray is about 23 ft (7 m) across. They can even measure up to the length of 30 ft (9.1 m) across when they spread their pectoral wings.

The giant oarfish (Regalecidae) is a fish species that has a very odd body shape. These fish are known as sea serpents and dragons but actually, fall under the category of gentle giants. The oarfish is also called a bony fish or a ribbonfish because of its long body shape. It is believed that the oarfish is the longest bony fish in the ocean, with a length of 36 ft (11 m). This fish lives in the deep parts of the ocean.

Any list of ocean giants on earth can never be complete without the mention of the blue whale. The blue whale (Balaenoptera musculus) is the largest sea animal on this planet. They are ocean creatures that are mammalian and give birth to young ones called calves. Being the largest animal in the ocean signifies that the other body parts of blue whales are also large in proportions. This being said, the blue whale has the largest tongue and heart out of all the ocean creatures.

Blue whales have a typical diet consisting of consuming thousands of krill individuals in a day. Krill is a crustacean found in the ocean. When the blue whale wants to feed, it opens up its mouth and takes in a huge amount of water along with the krill. The blue whale presses its tongue downwards to trap the contents in its mouth. The baleen plates situated on the upper jaws of the blue whale then let the water pass through its thin gaps and outside while the krill remain trapped inside that it then eats.

The unfortunate news is that these creatures have been classified as Endangered, and their numbers have declined drastically. We need to protect the remaining number of these organisms now.

Biggest Prehistoric Sea Creature

The field of science has advanced so much that the world's smallest as well as the largest animals that have become extinct or belonged to another period of history can still be studied through their fossils that have remained over time.

Details of the organism from the prehistoric era that is considered to be the biggest ocean animal have been collected and recorded.

In southwestern England, fossilized remains of a gigantic marine reptile have been discovered. This giant marine reptile is known as Ichthyosaur, and it used to live around 200 million years ago. The name 'giant' suits the size of the reptilian animal as it is estimated to have been about 85 ft (26 m) long, which is as big as a blue whale.

Lion's Mane swimming.

Biggest Sea Creatures Caught On Camera

While the animals on land are horoughly documented with videos and images, ocean animals are a little harder to catch on a video or in an image. A video or an image of them is mostly possible when they break through the water surface like dolphins and whales.

Advanced cameras are beneficial for catching these organisms in their natural habitat, but it is still difficult. One instance of an aquatic organism being caught on camera is that of the giant squid.

A few scientists from Japan's National Science Museum had been able to film the giant squid in its natural habitat in 2012.

There have, of course, been others but this is one popular example.

What is the size of the biggest sea creature?

As mentioned earlier, the largest animal of the ocean and on earth is the blue whale. But do we know the actual size of the blue whale? What is the size of the biggest blue whale ever recorded?

The average size of an adult blue whale is about 70-90 ft (21.3-27.4 m) long. Blue whales also weigh around 200,000-300,000 lb (130,000-150,000 kg) on average. It is also noted that the females of this species are slightly bigger in size than the males.

The largest blue whale ever discovered was a female that was 110 ft (33.5 m) long.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for the biggest sea creature, then why not take a look at the longest tapeworm or longest river in Asia.

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Written by Oluniyi Akande

Doctorate specializing in Veterinary Medicine

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Oluniyi AkandeDoctorate specializing in Veterinary Medicine

With an accomplished background as a Veterinarian, SEO content writer, and public speaker, Oluniyi brings a wealth of skills and experience to his work. Holding a Doctor of Veterinary Medicine degree from the University of Ibadan, he provides exceptional consulting services to pet owners, animal farms, and agricultural establishments. Oluniyi's impressive writing career spans over five years, during which he has produced over 5000 high-quality short- and long-form pieces of content. His versatility shines through as he tackles a diverse array of topics, including pets, real estate, sports, games, technology, landscaping, healthcare, cosmetics, personal loans, debt management, construction, and agriculture.

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