The apparent different sized echidna on some of the 5c has been known for a number of years with separate articles by John Cook and Lyndsay Bedogni in Australian Coin and Banknote Magazine in early 2004 and they are also mentioned in one of the popular coin catalogues. The "large echidna" could be identified by the small gap between the bottom of the echidna and the rim of coin; the "small echidna" by the large gap between the rim and the bottom of the echidna. To the naked eye the difference is quite obvious. When I was preparing images of the two echidnas (on 1986 dated coins) I decided to line them up to show the difference in size. As you can see from the picture below the size difference is illusory.
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Ian Harshorn has commented on the different positions of the echidna on the 1972 five cents. In that article he also says that
"The design(s) themselves are the same size, but can give the impression of being a small and large design, similar to the 1984 and 1986 coins."
Given what we have observed on the 1986 dated coins, it is instructive to compare the reverses of the 1966, 1977 and 1988 five cent. The echidna designs have been called "large echidna", "small echidna" and "new large echinda" respectively. As we can see from the picture below, all three appear to have the same size echidna and within the limits of our measurement, the 1966 and 1988 appear to be in the same postion. However detailed analysis does show a tiny difference between the two "low echidna" designs/
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On which years do we find which echidna?
| Year | Die Type | Comments |
| 1966-1971 | Low Echidna Only | - |
| 1972 | Both | Low echidna is much scarcer |
| 1973-1983 | High Echidna Only | - |
| 1984 | Both | New low echdina design. Appears to be reasonably scarce for 1984 dated coins. |
| 1985 | High Echidna only | Low echidna has been rumoured but never confirmed. |
| 1986 | Both | Both are reasonably common. |
| 1987 | Low Echidna | High echidna rare. |
| 1988+ | Low Echidna Only | - |
The "high echidna" is presumably due to another master die coming into operation in 1972. Was this due to the original master die being now unusable? In this case then the reappearance of the low echidna in 1984 must be due to a new master die with the echidna again in the "low" position. It is of course possible that there were other master dies used but the differences are too subtle for us to easily detect.