Rats (and mice) are often the animals of choice to try and model human conditions, treatment and body functions - even though we know that using animals to try and model people fails over 90% of the time.

Mice and rats are commonly used due to their small size, low maintenance (i.e., they are easy to house and care for), short life cycle, and ability to breed quickly (allowing large numbers to be generated for studies).

They also share many of our genes.1 However, that's not surprising. Even cats share many of our genes.2

Rats are used is some of the most gruesome experiments that involve things like force-feeding, poisoning, oxygen deprivation and invasive surgery.

Rats in NZ have been used for:
  • Drug research, including safety and efficiency testing.
  • Teaching purposes in schools, mainly dissections.
  • Investigating ways of killing wild rats. (i.e., research into effective poisons and traps).
  • Medical research, including research into the development of severe diseases (i.e., stroke, diabetes, cancer), modelling neurological disorders (i.e., Schizophrenia, Autism), modelling mood disorders (i.e., example, anxiety, and depression) and research into tinnitus.
  • Drug addiction research including research into the development and suppression of addictions and the impacts of drug use.
  • Basic biological research, including research into digestion, aging, nerve damage, obesity and how the brain functions.

Places that use rats for science in NZ include crown research institutes, private companies and universities. In fact, most universities have their own breeding colonies. Otago University states on its website that they have a dedicated rat testing room in the Behavioural Phenotyping Unit.3

Rats used for science in NZ are sourced from breeding units, public or commercial sources, the wild (captured) and they are imported from overseas.

Discover real-life examples of how rats have been used in NZ below!

Measuring thickness of blood vessel walls

Colony cats were anaesthetised, and the blood vessels under their tongue were measured with a special hand-held camera.

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Collecting faeces for lab tests

Colony cats were fed different diets for three weeks before their faeces was collected for analyses.

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Surveying caregivers on their cat feeding

New Zealand cat caregivers filled in an online survey about their household demographics and what/how they feed their cats.

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Testing new toxin in Hawke’s Bay (again)

Toxic bait traps were placed on a property in Hawke’s Bay. Cat population changes were monitored with stationary cameras.

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Assessing stress reaction to anaesthesia in cats

Cats were put through several anaesthetic infusions with six-day breaks in between. Regular saliva samples were taken 24 hours before and after, and urine was collected through a wire mesh tray.

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Trialling ready-made toxic bait

Toxic bait stations are set up in a regular pattern in an area and left for two weeks. Trial cameras and tracking tunnels monitor the effect on the population.

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Studying medical data of cat and dog CT-imaging

Medical data from cats and dogs were gathered, and animals that had been euthanised for other reasons were examined.

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Testing if a human diabetes drug might also work in cats

Research cats were placed in individual cages four times (one week each time) and injected with either a diabetes drug or a control solution. Several blood and urine samples were taken.

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Studying the genes for hairyness

The hairiness of male and female cattle was rated. Some animals had their rectal temperature taken repeatedly, and some were shut in a hot room for two hours to make them sweat. Eight calves were killed to take brain samples.

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Optimising fertility treatment

Young female cattle were treated with different hormonal injections to control their fertility cycle. Around ten rectal ultrasounds were done on each of them within 11 days, and several blood samples were taken in the next month. All but nine were artificially inseminated. The nine animals showed no fertility signs and were therefore useless for the study and the industry.

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Trying out a health test for breeding bulls

Breeding bulls were infected with a skin fungus that usually results in a dangerous build-up in the gall and eczema. Through a special diet, bulls can be tested for their reactions via repeated blood samples and ranked for their genetic quality.

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Testing a vaccine against miscarriage

Younger and older pregnant cattle were injected with a new vaccine against a parasite or just control solution. Skin reactions to the injection were checked, and blood samples were taken. Farmers reported miscarriages when they happened, and dead foetuses were collected if possible. If female calves were born, blood samples were taken from them, too.

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Studying Johne’s disease

Some female calves of a group were infected with bacteria causing life-threatening sickness. Poo samples were collected directly from the rectum of all calves every other month. Half were killed to be dissected at 7 months, the rest at 15 months.

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Studying Johne’s disease bacteria

Blood samples were taken from sick dairy cows who were sent to slaughter to see if their immune system was even putting up a fight. After slaughter, organ samples were taken.

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Finding a gene to increase casein in milk

Breeding bulls were evaluated on their quality by judging, breeding, and milking their daughters. No exact numbers are stated how many lived to the end of the study (5 lactations).

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Testing a new way to treat liver flukes

Young cattle were infected with liver flukes. They were treated with different medications or left untreated. Regular blood samples were taken from all animals for three weeks, and they were killed ten weeks later.

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Analysing Greyhound race injury statistics

Historical data on Greyhound races between 2014 and 2019 were analysed. Injuries and deaths were investigated.

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Using bones of euthanised shelter dogs

Cadavers of dogs killed at an animal shelter were donated. Holes were drilled into leg bones and fitted with screws.

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Investigating farm dogs for four years

Working farms dogs were examined regularly for four years. Health problems and fate were recorded.

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Transplanting faeces as diarrhoea treatment

A dog with diarrhoea was treated with laxatives and warm water before a faeces sample from a healthy dog was inserted into his colon. Samples were taken before and after.

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Testing the eyes of working dogs

Eye examinations were performed on working sheep dogs. Medication for pupil dilation was given, and faeces samples were taken from most dogs.

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Analysing dog movements

Colony dogs were prepared with reflective markers and an activity collar. Their movements on a treadmill at various speeds were recorded.

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Testing the effect of diet on farm dog performance

Working dogs were fed a diet very high or very low in carbohydrates. Their blood glucose and activity were monitored three times over four days each.

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Testing a parasite treatment

After a pilot study with just one dog, six more were given an experimental parasitic treatment. Regular blood samples were taken through a catheter.

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Studying how viruses spread in fish

Fish were caught with nets and killed.

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Using fish to study the impacts of Climate Change

Fish were either bought or caught and killed so that they could be dissected.

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Overfeeding Zebrafish to learn about obesity

Normal and transgenic zebrafish were fed normally or way too much. The fish were taken out of the water for glucose tests and blood samples.

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Studying gut bacteria in fish

Nine fish were caught by underwater spearing and killed so that samples could be collected from their digestion tracts.

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Studying the sleep of sharks

Sharks were caught and kept in outside tanks. For the experiments, they weren't fed for at least 4 days, of which they spent 3 days in a measuring chamber not much bigger than the shark. Oxygen consumption and behaviour were continuously recorded for the last 24 hours.

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Infecting fish larvae as a potential model for humans

Zebrafish larvae were injected with bacteria to test how their immune system responds. This was repeated to test how well the immune system reacted and how long the effect lasts.

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Finding a “growth gene” in snappers

Snappers were caught from the wild and bred. Around eighty-thousand of their offspring were hatched and raised. At regular “grading” events, injured and deformed fish were disposed of. At just under a year old, around twenty-two-thousand were left and transported to a sea pen, where they were raised to 17.5 months old before harvesting.

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Testing how much fat you can feed fish

Fish in aquaculture were divided into groups and fed diets with different fat content. Fish were anaesthetised and faeces samples squeezed out of them.

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Developing a model for thermal stress in humans

Guinea pig pups were lightly anaesthetised, connected to devices measuring heart activity and breathing, and wrapped in a temperature-controlling blanket. Their body temperature was either forcefully raised or dropped.

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Testing how too much fructose is bad during pregnancy

Female guinea pigs were mated; some were fed additional sugary water until birth. The pups were used for several glucose tolerance tests and X-rays. All pups were killed in the end.

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Testing a seizure medicine for preterm babies

Pregnant guinea pigs were induced to give birth early, to test medication on their pups.

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Testing the effects of sedatives

Young guinea pigs were treated with different sedatives. Their heart rate and blood pressure were measured before and during each treatment.

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Testing a refined way of anaesthesia in guinea pigs

Guinea pigs were made to inhale anaesthetic gases. Different probes were inserted and attached to the animals to measure responses.

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Studying the effect of fructose during pregnancy

Guinea pigs were fed either normally or supplemented with fruit sugar before and during pregnancy until birth. Mothers and pups were tested for glucose tolerance.

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Studying the effects of meth

Guinea pigs were injected with sedatives, caffeine, and later meth. Under anaesthesia, their livers were cut out before they were killed.

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Studying preterm birth effects on the brain

Pregnant guinea pigs were grouped to give birth normally or be induced early. The pups were put through behavioural tests and then killed for dissection.

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Researching scoliosis genes

Transgenic mice with a specific gene defect were mated. Pregnant mice were at several time points. The unborn babies were taken, skinned, and gutted to stain their skeletons for better pictures.

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Studying hormone influences on obesity and fertility

Transgenic mice were bred to have diabetes symptoms. Together with control mice, they were fed a normal or a high caloric diet and compared for their fertility over 150 days.

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Testing a new stroke treatment

Mice were squeezed into plastic cones, and test drugs were dripped on their nose. An artificial stroke was caused by injecting a chemical into their brain. Before and after, mice had to perform behavioural tests. All were then killed to take their brains.

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Testing another new stroke treatment

Mice were operated on several times. They were made to experience an artificial stroke, were later injected with a possible treatment, and then were injected with a marker. The mice had their memory tested before they were killed.

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Testing prostate cancer drugs

Mice were anaesthetised, and their prostate was injected with cancer cells or a control solution. A 42-day treatment course started three weeks later with different treatment drugs and control solutions. In the end, all mice were killed.

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Testing a heart attack treatment

Mice were trained to eat jelly and then subjected to an artificial heart attack. They received either a new drug or a control substance. Regular heart ultrasounds were performed before they were killed and dissected.

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Studying ovary problems caused by testosterone

Transgenic mice were implanted with a capsule containing either hormones or not. Vaginal smears were done for several weeks, and serial blood tests were performed twice. In the end, all mice were killed.

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Testing an Autism treatment on transgenic mice

Mice were genetically modified to show "autism-like" symptoms. Together with control animals, they were either fed normally or with a high-zinc diet. Invasive behavioural tests were performed. At least some, likely all, were killed.

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Harvesting colon tissue for laboratory tests

Pigs were killed and their colon tissue was used for laboratory testing.

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Testing if pigs can be fed by-products from biofuel and food processing

Pigs were fed a standard diet or a diet containing by-products from other industries. They were slaughtered to compare meat growth and quality.

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Studying starch digestion in pigs to try and model humans

Pigs were fed different diets containing durum wheat or rice. Some had regular blood samples taken through a catheter. All the animals were killed at the end.

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Validating a treatment for stomach muscle dysfunctions

Pigs were anaesthetised, their bellies were opened, and electrodes were placed on their stomach walls before and after damaging some stomach tissue with heat. All pigs were killed.

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Assessing pigs as digestion models for humans

Titanium tubes were implanted into pigs’ intestines. Digested food was collected through the tube for 9 hours.

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Testing the effect of different species’ milk on brain gene expression

Piglets were fed different kinds of milk from other species for 15 days. They were killed to dissect their brains.

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Testing transmitter implantation on wild pigs

Wild pigs were captured, and three different tracking devices were fixed to or implanted into each one. After 104 days, they were tracked down and killed.

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Investigating oxygen content in the gut

Pigs were fed diets with different or no protein sources as a control. After a week, all were killed.

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Studying food intake in an autism "model"

Pregnant rats were injected to cause autism-like symptoms in their babies. The male babies were put through behavioural tests with control animals as well as a feeding study. Some were fasted for 16 hours and killed by flushing their hearts.

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Testing the safety of a probiotic supplement

Rats were force-fed with a probiotic solution or control solution. After two weeks, they were killed for dissection.

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Studying the effects of obesity and mussel powder on bone health

Rats were kept alone and fed different diets containing normal or high amounts of fat or sugar. Some were supplemented with Greenshell mussel powder. X-rays were done, and some rats' ovaries were removed. Ultimately, all were killed by bleeding them out.

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Testing if a brain region controls memory

Some rats had their brains surgically heat-damaged. Electrodes were implanted to monitor brain activity and to stimulate the damaged parts with light. Rats then had to re-perform memory tests to see the impact before all were killed.

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Studying the communication between inner ear and brain

Rats were anaesthetised, and their inner ear was partly removed, before parts of their brains were stimulated with wire electrodes. Reactions of the rat's eyes and brain were recorded. In the end, all rats were killed.

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Testing a connection between tinnitus and brain function

Rats were anaesthetised and one ear was damaged with noise. Rats were taught that silence meant they would get electric shocks and freeze in fear. This was a test for tinnitus.

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Testing diabetic rats’ hearts

Genetically diabetic fat rats and their lean littermates were anaesthetised. Ultrasound images were made from their hearts. All were killed and dissected.

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Testing the effect of diabetes on pregnancy hormones

Rats were anaesthetised, and their brain was accessed through the mouth to measure reactions to stimulation. In the end, all rats were killed.

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Investigating how worms spread between lambs and calves

Lambs and calves were infected with worm eggs to see if parasites from cattle can infect sheep.

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Using sheep to try and model how well humans will heal after dental surgery

Sheep had healthy teeth pulled out and the sockets treated in different ways to compare how well the body will heal after a tooth is removed when left untreated vs using a bone graft.

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Preclinical testing of a gene therapy for Batten disease

Sheep with and without a specific gene mutation were checked and scanned regularly for nine months. Affected sheep received gene therapy at different ages. Treated sheep were killed.

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Testing if blocking a cell signal can prevent foetal brain injury

Pregnant sheep were anaesthetised, and the foetuses fitted with electrodes. The umbilical cord was blocked for most of them, and half were treated with a test drug. Mothers and unborn lambs were killed three weeks later.

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Testing the combination of drugs for congestive heart failure treatment

Sheep were anaesthetised and subjected to surgery. Electrodes were used to pace their hearts faster while testing the effect of different drugs.

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Testing the best way to deliver gene therapy drugs

Sheep were anaesthetised. Their heads were drilled into, and their brains injected with test drugs. They were killed after three weeks.

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Testing the potency of pneumonia vaccines for sheep

Lambs were vaccinated twice and regular blood samples were taken for 34 weeks, to test different pneumonia vaccines for sheep.

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Testing the effects and wash-out of painkillers

Lambs were treated with different painkillers or no painkillers at all before tail docking and castration. Their behaviour was monitored.

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Investigating intestine movements

Young pigs and NZ White rabbits were anaesthetised. A part of their intestine was pulled out far enough to record its movements and signalling.

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Harvesting rabbit and pig eyes for lab tests

The eyes of slaughtered rabbits and pigs killed for experiments were used to analyse the structure of the cornea.

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Causing sinusitis in rabbits as a model

NZ White rabbits were anaesthetised, and a sinus tract in their nose was blocked for four weeks to cause sinusitis. After another ten weeks with regular samples, they were killed.

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Testing a new vaccine

NZ White rabbits were injected with a new vaccine type several times before being killed.

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Harvesting eyes for lab tests

The eyes of pigs and rabbits killed for experiments were used to analyse the structure of the cornea.

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Testing the toxicity of some substances

Young NZ White rabbits were force-fed different doses of toxic substances. Blood samples were taken before and immediately after killing them at set time points (or to end their suffering).

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Using a new imaging technology

One NZ White rabbit and rats were killed, and their eyes were removed to use for the study.

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Measuring contractions in exposed rabbit uteruses

Pregnant rabbits were anaesthetised, and their uterus was exposed. Measurements were taken while contraction-inducing injections were given. Then they were all killed for dissection.

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