Today's whale watching tours gave us a rare opportunity. While observing a humpback whale repeatedly tail slapping, the tail was lifted high enough above the water for us to get a clear view of the genital area, allowing us to identify the individual as most likely a male.

Unlike some other whale species, humpback whales show very little sexual dimorphism. This means that males and females look remarkably similar from the outside, making it difficult to determine their sex during normal whale watching encounters

One of the few ways to identify the sex of a humpback whale in the field is by observing the genital area on the underside of the body. This is rarely visible, as it usually remains underwater, but during behaviors such as tail slapping, breaches, or rolls, a brief glimpse is sometimes possible.

Female humpback whales possess a distinctive hemispherical lobe, often described as being about the size of a grapefruit, located just behind the genital slit. They also have two mammary slits, one on either side of the genital region. Males lack this hemispherical lobe, and the spacing between the genital slit and the anus is generally greater.

However, even when this area becomes visible, determining the sex is not always straightforward. The viewing angle, distance, water conditions, lighting, and the brief duration of the observation can make interpretation challenging. In whale watching, opportunities to see these features clearly are rare, which makes observations like today's particularly exciting.