What's the difference between mammalogy and mastology?

Mammalogy

Definition:

• (n.) The science which relates to mammals or the Mammalia. See Mammalia.

Example Sentences:

Mastology

Definition:

• (n.) The natural history of Mammalia.

Example Sentences:

• (1) From 1978 to 1988, 611 cases of breast cancer were seen by the Mastology Department of the Beneficência Portuguesa Hospital in São Paulo, Brazil.