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What is it called when a female animal turns into a male?

Published in Animal Sex Change 3 mins read

When a female animal turns into a male, this biological phenomenon is called protogyny. It is a specific form of sequential hermaphroditism, where an organism changes its sex at some point during its life cycle.

What is Protogyny?

Protogyny refers to the condition in which an animal is born or matures as a female and then, later in its lifespan, transitions to become a functional male. These animals are often referred to as protogynous hermaphrodites. This form of sex change is a natural evolutionary strategy observed in various species, primarily to maximize reproductive success within specific ecological or social contexts.

Understanding Sequential Hermaphroditism

Protogyny is one of the two main types of sequential hermaphroditism, a remarkable biological process where an individual changes its sex over the course of its life. Unlike simultaneous hermaphrodites, which possess both male and female reproductive organs at the same time, sequential hermaphrodites experience a distinct shift in their sexual identity and function.

There are two primary forms of sequential hermaphroditism:

Type of Sequential Hermaphroditism Description Example
Protogyny Female first, then changes to male Wrasses, Parrotfish, certain Groupers
Protandry Male first, then changes to female Clownfish, some Oysters, certain Anemonefish

Protogyny is generally considered a more common form of sequential hermaphroditism in fish compared to protandry.

Why Do Animals Exhibit Protogyny?

The ability to change sex is often an adaptive advantage, particularly in social structures or environments where an individual's reproductive success is influenced by its size, age, or social status. For protogynous species, this transition often occurs due to:

  • Size Advantage: In many species, larger males are more successful at defending territories, attracting mates, and securing reproductive opportunities. By starting as females and reproducing when smaller, individuals can then transition to male when they are larger and can better compete for mates.
  • Social Hierarchy: In some social groups, a dominant male controls access to a harem of females. If the dominant male is removed or dies, the largest or most dominant female may change sex to take over the male's role, ensuring the group's continued reproduction.
  • Resource Allocation: Switching sex can allow individuals to optimize their reproductive output based on the energy costs associated with producing eggs (female) versus sperm (male), or the effort required for parental care.

Examples of Protogynous Species

While found in various animal groups, protogyny is particularly well-documented and prevalent among certain fish species. Some notable examples include:

  • Wrasses (Family Labridae): Many species of wrasses, such as the bluehead wrasse, are classic examples of protogynous fish. In these species, all individuals begin as females, and some later transition into larger, dominant males.
  • Parrotfish (Family Scaridae): Similar to wrasses, many parrotfish species exhibit protogyny. They play a crucial role in coral reef ecosystems by grazing on algae.
  • Groupers (Family Serranidae): A number of grouper species, including some economically important ones, are known to be protogynous hermaphrodites. They often live in social structures where the largest female may transition to male.
  • Gobies (Family Gobiidae): Certain goby species also display protogyny, adapting their sex to environmental and social cues.

These examples highlight the diverse ways in which animals utilize sex change as a successful reproductive strategy.