Ship rat or Norway rat? They are similar, but here are some tips to help you tell apart these two common introduced pests in New Zealand.
New Zealand has launched an all out war against introduced predators that began back in 2016 when the government announced the country would be predator-free by 2050. Those predators are all introduced species that are incredibly harmful to the native wildlife of the country and have driven many species to extinction. Some of the main predators include possums, stoats, and rats. As Sun Tzu said, ‘Know the enemy…’. Or as one of my childhood favourites, GI Joe, said, ‘knowing is half the battle.’ In other words, we need to first understand these predators in order to be able to eradicate them.
3 Species of Rats In New Zealand
There are 3 species of rats in New Zealand – ship rat (most common), Norway rat (largest), and kiore. Ship rats and Norway rats are both quite common and can be found throughout the country. Kiore was the first rat to arrive in New Zealand around 1280. They used to be widespread, but since the arrival of the other two species they can now only be found in a few parts of the South Island and some offshore islands.
Ship rats are good climbers and thus are a serious threat to birds that nest in trees. On the other hand, Norway rats are not as good of climbers, but are good swimmers and tend to live near water.
3 Tips To Tell Apart Ship Rat and Norway Rat
These general tips will help you tell if you are looking at a ship rat or a Norway rat. However, I do want to caution you that it can be hard to know for sure depending on the state of the animal you are looking at. Most of the time that I see a rat I am looking at one that was caught in a trap and is dead. Whenever I’ve seen live ones they are moving fast and it’s hard to get a good look at them.
Thus, the dead ones in traps may be hard to distinguish these features depending on how long they’ve been there. If they are fresh then you’ll likely be able to figure out what kind of rat it is. However, if it’s been in the trap for awhile then you may only see some skeletons or part of the corpse. Having said that, here are a few things to help you tell if you are looking at a ship rat or Norway rat.
Tail
Ship Rat – the tail is longer than the body. Norway Rat – the tail is shorter than the body and tends to be a bit thicker.
Ears
Ship Rat – Have large ears. Rounded and hairless. The ears are big enough to cover the eyes. Norway Rat – smaller ears than a ship rat. The ears won’ t meet across the top of the head.
Size
Ship Rats – tend to be a bit leaner and smaller. Norway Rat – have a thicker body and can be quite big.
Colour?
While both types of rats are usually certain colours you can’t rely on colour to tell you what type of rat it is because the colour can vary quite a bit and be misleading.
Ship Rat – generally black or dark brown. They are also called black rats. Norway Rat – generally gray/brown or black with a pale underside.
Ship Rat or Norway Rat? Well, which is it?
Remember that photo from above. Here is another photo of it. This is a ship rat. Look at the tail – I know it’s hard to tell from the photo, but it is longer than the body. Then look at the ears – they look quite big, more than big enough to cover the eyes.