A new research finds that the average size of marine creatures has increased by a factor of 150 over the past 542 million years. The largest sea creature on record is blue whale, which sizes approximately 30 meters.

The study findings support Cope’s rule, which states that the evolution of animal lineages towards larger sizes over time. The study is published in the journal Science.


The study was conducted by paleobiologist, Dr. Noel Heim of the Stanford University, and his colleagues. The scientists claimed that their study dataset involved nearly 75% of all marine genera and about 60% of all the animal genera that ever lived, making it one of the most comprehensive tests of Cope’s rule.

Dr. Michael Berenbrink of the the University of Liverpool also admired the researchers for compiling an “incredible” data set.

Dr. Heim told BBC News that they had at least 50 high school students working on it through last five years. The size and time of existence of animals were then fed into a computer program to run simulations to study how they might have evolved given a chance.

The study also found that bigger sea animals always survive and enjoy bigger chance of surviving. The researchers observed a pattern of increasing body size.

Dr. Heim explained that the degree of increase in body size, both mean and maximum sizes, could be attributed to some active evolutionary process promoting larger sizes. The bigger sea creatures can move faster and protect themselves against their predators.

Dr. Heim further explains why bigger could be better for sea creatures. He points that bigger size makes it easier to eat other animals and also to be more active given the higher mass relative to their surface area. Larger body size also contributes to a higher metabolic rate, contributing to a more active lifestyle.

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