Once the males are lured by a female's pheromones, several males try to court one female female by rubbing their chins along her back. This is called a "mating ball."

Like all other snakes, red-sided garter snakes, are cold-blooded. During the winter, when the temperatures drop to below freezing, they hibernate for eight months.

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Source: National Geographic

Manitoba, Canada is laced with sinkholes that line its superficial limestone bed rock. Underground dens form here, attracting the snakes, who see it as the ideal spot for an 8-month snooze.

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Source: National Geographic

But space is limited. Thousands of snakes end up in dens as large as an average living room.

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Once spring arrives, thousands of the the red-sided garters slither over one another to emerge from their lairs, forming a carpet of quivering snakes.

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Source: Government of Manitoba

It's also peak breeding time: The males eagerly look for a female to mate with in the areas surrounding the den.

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Source: New York Times

In the huge heap of snakes, it can be tough for the males to recognize the females, even though they're longer and wider than the males.

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Source: Government of Manitoba

This is made even more interesting by the fact that the ratio of males to females is 10,000 to 1.

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Source: Government of Manitoba

The male-biased sex ratio is a result of the males pouring out of the den first and awaiting the females, who typically emerge over the course of a few weeks.

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Source: Government of Manitoba, National Center for Biotechnology Information

Once the males are lured by a female's pheromones, several males try to court one female female by rubbing their chins along her back. This is called a "mating ball."

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Source: New York Times

The male closest to the female copulates with her, leaving a gelatinous plug inside her body that blocks her reproductive tract for about two days, warding off other males.

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Source: Robert Mason, Christopher Friesane Oregon State University

Then, the female can slither away from the carpet of snakes, where she'll in feed and give birth later in the summer. One female can give birth to 40-50 young at once.

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Source: Robert Mason, Christopher Friesane Oregon State University

However, if the female rejects the male, she can prevent his sperm from fertilizing her eggs, a mechanism called "cryptic female choice." She simply waits for the smelly plug to dissolve and then mates with another male.

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Source: New York Times, Government of Manitoba

In September, the snakes return to their dens for the winter, where scientists think they spend the next eight months in hibernation once again.

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Source: New York Times

The largest gathering of snakes in the world woke up from a nap - and the photos are insane

Like all other snakes, red-sided garter snakes, are cold-blooded. During the winter, when the temperatures drop to below freezing, they hibernate for eight months.

Manitoba, Canada is laced with sinkholes that line its superficial limestone bed rock. Underground dens form here, attracting the snakes, who see it as the ideal spot for an 8-month snooze.

But space is limited. Thousands of snakes end up in dens as large as an average living room.

Once spring arrives, thousands of the the red-sided garters slither over one another to emerge from their lairs, forming a carpet of quivering snakes.

It's also peak breeding time: The males eagerly look for a female to mate with in the areas surrounding the den.

In the huge heap of snakes, it can be tough for the males to recognize the females, even though they're longer and wider than the males.

This is made even more interesting by the fact that the ratio of males to females is 10,000 to 1.

The male-biased sex ratio is a result of the males pouring out of the den first and awaiting the females, who typically emerge over the course of a few weeks.

Once the males are lured by a female's pheromones, several males try to court one female female by rubbing their chins along her back. This is called a "mating ball."

The male closest to the female copulates with her, leaving a gelatinous plug inside her body that blocks her reproductive tract for about two days, warding off other males.

Then, the female can slither away from the carpet of snakes, where she'll in feed and give birth later in the summer. One female can give birth to 40-50 young at once.

However, if the female rejects the male, she can prevent his sperm from fertilizing her eggs, a mechanism called "cryptic female choice." She simply waits for the smelly plug to dissolve and then mates with another male.

In September, the snakes return to their dens for the winter, where scientists think they spend the next eight months in hibernation once again.