What do the horseshoe crab, chambered nautilus, goblin shark, tuatara lizard, velvet worm, lungfish, tadpole shrimp, and the indestructible beasts called tardigrades (which look like bears but are the size of the period at the end of a sentence) have in common? These and a very few other animals are extreme survivors. All of them have been around at least 125 million years, surviving mass extinctions like the one that ended the dinosaurs. Evolution may have altered their physiology through the eons, but not their appearance. More than 99 percent of all life forms have gone extinct during the 3.6—billion—year history of life on Earth. How have these "living fossils"-these living links with Earth's prehistoric past-survived? The search for answers is leading scientists to amazing discoveries-not only about the past, but also the future-and providing vital clues to how life on Earth evolved. The survival secrets of these ancient creatures could lead to new medicines and treatments for disease. | Extreme Survivors by Kimberly Ridley, Picture Books | Indigo Chapters