when I visited new zealand Iwas told there was no indiginious mamels those present were all introduced. Why?

Answer 1

Whoever told you that was incorrect.
There was one type of native land mammal – the bat. There are three types of native bat species - the long tailed bat, the lesser short tailed bat and the greater short tailed bat (this one is apparently extinct according to the Department of Conservation).

There were also marine mammals such as dolphins (Hectors & Maui’s spring to mind)

As to why the other mammals were introduced – all sorts of reasons! Farming is one. NZ’s pests tended to have actually been introduced in order to get rid of another pest or for their fur.

By the way, NZ may only have the bat and the dolphins but there is a fantastic array of native birds here :)

Deer, goats, rabbits, possums and many others are pests. And they certainly were not native :)

Answer 2

The islands of New Zealand separated from the rest of the world before mammals evolved. Australia also separated before mammals evolved, but late enough to get marsupials. (NZ and Australia are great demonstrations of the silliness of the Noah's flood myth.)

The Maori people have only been in NZ for about 1000 years.
Someone said deer were native. Wrong.

Answer 3

New Zealand is a remote island group and was colonised by animals arriving from elsewhere. These were birds, reptiles, insects and spiders. The animals that arrived then evolved into the species we know today. No land mammals survived the journey so all the land mammals, dogs, cats, possums, wallabies, goats, sheep, deer, horses, rats, mice etc were introduced by humans either by accident or design.

Answer 4

the only native mammals here are various coastal mammals, such as the New Zealand hector dolphins, the New Zealand fur seal, the only land creatures are birds, there are no land dwelling mammals native to NZ, except for mountain goats and deer