Male and female bottlenose dolphins are strikingly similar in appearance, though males are typically larger. They have similar lengths, but males typically weigh about twice as much as females, so they're noticeably rounder. This is because females reach sexual maturity earlier than males do, giving them less time to grow. But size isn't the only difference between the two sexes.
The Key Differences
While an adult male bottlenose dolphin is typically between 96 and 150 inches long, a female is usually between 89 and 144 inches long -- a negligible variance. But males typically weigh around 1100 pounds, females only around 550 pounds. The other most notable difference between the two sexes is their reproductive behavior. Bottlenose dolphins are promiscuous, and males court females who are in estrus by nuzzling, snapping his jaws and posturing. In other cases, a group of males work together to steer a female in estrus away from her home range.
Tom Ryan is a freelance writer, editor and English tutor. He graduated from the University of Pittsburgh with a degree in English writing, and has also worked as an arts and entertainment reporter with "The Pitt News" and a public relations and advertising copywriter with the Carnegie Library of Pittsburgh.