The following is an excerpt from "A Closer Look at the Evidence" by Richard and Tina Kleiss. The book itself contains MANY other such evidences of an Intelligence of some sort (Let's call Him God) that must have designed and built the Earth that we live in, along with its wondrous and mysterious different forms of life.
Evidence from Biology
"The rare Australian aquatic frog is a perfect example of one of nature's most amazing methods of reproduction. If other creatures attempted this same method, it would be fatal to their young.
After the eggs of the Australian aquatic frog are laid and fertilized, the female swallows them. Sometimes she waits until they have started to develop but once the young are in her stomach, the mother stops eating for the next eight weeks. After eight weeks, fully developed little frogs come out of the mother's mouth!
What other creature can swallow its young, discontinue eating for eight weeks, and incubate its offspring within its stomach? The young Australian frogs can do this because they release fine threads of special chemicals which prevent the mother's stomach from making digestive acids. These tiny frogs actually change the mother's stomach from an organ of digestion into a comfortable protective nursery. How did the baby frogs which were swallowed, learn to turn off their mother's digestive acids? How did they learn to pass this ability on to the next generation?"
Emphasis in original text.