We all know that different blood types exist, and most of us know what our own type is. There are four human blood types (O, A, B, AB), and each of those can be positive or negative, giving eight variants total. Eight types…for all of earth’s 7+ billion people.
But did you know each animal species has its own set of blood types? And that some species have way, way more complicated blood systems than humans?
Cattle: 11 different basic blood types (A, B, C, F, J, L, M, R, S, T and Z). The B group has over 60 antigens*. That’s a huge number of unique blood types!
Horses: There are over 30 blood groups in horses, of which only 8 are major systems. Each blood group has at least two allelic* factors (for example, the A blood group has a, b, c, d, e, f, and g), which can be combined in all combinations (Aa, Afg, Abedg, etc), to make many different alleles. This means that horses can have around 400,000 different combinations, allowing blood testing to be used as an accurate method of identifying a horse or determining lineage.
Cats: Domestic cats have just three blood types – A, B, and AB. Almost 90% of cats in the U.S. have type A blood, while some exotic or unusual breeds like have type B. Type AB is very rare, and is found in mixed breeds. Cats, like humans, must have their blood type matched with the donor blood.
Dogs: 8 blood types (types 1-8) have been internationally recognized in canines, and each type can be positive or negative. Types 4 and 6 appear in 98% of dogs. Dogs that are DEA 1.1 positive, which is 33 to 45% of the population, are universal recipients, meaning they can receive blood of any type without a reaction. Dogs that are DEA 1.1 negative can be considered to be universal donors
*What is an antigen? An antigen is any substance that causes your immune system to produce antibodies against it. This means your immune system does not recognize the substance, and is trying to fight it off. Antigens are what make it so important to match transfused blood with that of the recipient. If a different blood type were given, the body would see the antigens on the new blood cells as a foreign substance and would destroy them.
*What an is allele? An allele is an alternative form of the same gene, or in this case, blood type. The type of allele determines the blood type.
Those are very, very basic definitions. Blood type falls under genetics, a field which can get very scientific very quickly!