11 Animals That Can Change Gender

Gender isn’t always binary. Mother Nature doesn’t make gender a choice between one and another. In fact, in the animal kingdom there are many creatures that walk the line between male and female, changing gender based on their environment, availability of partners, and other biological needs. Others, still, display characteristics of both male and female creatures of their species. Here are 11 animals that can change their gender!

Parrotfish
Parrotfish always travel in groups. These groups (as they are fish, they’re called “schools”) are always led by a dominant male, followed by many female parrotfish. However, these female parrotfish are actually not what they seem. They are, in fact, deemed “secondary males”. This means they display all the characteristics of a female fish (including a reproductive system), but if the dominant male of the school passes away or is incapable to perform their role as a leader, one of these “secondary males” will change their gender and become the primary male!

Clownfish
They’re bright orange, they’re cute, and they’re famous thanks to “Finding Nemo” and “Finding Dory”. Similarly to the Parrotfish, Clownfish can change their gender if the leaders of their group are no longer capable to perform their duties. Schools of clownfish have a large male and an even larger female. The rest of the fish in the school are smaller, immature males. If the female dies, the large male will become female, and the largest “immature male” will become the mature male of the group of fish. This means that a single clownfish can (potentially) change their gender twice over the span of their lifetime.

Banana slugs
It’s bright yellow. It can grow up to 10 inches long. Of course it’s name is Banana Slug! These wormlike mollusks are what is called “simultaneous hermaphrodites” which means that unlike Clownfish (which are sequential hermaphrodites), they display both male and female traits (and have male and female organs) at the same time.
Although they are capable of self-fertilization, most banana slugs usually mate with a partner. When they mate, they both produce sperm and eggs. At the end of their mating, they both have fertilized eggs that they usually deposit under leaves or logs. One mating process – double the offspring!

Hawkfish
These vibrantly colored fish live in extremely large groups. And, just like clownfish and parrotfish, they can change their gender when the circumstances call for it. However, if in parrotfish and clownfish schools this usually happens because the male or female leader of the group dies, when it comes to Hawkfish, the gender switching happens when the school gets too big.
Schools of hawkfish have one male and many females. If one male has too many females in their group, the largest will become male, and the single school of hawkfish will split into two equal, but smaller schools of hawkfish.
Furthermore, the male hawkfish can revert back to being female if a larger male contests them or if the female population dwindles and additional females are needed for survival.