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!
Collecting faeces for lab tests
Colony cats were fed different diets for three weeks before their faeces was collected for analyses.
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.
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.
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.
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.
Testing food preferences of cats
Cats were fasted for two hours in the mornings and then presented with different foods (lamb and beef parts) to measure their consumption.
Sampling cats for feline immunodeficiency virus (FIV)
Buccal swabs (inside the cheek) were collected from almost 200 cats at 15 veterinary clinics.
Testing a cat food supplement for tooth health
Colony cats were anaesthetised, and all plaque was removed from their teeth. Four weeks later, new plaque build-up was measured.
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.
Testing pain meds for disbudding
The horn buds of young calves who were slightly sedated were burned off with a hot iron. Half of them received pain meds beforehand, and blood samples were taken before and after. After 24 hours, the second group received pain meds, too.
Comparing weight gain with different diets
Newborn calves were raised on various milk, pasture, and pellets combinations. They were slaughtered at two years old, and their “quality” was measured.
Checking endometritis rates in dairy herds
Some cows in several dairy herds were selected, and their vaginal discharge was measured and sampled. They were then impregnated as per standard agricultural practice.
Testing a supplement for more calcium intake
Pregnant cows were fed with or without a specific feed additive. After birth, all were fed the same diet. Blood samples were taken in the weeks around birth.
Testing a fertility treatment
Cows with fertility problems were treated with hormones for ten days or left untreated. All were then artificially inseminated.
Studying diarrhea infection
New mother cows had blood samples taken. If the sample was negative for a diarrhoea virus, they were sampled again after a while.
Studying Ikeda infection and treatment
Regular blood samples were taken from cows on three different farms. Only some were treated against the parasite. Milk production and fertility were recorded.
Testing a “Kiwiball” to teach kiwi aversion to dogs (2014)
Dogs were exposed to a device mimicking a kiwi bird, getting an electric shock upon touching it. The learning effect was tested several weeks later.
Testing a morphine alternative for pain
Dogs undergoing castration were treated with different pain relief and their pain response was measured. During surgery, EEG was measured to see differences in response to the process. After surgery, the pain level was determined through a behavioural assessment several times.
Studying selenium metabolism
Cats and dogs were fed diets with different selenium supplementation for three weeks in individual metabolic chambers. A liver biopsy was taken under anaesthesia.
Studying selenium metabolism
Animals were fed diets with different selenium supplementation for three weeks in individual metabolic chambers. A liver biopsy was taken under anaesthesia.
Evaluating the efficiency of kiwi aversion training
Dogs who had experienced either none, one or two times of kiwi aversion training with shock collars were observed near a caged live kiwi.
Testing treatment of a neurodegenerative disease
Dogs with Mucopolysaccharidosis (MPS IIIA) received medication, either from birth or 12 weeks to 23 weeks of age. One group received a placebo. Drugs were given under anaesthesia, either as injections into the vein or close to the brain. At 23 weeks old, all puppies were killed and their brains removed.
Testing a “Kiwiball” to teach kiwi aversion to dogs (2010)
Dogs were exposed to a device mimicking a kiwi bird, getting an electric shock upon touching it. The learning effect was tested several weeks later.
Testing new toxin against stoats and wild pets
Dogs, cats and stoats were fed different versions of toxic bait. Symptoms and time of death were monitored. Four dogs and two cats survived, but their fate is not stated.
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.
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.
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.
Studying gut bacteria in fish
Nine fish were caught by underwater spearing and killed so that samples could be collected from their digestion tracts.
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.
Using fish to study the impacts of Climate Change
Fish were either bought or caught and killed so that they could be dissected.
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.
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.
Testing a seizure medicine for preterm babies
Pregnant guinea pigs were induced to give birth early, to test medication on their pups.
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.
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.
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.
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.
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.
Studying trauma and treatment of cochlear implants
After destroying their hearing with noise, guinea pigs were fitted with cochlear implants. Treatment success was tested before they were killed.
Studying methane emission and meat quality
Lambs were tested and killed to assess the relationship between methane emissions, carcass weight and meat quality. Almost 2,000 were put through emission measurements. Over 17,000 were slaughtered.
Testing a UV treatment for bacterial eye infection
Pigs’ eyes were acquired for testing a new treatment, followed by tests on live mice, most of whom were killed.
Testing if anaesthesia affects the sleep–wake cycle when combined with light treatment
Mice were kept on a 12-hour light/dark cycle and then switched to total darkness. During this time, they were exposed to light once, either with or without anaesthesia. The effect on their activity cycles was monitored. In the end, all were killed.
Testing a new Alzheimer’s drug
Newborn mice were killed to collect brain tissue. Adult mice were used to test drug reactions. They were anaesthetised twice; to inject the drugs and to flush their hearts and take their brains.
Testing Alzheimer’s treatment on mice
Transgenic and “normal” mice were injected with a special protein and a chemical to mark new brain cells that may have been produced.
Studying Alzheimer’s and stroke symptoms
One group of transgenic mice were bred and killed at either four or 12 months of age by flushing their hearts. Another group was anaesthetised and caused to have a stroke. They were killed the same way.
Killing rats and mice for tissue
Rats and mice were anaesthetised, and their necks were broken. Their tissue was then used for research.
Testing migraine drugs
Mice were injected with potential migraine drugs and anaesthetised. Ultrasound imaging of their ears was taken. One ear was rubbed with capsaicin to record the increased blood flow and compare different drugs, doses, and time points.
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.
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.
Harvesting colon tissue for laboratory tests
Pigs were killed and their colon tissue was used for laboratory testing.
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.
Testing the strain on a temporary surgical implant
A surgical implant was screwed to a severed pig head, and measurements were taken via laser scanning.
Testing the effect of different species’ milk on protein digestion
Piglets were fed different kinds of milk from other species for 15 days. They were killed to dissect their stomachs.
Testing a UV treatment for bacterial eye infection
Pigs’ eyes were acquired for testing a new treatment, followed by tests on live mice, most of whom were killed.
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.
Studying how ageing affects brain chemistry
Rats were kept in germ-free, individual cages before being killed. Their brains were used for tests.
Studying cell death in breast tissue
Mother rats had some of their newborns taken away, and several of her teats were sealed off after two weeks. They were killed after different waiting times to analyse the dying tissue.
Testing blood pressure drugs against seizures
Rats were implanted with devices to measure heart and brain activity through induced seizures without being anaesthetised. They were killed two days later, and their hearts were taken.
Testing new drug formulations
Rats and rabbits were injected with a new anaesthetic, pinching their paw repeatedly to measure reflexes. Rats were giving the medication until they died.
Testing effects of meth on brain protein
Rats were taught to inject themselves with meth or a saline solution when they pressed a lever. After 20 days, there were two weeks of abstinence. In the end, all were killed to dissect their brains.
Testing medications for drug addiction
Rats were taught to inject themselves with cocaine when they pressed a lever. Through many cycles of establishment and withdrawal, medications were tested for their effect on drug-seeking behaviour. Other rats were tested for their activity level on cocaine with or without medication. Some were put into water-filled cylinders to examine if medication influences how long they swim.
Teaching animal researchers
A range of animals is used to teach researchers handling and experimental methods.
Testing a new pain medication
Rats were operated on to cause pain build-up in their hind leg. After 10 days, they were injected with different variations of a drug or just a control solution. The effect was tested by poking their hurting leg and having them balance.
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.
Developing “hyperimmune” milk
Sheep were injected with Covid-19 vaccines to see if they produced milk that could be marketed to consumers as providing immunity against certain diseases.
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.
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.
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.
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.
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.
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.
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.
Harvesting eyes for lab tests
The eyes of pigs and rabbits killed for experiments were used to analyse the structure of the cornea.
Testing a new vaccine
NZ White rabbits were injected with a new vaccine type several times before being killed.
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.
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.
Using a new imaging technology
One NZ White rabbit and rats were killed, and their eyes were removed to use for the study.
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).
Mapping wave patterns of the small intestine
NZ White rabbits were anaesthetised, their intestines were used for electrode mapping, and then they were killed.