How to Tell Males and Females Apart
Cetaceans have their reproductive organs and teats hidden inside “slits” near their abdomen. This makes it hard to tell males and females apart just by simply looking at them.
One thing you can do to tell them apart is to check the “slits” near their abdomen. In males, the “slit” and the anus are vertically separated, while in females, the “slit” is connected to the anus, and they have another pair of shorter “slits” that conceal their teats.
However, in some species males also have the shorter “slits” with teats, which makes it hard to tell the males from the females.
Male or female?
Common bottlenose dolphins
The male is shown on the right, and the female is shown on the left.
Males have a long “slit” and an anus which form a line like an exclamation point “!”.
Females have a pair of shorter “slits” beside the long slit.
Killer whales
The male is shown above, and the female is shown below.
Male killer whales have dorsal fins which can grow as high as 2 meters, while the females have dorsal fins which are curved, making it easier to tell them apart. In general , male toothed whales are larger than the females.
Humpback whales
The male is shown on the right, and the female is shown on the left. Female baleen whales are larger than the males. Male humpback whales are said to sing “songs” to attract females.
Narwhals
The male is shown below, and the female is shown above. The “tusk” is the left, upper canine.
In male narwhals, the tooth can grow as long as three meters, piercing the upper lip.
Narwhals only have two upper teeth, and the females do not grow their teeth like the males do. Instead, their teeth are buried in their upper jaw.
However, on rare occasions, we can find female narwhals with an elongated tooth or males with two protruding teeth.
Ginkgo-Toothed Beaked Whales
The male is shown below, and the female is shown above. Only mature male Ginkgo-toothed beaked whales develop a pair of lower teeth like Stejneger’s beaked whales. Although females develop teeth, they remain covered beneath the gums, so it is hard to tell by looking at them.