The phrase "mating pair" refers to two animals or organisms that come together for the purpose of reproduction. They usually have different genders and engage in activities to produce offspring. Full definition
They're commonly found in mating pairs, ready to release eggs. (divecentralgili.com)
But because all living ferrets share the same ancestry at a kinship level between first cousins and siblings, it very difficult to choose mate pairs. (reviverestore.org)
Other factors, including size and timing of return to fresh water, also determined mate pair reproductive success. (sciencedaily.com)