Is animal research necessary? Scientists Opinion

I a molecular biologist who has conducted and published animal research. BUT I feel very torn about their usefulness and the ethics behind animal research. Most molecular biology labs utilize animal research.  It is hard to get exact figures, but there are undoubtedly millions of vertebrate animals (mainly mice) in labs worldwide right now. And without going into detail, their experiences are incredibly unpleasant. Is animal research necessary?

Is animal research necessary? Image shows a mouse in a lab amongst lab equipment.
Is animal research necessary?

The obvious justification is that it is necessary.

But is it? I have to be honest. I have limited hands-on experience and have only directly been involved in a few animal studies (mainly because I have avoided them in recent years). But I also have vast experience reading papers involving animal studies and speaking to many colleagues. My opinion now is that animal models often used do not represent the human versions of the disease.  Therefore, they may have no/limited benefit to the research. Some isolated incidents indicate that animal models can actually mislead the researchers. Giving false hope for a treatment which won’t work in humans. Or animal results may suggest a treatment is safe to test in humans when it is not.

It is often joked about how often cancer has been cured in mice. So is animal research unnecessary?

Animal work in University labs is tightly controlled.

There are strict regulations that need to be met before animals can be used in research, and rightly so. These include the 3Rs (Replacement, Reduction and Refinement). The 3Rs limit animal use to only when it is absolutely necessary. However, in many ways the 3Rs are for show. A researcher can easily justify their animal work is necessary. I have yet to hear of an animal study being rejected. I am sure it happens, but anecdotally it appears to be rare. The main limiting factor for animal research in our lab has been funding and time, not getting the studies approved. 

Animal research is also meant to be as cruelty free as possible. Unfortunately, most animal research is very unpleasant for the animals involved. There is often no practical way to make the experiment pain free. These experiments, by necessity, are conducted in a lab with animals bred in cages. Beyond that, many experiments themselves are inherently painful/unpleasant for the animals. To study a disease the animal must be given the disease. And then at the end of the experiment the animals are almost always sacrificed (killed). This allows the animal to be dissected. Giving the researchers more information.

Cancer research

I am going to give an example of a widely used model for cancer research: a xenograft model.

Is animal research necessary? Image shows what a xenograft model is. Tumor cells are implanted into a mouse, allowed to grow and then treated. Different treatments can be compared for their ability to treat the cancer.

This model involves taking human cancer cells grown in the lab and implanting them in a mouse. The tumor is grown before being treated. Then different treatments in the different mice can be compared. This is probably the most commonly used method in cancer research to compare treatments. Unfortunately, though, this method does not strongly correlate to what will happen in a human.

We have cured cancer in mice hundreds if not thousands of times. The disease we are curing is not even remotely the same as it is in humans. In this model, we would be curing a human disease implanted into a mouse that has a limited immune system (a normal mouse immune system would reject the tumor implant). We know this does not translate to humans. It does not help inform clinical decisions. The amount the treatment works in the mice doesn’t give a good indication of how much it will work in a person and the mice not having severe side effects does not give useful information on how humans will respond.

So perhaps these animal studies are not very good at predicting how good a treatment will be in humans. But does it show a treatment will be safe? Sometimes. However, there are examples of drugs that appeared safe due to extensive multi-species animal testing that ended up being toxic to humans. E.g. BIA 10-2474 which, following animal studies, was given to human volunteers and resulted in 5 severe adverse effects including one death. These cases are rare, but still raise the question of how useful these animal studies really are.

So why do researchers do animal work?

3D living model is better than cells grown in a lab in a flask

The argument is that these models can be useful to test human health in a 3D living system that in some ways is similar to humans. This is better than using cells grown in a lab in plastic. I do not completely disagree with this. However, I do have ethical concerns with the amount animals are used and the potential usefulness of a lot of the research. There are also better animal models than the one example I gave above. However, the better models are normally more expensive and may require specialist training, making it more likely labs will use cheaper methods.

Need animal work to publish in good journals

If you are not a scientist you will not be aware how difficult it is to get research published. As a scientist you want to get your research published in as good a journal as you can. The better the journal the more prestige associated with the research. However, better journals require high quality research and they often expect animal research, especially if the research is exploring a new treatment. Researchers do not have a huge amount of choice about doing animal research.

Some animal work really does advance science

I have been quite negative about animal research up to this point. However, I have to acknowledge that some animal work does advance science. Obviously, a lot of experiments cannot be carried out in humans because they would be seen as unethical. With animals there is less restrictions. Additionally, animals have a quicker life-cycle and so can be used to study generational effects quickly (in some other articles on brainstorm mice studies are mentioned showing the effects of plastic or alcohol on fertility). The results in animals do often help inform what should be attempted in human studies (which are much harder to plan and get funding for).

I am simply questioning how useful a proportion of animal studies are. And does the end justify the means in this case? Could we come up with better ways to test new treatments without harming millions of animals every year?


I think there needs to be a shift in thinking from scientists, journals and funding bodies. Animals are not being used as sparingly as they could be. Could we limit the use much further? Only use models that have evidence of being translatable and only for new treatments/experiments which already have a large amount of evidence for their use in non-animal models. However, this is just one scientists opinion.

What do you think? Do you think I am being naïve? Has your animal research been useful? Do you think we should stop animal work completely on ethical grounds?


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One comment

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