The Importance of Pedigrees

By | April 28, 2018

The Fun Mouse: Mouse Information: The Importance of Pedigrees.

At first you come to this page and notice how long it is. Perhaps it is a bit intimidating. But then you realize how essential pedigrees MUST be if there is this much to write about their importance!

Obtaining a Pedigree

If a breeder doesn’t openly divulge a pedigree, this is a red flag. A good breeder will give pedigrees, with phenomenal tracking, with each and every mouse with OUT being asked to do so. A “breeder” that doesn’t do so is either hiding something, or disorganized. Either way, it’s not something you want to deal with. If they are disorganized, you know that the history you are getting on your mouse is likely inadequate at best, which does you no good at all. Don’t brush it off if a breeder talks about pedigrees casually. Any breeder worth anything knows their importance.

Why is a pedigree important for a pet-only adopter?

Many people that seek pet-only mice don’t think a pedigree is important. However, a pedigree is incredibly important for both breeders and pet-only caregivers! A pedigree will tell you a lot about your mouse and a lot about the breeder too! An animal can only be as good as the dedication a breeder puts into them. Therefore knowing the breeder is every bit as important as knowing the mouse.

A pedigree is far more than a piece of paper listing the ancestors of your mouse. It should be an adequate history of the lineage, including health, variety/genotype, date of birth, date of passing, among other important notes. You may look at that list and think “I only want a pet, why do I care about some of those things?” But ALL of them are VERY important to you, as a pet owner! Let’s go through them and discuss why they are so important.

Health History

One of the most important things for you to know is the health of the line you are getting. How healthy was the line in general? How often did they get sick and with what? At what age did they pass and what did they pass of? In this history you should be able to tell if there is some chronic problem. Is there something inherited? Is there a disease spreading in their mousery? This health history will also tell you if they bring their mice to a vet, which is incredibly important. ALL breeders should have an on-call vet! Mice get sick, just like people. Also like people, mice need adequate medical care. If a breeder doesn’t care enough to keep their mice healthy and seek outside help when needed, this is a HUGE red flag…. RUN! We all have to draw the line somewhere when it comes to finances, but a breeder knowingly takes on the responsibility to adequately care for their mice, which means taking them to a vet when needed. While there are some things we can cure without a vet, a breeder needs to know what they can handle at home and what needs outside medical attention. Vets are there for a reason. If a breeder can’t see that, they are depriving their mice of proper care. If they are ignorant to the value of vets, also consider that they are likely ignorant of a lot of other mouse care aspects too! A good breeder seeks any and all tools to help their mice prosper. If a breeder doesn’t feel their mice are worth a vet, they can’t possibly care about what they are breeding. This means less than healthy mice, and NOT good pets. If they don’t want to keep their mice alive and healthy, they don’t view their mice as pets at all, and this isn’t the type of “breeder” you want to adopt a PET from. If a breeder doesn’t think mice are worth the cost of a vet because the mice are so cheap to obtain, they don’t value their mice any more than money, which smacks of back yard breeder. Also consider that size doesn’t matter. Just because they are small and easy to obtain doesn’t mean they are worthless or disposable. If that were the case, then people are disposable too. People are easier to seek and smaller than elephants. Does that mean we are worth less than elephants? Is your life worth less than an elephant? A life is a life.

While evaluating the pedigree for health issues there are a couple things you need to keep in mind.

An important thing to know is that NO line is clean. NONE. Every single line has a fault. This means that you should not necessarily freak out when you see something negative on the pedigree in relation to health. Just know what the problems could potentially be and analyze if this is something you are willing to deal with. You should, however, be concerned about too many things coming up on the pedigree regardless of what they are. Did most the mice have tumors? Did most the mice have a respiratory infection? While things will come up when breeding mice, there should not be an overwhelming issue either. If there is, the line likely should have been stopped long ago and the breeder should not be letting them out of their mousery. Just the same, if the pedigree is too clean, the breeder is hiding something and this too is a huge red flag. If a breeder tells you that their mice have -never- had a tumor (for example), they are LYING or they are not tracking their lines well enough (or, they are a brand new breeder, and in which case they don’t have adequate history). Tumors happen. They should not happen to the majority of the mice, but a tumor here and there is completely normal. Just like with people. Look at a healthy line of people. There will be some with health issues. It just happens. But if a breeder denies it ever happening, they are lying or they are not tracking their lines adequately. This makes any health history you receive from them completely useless because you can’t trust it. If a breeder lies or doesn’t tell you the whole truth, it’s the same as no pedigree at all and you have no way of knowing the health of the line you are getting.

Looking at the mice the breeder has is NOT an adequate indication of how healthy their mice are. A breeder can easily ‘stash’ mice away so they are hidden from your sight and you will be none the wiser. Also, the animals that a breeder has in their care are likely a VERY small percentage of the mice in the line, therefore you cannot adequately judge the health of the overall line by them alone. Perhaps most of the line dies at 2 months of age, and all you are seeing are the very few that make it. You don’t know any better just by looking. Perhaps the breeder claims that they adopt out all/most their old mice and that is why they don’t have any older ones, yet the reality is that the older ones are long passed on. You don’t know any better. Perhaps the breeder culls any mouse that looks remotely sick so it doesn’t give their lines a bad mark. This would make it so you only see the good but are oblivious to what is actually happening. There are so many things a breeder can hide and even the most seemingly sincere person can easily lie to you. Judging someone on personality alone is exactly how people get conned all the time. Perhaps you think that someone has nothing to gain by conning you about some mice. That isn’t true. People have all kinds of motives. It makes people feel good when others look up to them, even when it comes to being a mouse breeder. People can also make money off mice (back yard breeders only). Even charging $1 for a mouse adds up fast! You may think it’s minimal, but it’s not. As a comparison to help put this into perspective, many websites make money by people clicking ads. Every click pays out -only- between 5-11 cents. A good website can easily make THOUSANDS a week from just those few pennies alone. Still think your $1 doesn’t count? Lastly, some people are just plain weird. Who knows their motives. I’m sure we’ve all seen people do far stranger things for far less.


Most pet-only caregivers dismiss this immediately. All they want is a healthy mouse regardless of looks. However, if a breeder knows varieties and genotype, this tells you a lot about them as a breeder and the line (including health)!! If a breeder has no idea about what varieties their mice are (which includes them not being able to accurately identify them. i.e. just because they give a mouse a label, that doesn’t make it correct), they have not done enough research to be a good breeder. It makes one question if they have done ANY research at all, including health research. ALL breeders should be working for a goal. Breeders NEED to be advancing mice with each generation, not going backwards or idling. They should have honor and good ethics. If they are not breeding to advance the species as a whole, which includes conformation, they should not be breeding at all!

There are some varieties of mice that are LETHAL when bred. A breeder NEEDS to know these varieties for the health and safety of their mice. If they put no care into knowing these varieties/genotypes, they have no business breeding whatsoever.

Some varieties are more prone to health problems than others. Does the breeder know these varieties? A breeder that simply says “I don’t breed any of those varieties” it isn’t an adequate answer. If they don’t know what those varieties ARE, then they don’t know if they are breeding them! Do you want a mouse from a breeder that has no idea what varieties are more prone to health problems?

If a breeder knows genotype, this tells you a LOT! This means that they know what they are doing and they understand inheritance. A breeder needs to know genetics for several reasons:

1. All breeders should be breeding for a goal, like stated before.
2. Knowing varieties isn’t enough to identify mice with lethal genes or genes that are linked to health issues. Some can be hidden and only good tracking and knowledge of genetics will tell them.
3. A breeder that knows genetics knows inheritance. This plays a direct role with health tracking. If they don’t know the genotype of their mice, they don’t understand how health is inherited either. This makes it completely impossible for them to breed healthy mice! If you don’t know how it works, you can’t breed for healthy mice because you don’t have the knowledge to do so! Even if you want a pet-only mouse without any concern for appearance, getting mice from a breeder that has a thorough understanding of genetics and varieties is incredibly important!

Date of Birth

If a breeder isn’t tracking something as simple as date of birth for every mouse in the line, how do they know when their mice are of breeding age and too old to breed? Are they breeding these mice at ages they shouldn’t (which can cause health issues for mother and offspring)? How do you know how old your mouse is? I your mouse has a birth date, but none of the others do, what makes you think they the breeder didn’t just guess? How do they know the life span of their lines of they don’t track DOB? If a breeder can’t track something as simple as date of birth, none of their notes are worth anything.

Date of Passing

Does the breeder know when their mice have passed on? This will give you a rough idea of how long your mouse should live. Some lines only live a couple months, especially those from bad “breeders.” Knowing when their ancestors passed can also help tell you how well the breeder is tracking their lines in general. If they adopt mice out, they should be tracking every one of them. They should know when they passed, and why. If they don’t, then they don’t have an adequate history of their mice and you can’t possibly know the health and longevity of the line which is a direct reflection of what to expect in your mice.

With that said, if a breeder does adopt out to the general public and they claim to know EVERY date of passing and why, they are VERY likely lying to you. Even the best breeders loose contact with some adopters for one reason or another. It’s very sad and it shouldn’t happen, but that’s the reality. This is why most breeders refuse to adopt to the general public. A breeder should be able to track roughly 90% of their mice though. In summery, you don’t want to adopt from them if they: 1, Claim to track 100%, because they are probably lying (or they don’t adopt to the general public, in which case you would not be adopting from them). 2, If they track significantly less than 90% it’s because they are not a good judge of character (adopting to the wrong people that don’t follow through with updates), they don’t have an adequate adoption policy, and/or they don’t follow up with their adopters, etc.

Feeder “Breeders”

A feeder breeder is not where you want to get a mouse from. There is no way to adequately track the lines when the offspring is not living very long due to them being eaten. This means you have basically no health history at all. Most feeder breeders also have one goal in mind; quantity. It is absolutely impossible to breed for quantity and quality. A mouse needs to be able to produce many offspring in a litter to make them “worthwhile” for a feeder breeder. Unfortunately this goes completely against nature and therefore both mother and babies suffer. A mouse should only have ~5 pups per litter in order to adequately feed them. Most feeder breeders strive for ~20 per litter. Nutrition for these babies is like only having 5 sandwiches for a meal and forcing 20 kids to share them. No one gets the nutrients they need to thrive because there isn’t enough to go around. A mother can only produce so much milk. She can’t defy nature. If the pups get less than adequate nutrients growing up, their health will suffer. The most critical time in a mouse’s life is from conception to weaning. Deny nutrition then and you are denying good health later. Lastly, most feeder breeders will breed females to death, literally. They start them young, breed them back to back, and often “retire” them when they stop producing (which usually means death because she would be taking up needles space that a producing female could fill). This means that ALL the mice suffer because mom isn’t able to regenerate. If she is completely drained of nutrients form being over worked, she has none to give to her babies. Babies from mothers that have back to back litters will clearly show a decrease in health and longevity. Even a single back to back litter will suffer. Almost always the babies from the second, younger litter, will die sooner, suffer health issues, be prone to more tumors, etc before the older litter. This is for no reason other than mom isn’t healthy enough to raise them despite how she may look. Do you want to deal with the consequences of this? More importantly, do you want to watch your mouse suffer those consequences??

Note that not all feeder breeders will breed as poorly as the examples given (which is why I said “most,” not “all”). However, it doesn’t erase the fact that it is impossible to breed feeders and track lines for health because they are feeding the mice off before their expected passing. You can’t track what isn’t alive.

Pet Shop “Breeders”

For the same reason you don’t want to adopt from feeder breeders, you don’t want to adopt from those that breed for a pet shop. It is completely impossible to track lines when selling to a pet shop, no matter how “good” they claim the pet shop is. Any breeder that tells you that they collect ALL the adopters information and follow up with them is lying. The scale of adoptions is far too large and the idea of a pet shop employee (or even owner, friend, etc) being able to track that information is laughable. It’s hard enough for a reputable breeder that does their own adopting out to track their lines (as noted above). Adding more factors into that, especially when it comes to a business, will ONLY cause more room for error and inadequacies. A respectable breeder will never adopt through a pet shop, not even their “extras.” A reputable breeder has adequate plans for their “extras” which includes secure ways to track them their entire lives. A reputable breeder will also NEVER trust a pet shop to screen homes for their precious babies. Pet shops are a business and their bottom line is money, otherwise they would not be in business. This isn’t necessarily because they are callous, but they MUST make a profit or they wouldn’t exist. That’s the hard facts. You cannot make a profit breeding mice ethically. It’s flat-out impossible. A pet shop doesn’t have the resources to screen homes properly. This would take time, which would take money. Having an employee screen an adopter adequately would cost far more (in hourly wages) than the animal costs. This means a profit loss, which isn’t acceptable because it would cause them to go out of business. A business also has a hard time being able to turn down adopters because of the flack they would get. If a pet shop turns down an adopter, the adopter then screams to anyone and everyone that will listen, which brings a lot of bad press to the pet shop. Pet shops cannot risk that from a business standpoint. If an adopter doesn’t care about a pet shop finding the babies a good home, they don’t care about their mice as PETS, and that isn’t something you want since you are looking for a pet mouse.

Online Pedigrees

While it isn’t a necessity, seeing online pedigrees are a great resource for you as an adopter if the pedigree program is adequate. A standard pedigree of 4 generations can tell you something about the line, but not a lot. A pedigree will not show you siblings of all the parents in the line. Considering that a mouse can have MANY siblings, only knowing the history of one isn’t a lot. Perhaps the specific mouse in your pedigree is doing well, but most/all his/her siblings have suffered illness. This could still be passed on to your mouse even though the direct parent isn’t effected yet. Also consider that a generation can be as minimal as 3 months. All the mice on the pedigree you get might be under a year old! That doesn’t tell you much at all! Thanks to adequate online pedigrees, being able to look further back in the history AND being able to look up the siblings of all the mice in the line is HUGE! This will give you a LOT of health information, as well as information on how well the breeder tracks their mice. It also shows that they are open about their mice, both the good and the bad.


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