They are really unusual mammals as they lay eggs!
In the Perth region the only monotreme repesentative is the Short-beaked Echnida (Tachyglossus aculeatus). They are probably more common in the bush than seen.
The best place to see them is Dryanda Woodland – about 2 hours out of Perth – a stronghold for many other marsupials. Another location is Boyagin Nature Reserve. They can often be seen during the day and also at night.
I have also seen them by chance in the Perth Hills and near the Julimar State Forest.
Echidna are found throughout most of Australia. In PNG there are 3 other long-beaked species in the genus Zaglossus.
They can sometimes be shy – curling up, just showing there spines. Often sitting down a short distance away for a few minutes will give it the chance to settle down and amble on its way.
Evidence of Echidna feeding can be found but messy diggings like these below.
The only other monotreme species is the Platypus Ornithorhynchus anatinus found on the east coast of Australia – not on the west coast.