The One Era When Blue Whales Weren’t the Largest Creatures

Added: 2026-05-09

[00:00:00]This is the blue whale, the heaviest creature that has ever existed on Earth.

[00:00:05]A living symbol of the biological limit where nature almost touches the ceiling of what it can create.

[00:00:11]But what if I told you that there was once a time in history when blue whales were not the absolute giants? If there was another creature that was not a whale, not even a mammal, but large enough to challenge that position. An ancient creature from the deep ocean. A strange experiment of evolution that today only a few scattered bones remain.

[00:00:33]How big was it? And what caused it to disappear completely from this planet?

[00:00:39]Is the 200-ton limit that we believe in really the limit or just the limit of what we have found?

[00:00:46]This story will take you back to a time when all familiar rules were broken.

[00:00:50]Blue whales and physical limits.

[00:00:53]Blue whales are more than 25 m long and can weigh more than 200 tons. And that number is not only impressive, but also has a deeper meaning. It represents the ultimate boundary of biology because it is not that evolution does not want to create something bigger, but it cannot.

[00:01:11]When a body becomes too large, its own weight will begin to become the enemy.

[00:01:16]The bone structure can no longer withstand the pressure. The circulatory system has to work too hard and eventually the body will collapse under its own mass. So blue whales exist right on the edge of what is possible. As a creature optimized to the maximum to exist within the physical limits of this world.

[00:01:36]And for a long time humans believed that it was an insurmountable peak until a small but surprising discovery appeared.

[00:01:43]The appearance of Ichthyotitan.

[00:01:47]Everything started to change when scientists discovered a giant jawbone belonging to a previously unknown creature. They named it Ichthyotitan.

[00:01:56]And from the beginning the name said it all. A giant sea monster. But what makes this discovery special is not only its size, but also its nature.

[00:02:07]This creature is not a whale, but a marine reptile, which means that at some point in history not only mammals, but also reptiles reached such a giant size.

[00:02:17]And for the first time we have a real opponent who can question whether blue whales are really the largest creatures that have ever existed. Size in comparison and controversy.

[00:02:28]When it comes to the largest creature, people often think of length. But in reality, the more important factor is mass because length can be misleading. A dinosaur like Argentinosaurus may be much longer than a blue whale, but most of that length is just a thin neck and tail, making its total mass only about 80 to 90 tons, still far behind the blue whale. There are even longer species such as marine ribbon worms that can reach more than 50 m, but are as light as a piece of wet string, which does not really make them giants. Blue whales are at the top because it is a dense, heavy body mass. So what about Ichthyotitan?

[00:03:11]Initial estimates show that it is about 26 m long and weighs about 120 tons, which sounds smaller than a blue whale.

[00:03:21]But the problem is that these numbers are not as simple as we think. Fossil evidence and data limits.

[00:03:27]Our entire understanding of Ichthyotitan is based on only two jawbones found.

[00:03:32]While blue whales have been studied on thousands of individuals, this creates a huge difference in accuracy and more importantly, the probability that those two bones belong to the largest individual that ever existed is almost zero. Which means that the true size of this species may be much larger than what we are seeing. And when looking at the average number, blue whales actually only weigh about 100 to 150 tons and do not always reach 200 tons, which makes the distance between the two species much more blurred and opens up the possibility that they may actually be equal. Aust Colossus and the possibility of exceeding limits.

[00:04:14]The story becomes even more interesting when scientists re-examine an old fossil called Aust Colossus. A giant bone fragment found before, but never clearly classified because of its absurd size.

[00:04:27]Now when compared to Ichthyotitan, they realized that this may be the same type of creature or at least the same group.

[00:04:35]And it is worth noting that this specimen is even larger. When put into calculation, the estimated size can reach nearly 29 m and weigh about 175 tons. And if we consider this to be just the size of a large adult individual, then the maximum size of this species can reach about 280 tons, far exceeding the 209 tons of the largest blue whale ever recorded. Although this is just speculation, it is not unreasonable.

[00:05:07]Why can a reptile be so large?

[00:05:10]What makes Ichthyotitan so strange is that it is a reptile while mammals are the group that often reach large sizes.

[00:05:18]Whales need a thick layer of fat to keep warm and a heavy skeleton to sink into the water. While reptiles are usually lighter and more flexible. But Ichthyotitan takes a different path.

[00:05:31]Despite having a dolphin-like shape, but in reality that is just the result of convergent evolution when different creatures find the same optimal design to swim quickly in the water. Which shows that shape does not always reflect nature. And in this case a reptile has reached a size previously only seen in mammals. Advantages of huge size.

[00:05:53]To understand why it can be so large, we need to look at its habitat, the deep ocean, where buoyancy helps reduce the pressure of gravity, allowing creatures to grow far beyond the limits on land.

[00:06:05]Large size also helps reduce relative drag when traveling long distances, just like a large ship is more efficient than a small boat. In addition, large size also helps retain heat better, turning the body into a natural thermal battery, allowing it to live in cold environments. And most importantly, the abundant food source at the end of the Triassic period, the ocean was filled with large creatures enough to feed a giant predator without much competition.

[00:06:34]The collapse of the ecosystem.

[00:06:36]But that advantage did not last forever.

[00:06:39]About 201 million years ago, a mass extinction event occurred when Earth experienced massive volcanic eruptions, releasing large amounts of CO2 into the atmosphere, causing climate change and ocean acidification.

[00:06:55]This did not kill Ichthyotitan immediately, but destroyed its food source. And for a creature that needs to consume huge amounts of energy every day, losing its main food source is a death sentence. The giant size that was once an advantage now becomes a fatal weakness. 200 million-year gap. After this event, Ichthyosaur species still existed, but they no longer tried to reach giant sizes. For the next 200 million years, no creature reached the scale of Ichthyotitan. It was not until mammals returned to the ocean and evolved into whales that giant size reappeared, but this time in a completely different direction, not hunting, but filter feeding. And this shows that reaching giant size depends not only on the body, but also on the survival strategy. Open questions and real limits.

[00:07:48]What is amazing is that this entire story is based on only three bones, while most of the creatures that have ever existed have never been fossilized.

[00:07:57]Which raises a big question whether 200 tons is really the limit or just the limit of what we have found. It is very likely that somewhere in the past there were even larger creatures that have completely disappeared without leaving a trace.

[00:08:13]And if we are only looking at a very small part of history, then what remains is still buried under millions of years of time. Ichthyotitan is not just a giant creature, but also a rare experiment of evolution. A moment when nature pushed its limits far beyond what we ever thought possible and then disappeared.

[00:08:33]Today blue whales dominate the ocean, but millions of years ago that position belonged to an ancient reptile that we only know through a few bones. If you want to explore more stories like this, please subscribe to the channel and press like to not miss the next content.