Credit: Picture: Jane Fenelon
Scientists from the University of Melbourne and University of Queensland have revealed the mystery behind the unique reproductive parts of the much-loved echidna.
In the paper, The Unique Penile Morphology of the Short-Beaked Echidna, Tachyglossus aculeatus , the team detail how the male monotreme s testes never descend, have no scrotum, and when not in use, their penis is stored internally.
They also detail how the echidna penis has four heads, which are actually rosette-like glans at the end. Just two of the four glans ever become functional during erection and which glans are functional appears to alternate between subsequent erections.