How Do Frogs Mate?

How frogs mate may seem complicated to understand since frogs do not have external genitalia and only a few distinguishing factors can help differentiate male frogs from female frogs. 

Frogs reproduce sexually by amplexus through external fertilization. Female frogs can lay 2 to over 25,000 eggs once or twice per mating season depending on the species.

Let’s dive into exactly how frog mating works, how frog mating happens, that time of year it occurs, and why male frogs may latch onto just anything during mating season.

1. Frogs Mate Sexually

Frogs reproduce sexually by amplexus through external fertilization, meaning a male and female frog are required for reproduction. The female frog releases her eggs into the water and the male frog simultaneously releases sperm cells to fertilize the eggs.

Frogs do not have external genitalia and only a few distinguishing factors can help differentiate male frogs from female frogs. Male frogs generally have vocal sacs they use to call females during mating season, they can be smaller or larger than female frogs depending on the species, and their thumbs may be enlarged during mating season (nuptial pad). Female and male frogs may also be of different colors (Lambert et al 2017).

Since frogs do not have external genitalia like humans, how frogs mate may be confusing to people. This may be one reason for the number of misconceptions about frogs, their sexuality, gender, gender reversal, and sexual preferences.

2. Frogs Mate by Amplexus

During mating season, male frogs use their vocal sacs to call female frogs of the same species to their location in order to reproduce. This generally takes place in the Spring in temperate climates, or during Rainy, Wet, or Monsoon seasons in some climates, or all year round in the Rainforest.

Once the male frog has attracted a female mate, the couple will generally get into an inguinal or axillary amplexus position in order to reproduce. Most often, the male frog climbs onto the female’s back and clasps her around the waist (CTNF).

Amplexus stimulates the female to lay eggs and can last a few hours to a few months depending on the species of frogs. Frogs have several amplexus positions but here are the two main types of amplexus frogs may use:

  • Inguinal Amplexus: Occurs when a male frog clasps the female frog around her waist (inguinal region) using his forearms.
  • Axillary amplexus: Occurs a male frog clasps the female behind her forearms (axillary region).

Once male and female frog of the same species are in amplexus, and in water, the female releases her unfertilized ovum into the water while the male simultaneously releases sperm cells to fertilize them, rendering the eggs zygotes, or newly fertilized eggs.

3. Many Frogs Mate by Trial And Error

During mating season, male frogs may accidentally mount another male, another species, a dead female, inanimate objects, or multiple frogs when there is competition for few females. Male frogs go through a trial-and-error process looking for females of the same species that have not yet reproduced.

“The reproductive strategy for male B. bufo may be to clasp quickly every moving animal of similar size and then determine whether it is a female.”

Mollov et al. 2010

Many scientific studies found that frogs attempt to mate with male frogs, other species, and even inanimate objects. (Simović et al 2014). A frog’s search for a mate is often a trial-and-error endeavor as they “attempt to clasp practically any moving object”  (Wells,  1977; Berven, 1981). But the male frog moves on once it realizes what it is holding is not a female it can reproduce with.

4. Frogs Mate During Mating Season

Most frogs reproduce in early Spring in the Northern Hemisphere which can take place as early as February to May depending on the location and climate. In the Southern Hemisphere, or where the climate is consistently warm and humid, frogs can reproduce at any time of the year.

Frogs generally like to reproduce when it is rainy and wet. Rain water replenishes dried ponds, lakes or bogs, providing more space for them to lay their eggs and for their tadpoles to thrive. Depending on where the frogs are located, Monsoon or Rainy Seasons may dictate when frogs reproduce.

Most frogs can reproduce once they are over the age of 3 or 4. When the Mating Season begins, adult males find the pond where they were born, or an ideal location to reproduce, and call out to attract female partners. They fill their vocal sacs with air and expel loud sounds that can be heard up to 1km away depending on the frog species. Each frog species has a unique call to attract females of the same species.

Learn more about when frogs mate in our complete guide that includes different locations.

5. Frogs Do Not Remain With Their Mate

Contrary to popular belief, frogs are generally solitary animals. They do not remain with their mate after reproduction. Adult toads generally leave the pond where they laid their eggs to return to land, and many frogs species are known to even eat their tadpoles. Large frogs will also willingly eat smaller frogs.

Frogs generally only reproduce during mating season to ensure the survival of their species. Although pictures of frogs kissing are cute, they are generally staged or rare occurrences that are not specifically demonstrating affection in the eyes of the frog. So enjoy the cuteness of photos of frogs kissing, but keep in mind it’s generally not because they are in love.

More About How Frogs Mate

Common Questions About How Frogs Mate

Can male frogs have babies? Male frogs cannot have babies alone, however there are some species of frogs where the male gestates, carries or watches over its young. This is a very rare phenomenon and only affects few frog species including Suriname Toads, Gastric-Brooding Frogs and African Bullfrogs.

Can frogs have babies without mating? Frogs cannot have tadpoles, froglets or baby frogs without mating. Frogs reproduce sexually and therefore a male and a female frog need to be involved for baby frogs to be born.

Where do female frogs release their eggs? Female frogs release their eggs in permanent or temporary bodies of freshwater with little to no current depending on the species. These may include ponds, lakes, streams, puddles, marshes, bogs and fens.

How long do frogs take to mate? Mating can take a few hours to a few weeks depending on the frog species. Some frogs can take a few weeks to find a mate, others may remain in amplexus for a few minutes to over 48 hours. Mating generally stops after mating season depending on the species.

Do frogs stay with their eggs? The vast majority of frog species do not remain with their eggs after reproduction. Some frog species do, however, remain with their eggs including a few types of Dart Frogs and Suriname toads.

How old are frogs when they breed? Most frogs can generally reproduce after 1 to 4 years depending on the species.

When frogs mate who is on top? The male frog positions himself onto of the female frog during amplexus to mate. The female frog releases her eggs while the male frog simultaneously fertilizes them.

Sources

Berven, K.A. (1981): Mate choice in the wood frog, Rana sylvatica. Evolution 35: 707–722.

Mollov, Ivelin & Popgeorgiev, Georgi & Naumov, Borislav & Tzankov, Nikolay & Stoyanov, Andrey. (2010). Cases of abnormal amplexus in anurans (Amphibia: Anura) from Bulgaria and Greece. Biharean Biologist. 4. 121-125. 

Lambert, Max & Tran, Tien & Kilian, Andrzej & Ezaz, Tariq & Skelly, David. (2019). Molecular evidence for sex reversal in wild populations of green frogs (Rana clamitans). PeerJ. 7. e6449. 10.7717/peerj.6449. 

Wells,  K.D.  (1977): The social behaviour of anuran amphibians. Animal Behaviour 25: 666–693