Size

• Male and female boa constrictors vary in size. Females are typically larger, ranging from six to eight feet long, while males are usually five feet or smaller. Females also tend to weigh more than males. Female boa constrictors can weigh over 12 pounds; male boa constrictors rarely weigh more than eight pounds. According to "Boa Constrictor" by Laurel Lindemann (2009), this may be due to the fact that females give birth to live young. The larger size helps produce larger litters.
  
  

Appearance

• There are some slight differences in appearance between male and female boa constrictors. The male boa has a longer tail, caused by the added presence of the hemipenes, which is the reproductive organ for male boas. Male boas also have larger pelvic spurs than females. These can be felt by running your hand gently across the lower body of the snake. Males also have larger caudal plates than female boas.
  
  

Aggression

• Female boa constrictors tend to be more aggressive than males. Much of this has to do with the care of the young. While young are being raised, the female is more aggressive in defending her brood. Typically, males are only aggressive when hunting. There is little to no fighting between males over reproducing with a female. Males will search for miles in pursuit of a mate, but will not attack other boas that they come across.
  
  

Reproduction

• Boa constrictors sexually reproduce; the male uses his hemipenes to fertilize the eggs inside the female's body. The eggs completely develop inside the female's body and are birthed alive. The male uses more energy in reproduction than the female. He uses his pelvic spurs to guide both him and the female during reproduction. Females do not reproduce every year, but only when they are in top physical condition. Males may not reproduce every year either, but they typically reproduce more often than females.
  
  

Care of Young

• The male boa constrictor does not participate in caring for the young. Once reproduction is over, the male leaves. Boas in general are solitary creatures, and rarely live together. Female boas only live with their young until the young are developed enough to live alone. The female spends some time finding food for her young and protecting them from danger.