Amazing Facts About the Frogs
Over 5,000 different frog species live in temperate and tropical habitats worldwide, but all share the same basic shape, with large hind legs that are excellent for jumping, swimming and digging.
What do Frogs look like?
Unlike other amphibians, adult frogs have no tails. Instead, they have large hind legs, wide mouths, protruding eyes and damp skin through which they can absorb oxygen.
Frogs range in colour from the dull brown European common frog to the bright red strawberry poison frog. Tropical rainforests have the greatest diversity of species, with some relying on muted camouflage colouring to hide from predators, while others are brightly coloured to advertise they are poisonous or simply just taste horrible!
What is the difference between Frogs and Toads?
Depending on where in the world you live, the terms frogs and toads are used differently. Generally, however, frogs are much faster, have smooth skin and spend most of their time in the water. Toads are slower, have rough skin and often burrow into the ground.
Where do Frogs live?
Amphibians are cold-blooded. They have permeable skin, so they must find damp places to live to prevent them from drying out. As such, frogs thrive in freshwater habitats. Some spend their whole lives in water, while others only visit water to breed. Many species in the humid rainforests live high in the trees, safely away from ground-dwelling predators. Frogs inhabit every continent except Antarctica.
What do Frogs eat?
Frog larvae, known as tadpoles, feed mostly on plant material, but adult frogs are carnivores. Depending on their size, frogs eat everything from insects and invertebrates to small mammals and other frogs! Frogs are ambush predators. They lie in wait to catch their prey, often with a spectacular jump!
What sounds do Frogs make?
Frogs make a range of sounds, from the high-pitched squeaks of the squeaker frogs to the more traditional croaks of bullfrogs. They make noise for various reasons, such as to defend their territory or to warn other frogs when danger is near. Most often, though, frogs make noise to attract a mate – the choruses of frogs gathering in huge numbers to breed can be deafening! Males make noise to attract females, filling their vocal sacs with air and expelling it to make their calls. The loudest frog species in the world is the coqui, whose call has two parts – a low-frequency ‘co’ warning rival males to keep their distance and a high-pitched ‘qui’ to attract females.
When do Frogs breed?
Frog species in tropical climates can reproduce several times at any point in the year, while those in high-latitude countries typically breed in early spring. Species like the common frog in the UK usually return to the pond where they themselves were spawned to breed. Male frogs often attract females using sound, but some species, such as the Panamanian golden frog, use visual displays to impress females. This is one of the most endangered frog species. It is critically endangered on the IUCN Red List of Endangered Species and may be extinct in the wild.
Fertilisation
In the majority of species, fertilisation of eggs is external. The male hugs the female tightly in a position called amplexus and fertilises her eggs as she releases them. Female Frogs can produce anything from one to 50,000 eggs, depending on the species. For some species, this is the extent of parental care, with just a few eggs surviving to adulthood. Other species produce fewer eggs but invest more time caring for them by defending them from predators or feeding the tadpoles unfertilised eggs. Some species carry eggs and tadpoles from one location to another to escape predators or reach a more advantageous environment. Perhaps one of the most interesting is Darwin’s frog – the males ingest the eggs and keep them safe in their vocal sacs. Once the eggs hatch, the tadpoles stay in the vocal sac and feed on egg yolks. They hop out as fully-formed frogs!
Metamorphosis
The process of changing from a tadpole to a frog is called metamorphosis. Tadpoles develop inside the eggs over a few weeks (depending on the species) and then hatch straight into the water. Tadpoles look like little commas with large heads and long tails. Over the next few months, tadpoles slowly develop legs and absorb their tail back into their bodies to save wasting nutrients. Their gills are replaced with air-breathing lungs. However, in some frog species, like the robber frogs of the Americas, eggs develop directly into small adults without a tadpole stage.
What are the threats to Frogs?
Frogs have many natural predators, including birds such as herons, reptiles like snakes and alligators, mammals like otters, large fish and other frogs. In some areas, humans have introduced non-native frog species. These compete with native species and can have a huge impact on populations.
Some of the biggest threats to frogs include habitat loss and the pollution of waterways with chemicals and plastic waste. Frogs have very specific needs and have to be close to water sources. If they lose their habitat or it becomes fragmented because of new developments, they can struggle to find a new home. And many die on roads as they travel between freshwater sources.
Frogs are vulnerable to climate change and unpredictable weather. For example, when they lay their frogspawn too early in unusually mild weather, sudden frosts and snow can kill the whole brood. This is of particular concern for frogs in colder climates as they only spawn once a year, so losing the frogspawn to frost can devastate a population.
Warming temperatures also increase the survival and spread of pathogenic fungi. Two species of fungi are responsible for a disease called chytridiomycosis, which is thought to have led to declines in over 500 frog species. The fungus prevents frogs from taking in oxygen and water through their skin. Chytridiomycosis is likely spread by fungal spores that are transported worldwide, for example, by people on their boots and equipment. They may also come from other frogs, particularly those from the pet trade.
How can you help Frogs?
One of the simplest ways to help frogs (and other species) in your own garden is to create a pond – the bigger, the better! Larger ponds are less likely to dry out in summer, but depth is the most important aspect to get right. To be suitable for frogs, ponds must be at least 50 cm deep so they can hibernate at the bottom over the winter. It is also important to have a shallow edge for easy access and native vegetation. It may take a while for frogs to find your new pond, so if you are trying to attract them, be patient, and they will come.
Another thing you can do to help frogs is to respect their home. If visiting nature reserves, follow all instructions, particularly regarding protective measures such as washing your footwear before entering. This is important to limit the spread of pathogens between water sources.
Finally, many conservation groups exist worldwide to help frogs, including Save the Frogs and the National Wildlife Federation. Conservation sometimes involves keeping frogs in captivity, safe from predators and disease. Once it is safe to do so, conservationists can then release the frogs into their natural habitat. Closer to home, volunteer groups can help frogs by creating bridges or tunnels across roads to allow safe passage for frogs – why not see if there are local groups in your area?
Page updated April 2023 by OneKind volunteer Ami Patrick.
