Why does new zealand have native reptiles like lizards and geckos but no native snakes?
In: Biology
New zealand became an island before snakes existed so there was no way for snakes to get there. Sea snakes exist and can be sometimes seen around new zealand but they’re not settling on land. I lizards existed before snakes and existed in what is modern day new zealand before it became an island.
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Luck of the draw, really. There’s a lot of ways animals can get to islands and island biogeography is fascinating, but if they never got there, they never got there.
When New Zealand became an island in the late cretaceous, it meant that the only terrestrial animals living there were the ones descended from the animals living at the time of the separation (or which could swim or fly from the mainland, e.g. the probably-flighted ancestors of the kiwi).
There just didn’t happen to be any snakes living in New Zealand at that time, since snakes had only just recently evolved. For the same reason, there are no mammals endemic to New Zealand except for bats (which could fly there) and marine mammals (which could swim); all others living there now were introduced by humans.
There are snake fossils known from NZ, so presumably they died out at some point
https://www.nzgeo.com/stories/snake-in-a-lake/
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