Marine Animals Do Not Grow Too Big While Living in Water (Study)

Grey whale getting out to breathe

The growth of marine animals is inhibited in water

Whales are among the biggest animals on Earth, but is it possible for them to get even bigger? Since people used to think marine animals got bigger than land animals, a team of researchers from Stanford started studying seals and whales. They sought to see if the creatures can grow even more, and discovered something interesting. Aquatic animals actually grow much slower than land animals.

Do whales grow in water?

Although one might expect a colossal whale to get even bigger, the sad truth is it won’t happen. When it comes to growth, it seems that land animals are much more likely to do it. This happens because growth suffers some constraints in an aquatic environment. Therefore, it’s impossible for whales to outgrow their current size.

Researchers developed a study that they published in the journal Proceedings of the National Academy of Sciences. The logical explanation to why whales stop growing is the following: marine animals should preserve their initial size to save some body heat and find food easier. It opposes some past theories which claimed the pressure caused by saltwater allowed creatures to grow more.

“Many people have viewed going into the water as more freeing for mammals, but what we’re seeing is that it’s actually more constraining,” said the author of the study, Jonathan Payne.

Marine animals can be big, but not too big

The study made light on another theory, which claimed all marine animals are related, since their body shape is so similar. However, a study on living creatures and fossils revealed many of these marine animals are actually descended from land animals.

It turns out land animals could evolve and grow quickly once they reached an aquatic environment. Growing up to a certain size was essential for their evolution, as the bigger they were, the better. However, this is true only to a certain limit.

In other words, whales and other marine animals need to grow big to preserve their body heat. Smaller creatures lose body heat more quickly, and this is vital while living in water. Also, they stop from growing because of metabolism issues. The bigger they get, the slower their metabolism, so it wouldn’t be evolutionary practical to be too big.

Image source: Wikimedia Commons

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Allan Austin


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