The penis of an echidna has four heads but only two become erect at any one time. Now, Australian researchers have uncovered why. Scientists discovered the mammal has unusual reproductive anatomy that causes male echidnas to ejaculate from only two of their four penile heads at one time. The research, published in the peer-reviewed journal Sexual Development, found that echidna penises have...
Australian researchers discover why only two of echidna’s four penis heads become erect at one time
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