Way back in the day (about 85 million years ago), New Zealand broke apart from Gondwana. I know this is unfathomably long ago, but if you imagine the Empire State building as a timeline, with the base being 85 million years ago, and the tip of the spike being the present, then my lifetime has extended for the top 0.1mm – less than the equivalent of a coat of paint on the tip of the lightning spike (not that you’d paint the lightning spike – that’d defeat the purpose).
The bit of ocean that appeared between New Zealand and Australia became the Tasman Sea, affectionately known nowadays as “the ditch”. Not many land dwellers managed to cross the ditch over the 85 million years following the separation. A few insects were probably blown across, and some small bats somehow later made the crossing to become the only native land mammals in New Zealand.
The separation from Gondwana occurred in a time when dinosaurs still ran the show, and mammals weren’t anything bigger than a mouse. It was only after the extinction of the dinosaurs that mammals really took power of the animal kingdom.
A fossil of a primitive mammal has been found in New Zealand from around the time of the separation, which is the only known example of a land mammal (besides bats), but it supposedly went extinct very soon after.
So New Zealand effectively became an ark, drifting away from the other continents carrying only a select few refugees – birds, reptiles and bugs.
This posed an interesting situation – there were so many niches to be filled on this ark, – forest, alpine, plains, coast – and only birds and reptiles to fill them.
Birds adapted over the next 85 million years to take on roles that we would normally associate with mammals – such as the huge Moa, a herbivorous grazer like a deer or a giraffe, which was so well adapted to life on the ground it had no wings at all.
Artist: Heinrich Harder.
Meanwhile, all over the rest of the world mammals were diversifying and coming to power. They had plenty of time to perfect the art of hunting, food gathering, surviving and reproducing (to make a huge generalisation). New Zealand’s animals just existed in blissful, defenceless isolation.
This includes our favourite national symbol – the kiwi. This obscure little round bird came to fill the role of bug and grub eater, which is a diet that never required its ancestors to leave the ground. There were no predators to escape from, so there was really no need for it to fly. The kiwi was very well adapted to its life on the ground….
…Then, out of the blue 700 years ago humans arrived, bringing mammals with them both as deliberate introductions and as accidental stowaways.
New Zealand would have been a mammal’s paradise for the newcomers – food didn’t run away, eggs were easy to steal, plants were delicious and easy to eat. It’s really no surprise that mammals have since wrecked havoc on our native species.
Their introduction to New Zealand could be likened to a knight turning up at a medieval battlefield with an AK-47 – it’s just not a fair fight.
So since humans arrived, about half of New Zealand’s native vertebrate species have been driven to extinction, and a whole lot more are pretty close.
There are some huge conservation efforts to save the survivors, and those which are just clinging on (I’ll take a look at some examples in another post). I think it is only fair to ask for the best protection possible for those which remain.
All photos: Wikimedia Commons.