Hermaphroditic Teaser “Mare”
A stud farm I once visited was using a hermaphrodite mare as a teaser, with none of the problems of having a stallion (i.e., no problem with mares in foal to the teaser stallion should he escape). How can you tell if a mare is a hermaphrodite (what does she look like, and what is her behavior like)?
AWhat you are looking for is a "male pseudohermaphrodite." This anomaly is an animal with the outward appearance of a mare, but with testes instead of ovaries. The behavior is that of a stallion. The testes are almost always inside the abdomen, but the external genitalia is the key. The usual pattern is an overdeveloped vulva and clitoris that resemble the glans penis of a male. You might look a long time, as these horses are not very common.
Another good potential teaser is a mare with a granulosa cell tumor of the ovary, which frequently causes stallion-like behavior.
One word of caution; some of these animals become aggressive and can be difficult to