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 male Indian python in less than two years , his mate in less than three ; data on the <WSD>boa</WSD> constrictor about match this . 
Meaning of the word marked with <WSD> tags:  very large boa of tropical America and West Indies