ELi5: Rats seem to be the gold standard for behavioral lab experiments – why? Other than quantity, what makes rats good test subjects in relation to humans?
In: Biology
Rats are not the “gold standard”, The way choosing an animal for a test works is all animals are put in a sort of list from most to least sentient or important. For example, nonhuman apes would be at the top followed by non-ape primates, then dogs, rodents, etc.. all the way down to zebra fish and insects. Labs are required to pick the lowest animal on the list that can still produce a good result.
Although it would be more accurate to use apes for every single experiment, they often have to use the lowest mammal on the list, which just so happens to be rodents.
Obviously, this is very simplified, and the other people bringing up cost, space, intelligence and availability are also correct, lots of factors go into determining biological models
Realistically they are not. They are just what they use and it is accepted that they use them, which is one reason you should not pay much attention to attempts to link rat studies, especially behavioural ones, to people.
For a real laugh, look into autism research in mice. Seriously.
There are lots of different animals used as models for humans. A primate is closest to a human, but presents certain logistical difficulties. A fruit fly is much easier to work with, but less closely resembles humans.
Depending on what research you’re working on, you may want to use different animal models to suit your needs. Some things to consider include cost, maintenance, the time it takes to generate progeny, and in what ways the animal may or may not resemble what happens in humans. If you’re just looking at some genes which most animals share, it might make sense to work with fruit flies as they’re cheap and easy to maintain, it’s easy to work with their DNA, and they reproduce very quickly which is good for crossing genes into progeny. If you’re researching hearts or kidneys though for example, you may want a vertebrate animal like a fish or mouse or something. If you’re looking at behavior, you may want an animal that’s capable of more complex behaviors like a rat. If you need a much more complex model that very closely resembles humans, you may need a primate.
Also I think that since they are easy to breed, you can study how genetic traits transfer across generations pretty well.
Compared to the other responses this seems kinda niche but another reason the lab we got our data from used small rodents was their thin skulls. You could record their neuronal activity (using fluorescent calcium) without having to do any invasive operations.
Source: Wrote CS thesis in Neuroscience institute. Didn’t have anything to do with the experiments though so limited insight there.
Not sure it’s already been mentioned, but another reason to use rats is their lifespan. An average lifespan for a rat is right around 2 years. Two years is still practical enough to administer a drug on a daily basis and look for oncongenesis near the end of the rat’s life. You then can have a pretty decent idea (after examining all of the data) on whether or not a human may develop cancer if they were to take the same drug for a majority of their life. You wouldn’t do such a study in non-human primates because it’s completely impractical to administer a drug daily for decades at a time.
Mice far outnumber rats in research in general. For behavior experiments specifically, not sure. If rats are more common there, maybe because they’re smarter than mice?
It depends on what you are testing.
For example, Pigs make a better heart analog. Enough so that people can have the heart valve from a pig transplanted.
So much research has been done with them that you don’t need to worry about other variables and can just focus on certain things. Like if you wanted to see how certain genes affect smell in rodents you have a huge amount of previous studies showing good experimental setups so you don’t have to take as much of a time figuring out what to do.
There’s so many good reasons to use rats/mice in foundational medical research. For one they are mammals, so many basic biology points are there, you got all a lot of similarities in organs, and blood circulation.
Then there’s the unique properties of the animal itself, the ease of changing or creating new strains of animal to fit certain medical needs, the high turnover as a mouse usually lives at max 2.5 years, the ease of maintenance, and the simplicity of enriching their lives (remember, poor procedures and poor hygiene/enrichment leads to poor scientific data).
Those who work in the field know the vital nature of empathy and compassion for the animals sacrificing their lives in the pursuit of better medical outcomes. It takes a special breed of person to become an animal technician, gotta love animals (and most likely somewhat anti-social) and must be ready for crazy circumstances.
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