These remarkable creatures are known as NEW GUINEA GIANT SPINY STICK INSECTS and come, as the name would suggest, from Papua New Guinea which is the large island to the north of Australia. 

They can reach large sizes and as adults they are usually a beautiful and very dark brown or 'mahogany' colour, almost looking as if they have been polished like a piece of wooden furniture!  This is an adult female looking particularly gorgeous:

The males are almost as large as the females and they have a very sharp spine on the 'thigh' part of each of their back legs, which they can and will use to defend themselves if they are disturbed or feel threatened.  The males are also able to produce a very unpleasant smell if they feel threatened, and this often causes potential predators to back away and decide against attacking them!

Despite their large size as adults, like most stick insects these start out in life as very small babies.  I have been fortunate to have had lots of eggs from this species in the past and have hatched several hundred babies during my time keeping them.  Pictured below are two babies or nymphs next to a 10p coin, so you can see how small they are to start with!  What is even more amazing is that the babies each come out of a tiny egg, and there is one such egg at at the top left of the picture.  How such large babies can come out of such tiny eggs I don't think I will ever understand!

Even though the nymphs start out brown in colour, it is not long before they turn a lovely shade of mossy green, like those in the pictures below:

As they continue to grow their colour gradually starts to change back to brown again, so in this way they end up going full circle from brown to green and back to brown again, before turning the beautiful mahogany colour when they eventually become adults!

It is easy to tell the male and female nymphs apart in this picture above, as the female on the left has a very distinctive egg-laying tube (or ovipositor) at the end of her body and the male on the right has the single sharp spine on each of his back legs as described above!