In prehistoric times, crocodiles had a close relative called the Brachychampsa which could only eat meat.
Yet some of those reptiles had an advanced organ called the Foramen of Panizza, which controls blood flow throughout the body.
That's a very big reproductive advantage!
This organ not only allows the crocodile to be able to stay submerged in water for extreme amounts of time, but also can direct blood to the stomach, allowing them to munch on more food than other animals.
It has been quite a mystery why crocodiles have managed to survive on the Earth dating back to even before the Triassic Period, yet it is all due to their adaptation to the world around them.
Most of reptile life died out after the impact due to starvation, including the Brachychampsa since there was no option for the carnivorous reptile.
The Foramen of Panizza is a valve that directs where blood should be channeled in the body.
When the reptiles that didn't have this organ starved to extinction, the few crocodiles that did thrived by passing this hereditary trait on to each new generation.
The Foramen of Pizzamen directs more blood to the stomach, allowing more enzymes to be produced. This allows crocodiles to absorb nutrients from anything such as bones or fur. This allows them to survive much easier in harsh environments.
Because the asteroid left a cloud of ash in the air and on the ground, most plant life died off, killing the majority of life on Earth.
The crocodiles with the organ very quickly became the majority phenotype, since it was the only one for large reptiles to have survived the horrid asteroid.
Natural selection allowed for crocodiles to become an apex predator in many ecosystems.
Now, crocodiles still thrive in the animal kingdom due to this adaptation. They can survive even the worst of climates, allowing them to pass on their adaptations to their strong offspring.