“Flawless” for 200 million years?:
Surviving crocodiles did not change throughout millions of years because they arrived at an equilibrium where they were efficient and versatile enough that they did not need to evolve to exist, reports the Conversation. Punctuated equilibrium is seen in species that evolve based on external factors like climate change or mass extinctions rather than evolving through sexual selection or predator versus prey situations. The crocodile may have reached this equilibrium through their abilities to survive without eating for long periods, and their sensitivity to temperature changes.
Elizabeth Gamillo, “Are Crocodiles Flawless? The Reptiles Haven’t Changed in 200 Million Years” at Smithsonian Magazine
The study is open access.
Here’s that “Conversation” story:
Relatives of crocodiles have been around for an extraordinary length of time, their fossil remains having been found in rocks from the early Jurassic period, around 200 million years old. Stranger still, these crocodiles from the age of the dinosaurs often look surprisingly like the crocodilians of today. All modern forms have long snouts, powerful tails, armoured skins and a sprawling gait, and many fossil forms are extremely similar.
This lack of change over such a long time is highly unusual, especially considering the immense diversity of modern animals that has accumulated in a much shorter time interval.
Max Stockdale, “Crocodiles today look the same as they did 200 million years ago – our study explains why” at The Conversation
But if you are already a crocodile, where is there to go anyway? Pacifism? Veganism?
See also: Stasis: Life goes on but evolution does not happen