{"id":478,"date":"2024-05-07T07:54:26","date_gmt":"2024-05-07T07:54:26","guid":{"rendered":"https:\/\/sites.massey.ac.nz\/phoenixlab\/?p=478"},"modified":"2024-05-07T07:54:26","modified_gmt":"2024-05-07T07:54:26","slug":"reasons-to-kill-rats-one-two-three","status":"publish","type":"post","link":"https:\/\/sites.massey.ac.nz\/phoenixlab\/2024\/05\/07\/reasons-to-kill-rats-one-two-three\/","title":{"rendered":"Reasons to kill rats; one, two, three"},"content":{"rendered":"\n

There were no rodents in Aotearoa\/New Zealand before humans arrived. The first people came with Rattus exulans<\/em> (kiore, pacific rat), then later, different people brought different rodents (Rattus rattus<\/em>; Rattus norvegicus<\/em>; Mus musculus\/domestics<\/em>). Now there are rats in every corner of the country. <\/p>\n\n\n\n

About two years ago I got some new rat-traps and set them up around my home \u2013 near the house and in the forest fragment where I live.  I own 2.3 hectares of land that was once used for sheep farming, but the steep river terrace and gully would never have been very productive. The trees and punga in the gully were allowed to grow and they are expanding and replacing the gorse. I caught 29 rats in the first month.  I use snap traps mounted on tree trunks and baited with peanut-butter. After two years I have caught 300 rats. All but one of these 300 were Rattus rattus<\/em> – the ship rat, the black rat, the roof rat, the long tailed rodent. The single Rattus norvegicus <\/em>was killed in a stoat trap on the ground.<\/p>\n\n\n\n

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The number of Rattus rattus<\/em> I have caught each month<\/figcaption><\/figure>\n\n\n\n

Reasons I kill rats, number one:<\/strong><\/p>\n\n\n\n

A dead rat can\u2019t eat a native insect. In New Zealand forests\u00a0Rattus rattus\u00a0<\/em>spends about 70% of its time off the ground and eats insects and plants<\/a>. The insects it can find crawling about in the trees at night are tree w\u0113t\u0101 and ground w\u0113t\u0101 and cave w\u0113t\u0101 and stick insects and cockroaches and beetles and moths and caterpillars and crane flies and cicada and lots more.\u00a0\u00a0Rattus rattus\u00a0<\/em>also eat seeds and fruit and flowers and eggs and little birds in nests.\u00a0\u00a0But mostly it eats our native forest ectotherms \u2013 unless it’s dead. If the insects survive tonight, they might be food for the grey warbler or the piwakawaka (fantail) or the p\u014dpokotea (whitehead) or tui tomorrow \u2013 but these vertebrates are native to New Zealand and hunt during the day. At night the nocturnal insects might be eaten by ruru (owl) or a spider or a gecko. I\u2019m not anti-predation \u2013 but I\u2019d rather it was an endemic species who benefited.<\/p>\n\n\n\n

Reasons I kill rats, number two:<\/strong><\/p>\n\n\n\n

A live rat is home to the rat flea (Xenopsylla cheopis<\/em>)\u00a0and the flea is home to a bacterium called\u00a0Rickettsia typhi<\/em>. This bacterium causes the disease murine typhus<\/a> when infecting humans. Symptoms are fever, nausea, headaches, and muscle pain. Although murine typhus can be fatal if not treated with antibiotics most recover fully.\u00a0\u00a0Killing a rat results in the death of the fleas and the bacteria.\u00a0\u00a0I don\u2019t know how many fleas on my rats are infected with\u00a0Rickettsia typhi\u00a0<\/em>but disease reduction could save health care costs.\u00a0<\/p>\n\n\n\n

Reasons I kill rats, number three:<\/strong><\/p>\n\n\n\n

Every rat exhales carbon dioxide. 300 rats (about 30kg in total) are no longer contributing to greenhouse gas emissions. The invertebrates that the rats would have eaten get to walk away \u2013 they also release carbon dioxide but they are ectotherms, so their metabolic rate is much lower<\/a>. The fruit and seeds the rats would have eaten might germinate and produce seedlings. By reducing the number of rats in my gully I\u2019m reducing my carbon footprint.<\/p>\n\n\n\n

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Over the two years I have learnt how to rapidly distinguishing\u00a0Rattus rattus<\/em>\u00a0from\u00a0Rattus norvegicus \u2013\u00a0<\/em>Even if a rat is half grown the tail-to-body ratio, fur colour on belly, shape of face and size of ears will provide the information to separate the two\u00a0Rattus\u00a0<\/em>species.<\/p>\n<\/div><\/div>\n\n\n\n

My two local\u00a0Rattus<\/em>\u00a0species<\/strong><\/p>\n\n\n\n

Although I have killed 300 rats there are still more out there. I know I am not eradicating them from my property as there will always be more moving in. Most Rattus rattus <\/em>don\u2019t move much further than 100m from their home, if there is plenty of food. But on all sides of my place there are rat populations producing more offspring than can be supported by local food \u2013 so from all around me hungry rats will be arriving. The entire rat population was removed from a small Palmerston North forest fragment in 1977 but it took only two months for rats to recolonised the forest (Innes & Skipworth 1983<\/a>). The graph of number of rats killed per month shows that my local population is responding to the seasons \u2013 there is an increase in numbers in early autumn, fewer in winter but never a complete absence. Only if I built a fence could I make a forest fragment free of carnivorous mammals.  So, killing rats will not increase the local tui, kereru and the tomtit population but I have three good reasons to bait my traps again tomorrow.<\/p>\n\n\n\n

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Tree mounted snap traps<\/a><\/figcaption><\/figure>\n\n\n\n

Let the insects live, prevent disease and reduce carbon dioxide: <\/p>\n\n\n\n

saving the planet one rat at a time.<\/p>\n","protected":false},"excerpt":{"rendered":"

There were no rodents in Aotearoa\/New Zealand before humans arrived. The first people came with Rattus exulans (kiore, pacific rat), then later, different people brought different rodents (Rattus rattus; Rattus norvegicus; Mus musculus\/domestics). Now there are rats in every corner of the country.  About two years ago I got some new rat-traps and set them up around my home … <\/p>\n

Continue reading “Reasons to kill rats; one, two, three”<\/span><\/a><\/p>\n","protected":false},"author":82,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-478","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/sites.massey.ac.nz\/phoenixlab\/wp-json\/wp\/v2\/posts\/478","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sites.massey.ac.nz\/phoenixlab\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sites.massey.ac.nz\/phoenixlab\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sites.massey.ac.nz\/phoenixlab\/wp-json\/wp\/v2\/users\/82"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.massey.ac.nz\/phoenixlab\/wp-json\/wp\/v2\/comments?post=478"}],"version-history":[{"count":8,"href":"https:\/\/sites.massey.ac.nz\/phoenixlab\/wp-json\/wp\/v2\/posts\/478\/revisions"}],"predecessor-version":[{"id":494,"href":"https:\/\/sites.massey.ac.nz\/phoenixlab\/wp-json\/wp\/v2\/posts\/478\/revisions\/494"}],"wp:attachment":[{"href":"https:\/\/sites.massey.ac.nz\/phoenixlab\/wp-json\/wp\/v2\/media?parent=478"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sites.massey.ac.nz\/phoenixlab\/wp-json\/wp\/v2\/categories?post=478"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sites.massey.ac.nz\/phoenixlab\/wp-json\/wp\/v2\/tags?post=478"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}