Male and Female Largemouth Bass: Similarities & Differences

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A guy pick up a largemouth bass from the pond.

The appearance and behavior during the spawn are the main distinctions between male and female largemouth bass. Generally, female bass are larger than male (“buck”) bass. Also, male bass will squirt a white liquid during the spawn while the females expel eggs.

All across the country, freshwater anglers have an obsession with catching largemouth bass, and I can’t help feeling the same way. The differences between male and female largemouth make them even more exciting to catch. Knowing the differences helps anglers land more fish and protects the species for future generations.

How Can You Tell if a Largemouth Bass is Male or Female?

During the spawn, you can tell the difference between the genders by gently massaging their bellies. You’ll know it is a male if you see a white liquid squirt from the anal opening. If you see greenish/red eggs pour out, you’ll know it’s a female. 

You can also tell the difference by looking at the urogenital area on the fish’s underside. Males will have one opening, and females will have two. These holes look like small red dots and can be found on the belly of the fish, near the rear.

Once you locate the aperture, you can observe the area around them to be more sure. If the scaleless area around the opening is more of an oblong and oval shape, it’s likely a male. Females usually have a nearly perfect circle around the hole.

Perhaps the most challenging way to determine gender is to look through the water’s surface and guess based on the size of the fish.

Some of the only times it is possible to tell gender based on the eyeball test is once the spawn hits. Before they spawn, mature females’ stomachs grow larger because of the eggs inside them. Their fat stomachs are easy to see as they are sitting on beds.

The males are the smaller, more thin bass sitting near the beds. They’re waiting to fertilize and protect the beds once the eggs are laid.

Are Male or Female Largemouth Bass Bigger?

Generally, female largemouth bass are larger than males. Experts would say that if a bass weighs more than six pounds, you can assume it is a female.

They would also warn that if you kiss the fish and it kisses back, it was a female, but I’m not overly confident in that test.

Females have to be larger because they can carry and lay upwards of 7,000 eggs per pound of their weight. Their body must support all these eggs, so the larger the fish, the more they can carry.

Also, female largemouth bass usually live longer than males, so they have more time to grow.

Letting Go: A Huge Bass, Caught & Freed!

Do Largemouth Bass Change Their Gender?

According to a 2015 study, around 27 percent of largemouth bass throughout the Northeast had features of the opposite sex. For example, male bass would have eggs where they traditionally would have testes.

Experts say estrogen in the water affects largemouth bass, even in small doses. While it’s unknown if largemouth bass are intersex nationwide, many bass species in the Northeast are experiencing changes. 

Smallmouth bass and black sea bass are facing the most change.

Male Largemouth Bass Size

Mature male largemouth bass usually grow to a few pounds and are 14-18 inches long. Males mature faster than females, and it’s common to see a small male bass with a large female during the spawning season.

Posing with a big bass after a great catch

Male vs. Female Largemouth Bass Behavior

Males and females generally behave the same throughout the year. However, their instincts and behaviors change when the spawning season hits.

Spawning Season

Both largemouth males and females take part in the spawning process, and both are hungry during it. Their primary focus is to get eggs laid, fertilize them, and protect them until they hatch into fry.


Before the spawn officially begins in the spring, males will find and create a nesting area in sandy, shallow water. These small holes in the ground are known as beds. 

Males will use their tails to dig into the ground and create a suitable area for female bass to lay their eggs.

Once done, males stay near the bed and wait until a female chooses to lay her eggs there. 

In Spawn

During the peak of the spawn, it’s common for male bass to not eat for several weeks because they’re busy fertilizing and protecting eggs. 

I accidentally landed many male bass during the spawn because I’m targeting a female nearby. The males become so aggressive that they attack anything near their eggs.

Before the eggs hatch, females lay low, often near the beds, and stay in shallow water.

Post spawn

Immediately after the spawn, both males and females are lethargic. They stay in shallow water while they recover. They want easy meals that will build back their energy quickly.

As the days pass, bass will move to deeper water because of the warming air and water temperatures. While they move, both genders continue to feast. 

I enjoy fishing the post-spawn because the fish are aggressive and eager to eat larger baits. 

Largemouth Bass, glides in Rainbow River's cool 68°F water.

Out of Spawning Season

During summer, fall, and winter, male and female bass move into different parts of the water to feed and prepare for the spawn in the spring. Both genders are deep in the summer and feed in the mornings and evenings. 

In the fall, males and females enter a feeding frenzy to fatten up before the cold temperatures hit.

In the winter, both do their best to conserve energy and feed while waiting for the temperatures to warm so the spawn can begin.


Female bass will be larger than the majority of male bass you encounter. They mature later and need larger bodies to handle all their eggs. Both will be aggressive, but their differences become apparent once the spawn occurs. Males take on the protector role, while females look to lay their eggs and move on to the next stage.

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