One of New Zealand's most destructive introduced pests, this rat arrived with European settlers in the 18th century. It is larger than the ship rat and the kiore, with a heavier body and a shorter, thicker tail. The brown rat is an excellent swimmer and often lives near water, including sewers, streams, and wetlands. It is also a skilled climber, though not as agile as its smaller cousin. The brown rat's impact on native wildlife is severe. It preys on the eggs and chicks of ground-nesting birds. It eats lizards, insects, and weta. It competes with native species for food and destroys the seedlings of native plants. In urban areas, it spreads disease and damages buildings. In farmland, it eats crops and contaminates feed. The brown rat is a generalist, and it thrives wherever humans provide food and shelter. Unlike the ship rat, which prefers forests and scrub, the brown rat is most common around human habitation. It lives in barns, rubbish dumps, sewers, and under buildings. It is the rat of the city, the rat of the farmyard, the rat that scurries through the dark while the city sleeps. Its populations are controlled by poison and traps, but it always returns. The brown rat is a survivor. It has followed humans across the globe, and it will follow us wherever we go. The brown rat's breeding rate is astonishing. A female can produce up to six litters per year, with up to twelve pups per litter. The pups reach sexual maturity in just three months. In theory, a pair of brown rats could produce over a thousand descendants in a single year. In practice, most die young, eaten by cats, dogs, or birds of prey. But enough survive to keep the population stable. The brown rat is not going anywhere. It is part of the human ecosystem now, and we have learned to live with it, even as we try to kill it.