if you are a humpback whale mother.
That is the finding of an Edinburgh-led study into the mammals, which migrate to tropical breeding areas each year.
Researchers found that new mothers opted for the shallows around the Hawaiian islands to reduce the likelihood of being sexually harassed by amorous males.
Their data showed that females with a newborn calf were often pursued by one or more males in deeper waters, meaning the mother and her baby had to increase their swimming speed by almost 75%.
Dr Alison Craig, a marine mammal scientist from Edinburgh Napier University, said: "There are no long-term social bonds between male and female whales, and the males approach lots of females in the hope that they will get the chance to mate.
"Our study suggests that unwanted male attention causes females and calves to increase their swimming speed, so mothers need to supply their calves with more milk to compensate for the extra energy they've used."