Film | Secret Lives of Frogs in My Garden Pond | Discover Wildlife

From spawn, to tadpole and finally, frog, the early lives of frogs is fascinating. Watch the metamorphosis in my garden pond.

To capture the secret lives of frogs, I turn the spotlight on my garden pond and film the process from spawning, to hatching and finally, those first, frog hops. The common frog species, or Rana temporaria, can be found across the UK. They share my pond with an array of species, including toads, newts and a wide number of invertebrates.

Frogs in spring

Each spring frogs migrate back to my pond to breed in huge numbers. You can usually hear their croaks before you see them. It's interesting to see how they make these loud croaks, but literally holding their breath and moving the air to and fro. The males are so fired up they can sometimes almost drown the female as they fight to latch on to her and it can be quite dangerous as she gets pulled under in the frenzy - some even drown! In the confusion toads, also at the pond to mate, accidently join in and the fights between them can be dramatic!

Toads v frogs

The species are often confused, (and as this film shows in the frenzy of mating even the toads and frogs themselves get confused!) but generally frogs are smaller and have longer legs, with smoother, slimier-looking skin than toads, which are stouter and have drier warty skin. Also their spawn is completely different: toad spawn is laid in long strings of eggs rather than in balls. 

Tadpoles

The eggs are laid in their thousands, encased in a protective jelly filled with nutrients. The male sprays these with his sperm. The spawn, which expands in water, is there to feed the tadpoles during their first dates, and is attached to pond weed to prevent it from sinking to the bottom. It's incredible to watch the process as they egg cell divides and slowly a tadpole develops, ready to break free from the jelly. At this stage they eat just algae and plant matter, but now they undergo a remarkable metamorphosis, losing their feathery gills and growing back legs, then growing front ones. Their diet also changes and they begin to consume water fleas and other invertebrates. Sometimes, if conditions are too crowded, they even eat each other!

Predators

Although there are now thousands of tadpoles, few of them will make it to adulthood. Tadpoles are vulnerable to predators, including lesser diving beetles, spiders and backswimmers - a beetle that swims upside down! This creature injects the tadpole with a toxic saliva that dissolves the tadpoles' insides. Warmer waters caused by climate change means that many tadpoles are now metamorphosing faster and emerging when there is less food available meaning frogs are smaller than before - and more vulnerable to predation.

Froglets

When the froglets emerge they seem so tiny, but already their lungs have developed and ready to venture out of the pond. They will continue to grow for up to four years and, interestingly, individuals often return to the very same pond they were born in. So I'm hoping I'll see these frogs again!