Why so many eggs?

Learn why there are so many tadpoles in your pond…


Mating

During spring, male and female frogs arrive at ponds to mate. In some places you will see a pond full of frogs, like in the picture below!

One important way for frogs to communicate with each is singing. There are different types of calls frogs can make and some are used for finding a mate. Click below to listen to some croaking calls (courtesy of Darcy Kelly):

Chirping
Growling
Laevis Advertisement Call
Male answer

This photo shows how frogs mate. Notice the female is a different colour to the male.


Frog spawn

Once courtship has taken place, the female  lays huge numbers of eggs (up to 4000) and the male fertilises them as they are laid.

These eggs are called frog spawn and are laid in clumps, with a protective jelly layer surrounding the fragile developing tadpole. The jelly also helps the frogs pawn to float on the surface of the water.

Look closely at this picture and you’ll notice its completely full of frog spawn!

Once the eggs are laid and fertilised, both the parents leave the pond. The tadpoles develop without help from their parents. Laying lots of eggs is therefore a good idea when there is no help to survive from the adult frogs. Other animals like birds have only a few babies at a time and spend time and energy looking after them.


Who eats tadpoles?

It may seem strange to put so much energy into laying thousands of eggs. But frogs have good reason for doing this- pretty much everything wants to eat a tadpole! Just like this kingfisher…

Many animals will also eat frogspawn or indeed baby froglets. So at each stage of a frogs life danger is around every corner. Insect nymphs(like the damselfly nymph below), newts and fish will all gobble up a tadpole if they get the chance!

Animals that eat tadpoles and frogs are predators. The tadpoles or frogs are therefore called the prey.

Predators of tadpoles include:

  • birds
  • newts
  • dragonfly larvae
  • fish
  • great diving beetle and its larvae

Click here to find out more about tadpole predators. 

Ducks have even been reported to gobble up frogspawn! Foxes and badgers will also eat little froglets as they leave the pond.

Check out this massive diving beetle larvae munching on a tadpole!


Lots of eggs

If everyone wants to eat your babies and you are not there to protect them, its a good idea to lay lots of eggs! Many tadpoles, means it is more likely to have some willsurvive.

It is thought that only 1 in 50 eggs makes it to become a froglet without being eaten. That’s not good odds!

At each stage in the picture below, many tadpoles are eaten. So not many surviving froglets leave the pond.


Care from parents

When a mother or father looks after its offspring for some or most of its life, this is called parental care. The parents are caring for the offspring or babies. This means feeding them, sheltering them and protecting them from harm or predators, like this blue tit with its chicks.


Some animals do not look after their offspring.

Plants cannot physically look after their seeds, so produce lots. They do not care for or protect these offspring. Less of these offspring will therefore survive. Producing lots of eggs means that at least some of these offspring will survive, like this oak tree with lots of acorns, or a butterfly laying lots of eggs like these on a leaf.


Other animals give a lot of care and protection.

For example humans, some other mammals and some birds  have only a few offspring. This means parents can focus their effort into making sure those offspring survive.


Media credits under creative commons licence: Frogs in pond-Trevor Rickard; Frogs croaking- Benboncan@Freesound.org; Frogs mating-Piet Spaans; Frogs mating and spawn- Thomas Brown; Pond full of spawn-Piet Spaans; Kingfisher- Pierre Dalous; Diving beetle larvae eating tadpole-Gilles-San-Martin; fox cubs- Su May; duck with ducklings- Kim Taylor; Acorns- Everly Simack; butterfly eggs-Волков Владислав Петрович; blue tit with chick- David Howes.