(S)cientists discovered that glass-frog eggs hatched about 21 percent earlier on average when the fathers were removed. They hatched up to about 34 percent earlier when conditions were drier, suggesting that dehydration was the cue the eggs relied on to hatch early.

"Embryos can cope with delinquent dads," Delia said.

The researchers suggest this kind of embryo behavior may be common among species that provide care to eggs, such as insects, bony fishes and amphibians. "Variation in parental care seems to be the norm rather than the exception," Delia said.