Oh Baby! Which Animal Families Lay Eggs and Live Birth?
There are benefits to both styles, not to mention quirks: One frog species gives birth through holes in its back.
“Are snakes the only family that evolved multiple birthing options—egg or live birth?” Louis Meluso asked Saturday's Weird Animal Question of the Week.
While snakes are pretty unique in the animal kingdom, on this one they have to share the spotlight.
Many animal groups have some species that lay eggs and others that birth live young, including fish, amphibians, and yes, even mammals, says Whit Gibbons, evolutionary biologist at the University of Georgia’s Savannah River Ecology Laboratory. (See "What Comes Before Snake Sex? A Kama Sutra of Courtship Moves.")
Both methods have their benefits, he says: Egg laying allows greater mobility for the mother who is "not encumbered by large eggs or embryos for a prolonged period," Gibbons says,
