Editor's Note: This article is not what it sounds like. It is not about sex. It is about reproductive changes. I’d better explain. For centuries human scientists thought all frogs were primitive creatures (ha ha!). They thought all frogs reproduced the same way: After the female pushes her eggs out of her body, the male fertilizes them. The eggs then hatch into tadpoles. Eventually the tadpoles change into frogs. Very simple. This is true of many frogs, but not all. It is not true of coquí frogs. Scientists now know that many frogs have adapted reproductive behavior in several ways. This is particularly true of frogs that live on land. We have made sure we survive on land as successfully as we survived in the water!
Some of you have lived in hidey holes all your lives. You don’t go out. So let me mention a few facts. It takes young frogs about a year to become mature. Only then can you, well, reproduce. The wet season is best. Coquis lay eggs every six weeks. Of course, this depends on several factors. It takes between two and three weeks for the eggs to hatch.
Three Eleutherodactylus frogs from Puerto Rico have shown scientists just how complex we are. We would like to honor them now.
Caridad grew up near the west coast city of Mayagüez in 1870. She was an E. coquí frog. In 1871 a scientist found Caridad. He studied her carefully for awhile. While he was watching her, he discovered something amazing. Her eggs did not hatch into tadpoles. They hatched into miniature frogs! The scientist watched Caridad’s relatives and wrote up his results. The rest is history.
Scientists now call this "direct development." The eggs hatch directly into frogs. They don’t go through the tadpole stage. This happens with all Eleutherodactylus frogs. It also occurs in many other frogs. Without tadpoles, these frogs eliminate their ties with the water environment. We have Caridad to thank for sharing this detail with scientists.
Catarina was very shy. Yet she became the focus of some very private research. It found out how she and her husband Candido made babies. This happened more than a century after the birth of Caridad. Catarina was also an E. coquí. She became the first frog to show scientists that she and Candido made babies internally.
Before then, scientists thought all female frogs laid eggs. The male would then pass by and fertilize them. But Catalina and Candido didn’t do that. Candido fertilized the eggs when they were inside Catalina’s body. She then laid the eggs, and he guarded them. (Nice touch, Candido! He is no male chauvinist!)
Crysta was an E. jasperi frog. This is a recently discovered and very rare frog. Your humble servant has never met one. Crysta astounded scientists when she gave birth to baby frogs! She did not lay eggs, as most frogs do. She did not give birth to tadpoles. She "bore her young alive," to use an old-fashioned term. After she performed this sophisticated and widely heralded feat, Crysta returned to her home. There she lived out the rest of her life in pleasant obscurity.