Sentence:  The best way to determine the correct figure ( in captives ) is by direct observation of pairs isolated from birth , a method that produced surprising results : maturing of a <WSD>male</WSD> Indian python in less than two years , his mate in less than three ; data on the boa constrictor about match this . 
Meaning of the word marked with <WSD> tags:  being the sex (of plant or animal) that produces gametes (spermatozoa) that perform the fertilizing function in generation