What anatomical feature do you find in a dolphin embryo that you won’t find on a newborn dolphin

What anatomical feature do you find in a dolphin embryo that you won't find on a dolphin when it's born?
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We had quite a few correct answers to last week’s quiz, and our winner (chosen at random) is Brooke who correctly stated that humpback whales have two openings to their blowhole whereas bottlenose dolphins only have one. Now, for this week’s quiz: name a body part that you will see in the first few months of a developing dolphin embryo that you won’t find on a dolphin calf when it is born.  Think you know the answer? Surf on over to thedolphnipod.com and click on Dolphin Quiz – leave your answer in the comments section. Winners will randomly be chosen from the correct answers, and will be announced on next week’s show.