There are more than 5,000 recorded species of frog (order Anura) in the world, their habitats extending worldwide although they do not occur in the Antarctic nor are they present on many oceanic islands. They are tail-less amphibians; characterized by long hind legs, webbed feet, protruding eyes and a short body. They feed mostly on insects such as crickets, moths, flies and mosquitoes – although larger types of frog have been known to eat small turtles and even other small frogs.
They are capable of jumping incredible distances, with some recorded as leaping over 50 times their body length. This is due to their long hind legs and the way their tarsals, tibia and fibula have fused together to form a singular, strong bone. The bones in the frog’s forelimbs are also merged together in order to absorb the impact of each jump
The Frog Life Cycle
There are four main stages of the frog life cycle: egg, tadpole, metamorphosis and adult. It takes around 70 to 80 days for the frog to complete the egg to egg process.
When sexually active, the adult frogs will breed at a water source such as a stream or a pond. The males will make their signature mating call, a low croak, which will then attract nearby females. Once assembled, the male and female undergo their form of mating called ‘amplexus’, which results in a mass of upto 2000 gelatinous eggs that we call frogspawn. After about a week, these aquatic eggs will hatch and become tadpoles.
Tadpoles have oval bodies and long, flat tails. They are typically herbivores, feeding on algae within their native pond. However, there have been instances of some species being carnivorous at the tadpole stage, feeding on small insects and even other tadpoles. Those who develop legs early may be eaten by other tadpoles in order for them to survive longer.
After reaching the end of the tadpole stage, the frogs transition into adulthood through process of metamorphosis. They develop hind legs, front legs and then lungs. Their intestines change as their diet switches from herbivore to carnivore, followed by a change in their eyes in order to provide the frog with binocular vision. Finally, the frogs lose their tail and reach the adult stage.
Two tadpoles in the metamorphosis process
After reaching full maturity, the adult frogs will either leave the water for dry land, or continue to stay in their aquatic habitat. They will seek out invertebrates such as arthropods and gastropods, sometimes capturing prey with their hands and forcing it into their mouths, sometimes using their sticky tongues to catch fast-moving prey.
Frogs themselves are often preyed upon by birds, snakes, foxes, badgers and fish. Whilst it is not certain how long a frog can live for in the wild, they have been recorded to live for over 40 years in captivity.
There is a rapidly spreading disease called chytridiomycosis that is affecting amphibian populations the world over. Spread by a specific type of fungus (chytrid), the lethal disease spreads to such amphibians as frogs and salamanders through water or moist environments (seen as unusual as this particular form of fungus does not normally affect vertebrates).
“An extinction event on a scale equivalent to that of the dinosaurs”
Chytridiomycosis kills by targeting the skin. Upon contracting the disease, the animal’s skin begins to thicken due to a change in the protein ‘keratin’. As frogs and salamanders often breathe and drink through their skin, this essentially suffocates the animal, causing an abnormal level of electrolyte levels.
Chytridiomycosis is a very high risk to the survival of certain amphibian species, with the International Union for Conservation of Nature calling it “the worst infectious disease ever recorded among vertebrates in terms of the number of species impacted, and its propensity to drive them to extinction.” With such diseases as this coupled with the loss of their habitat, it is important to do what we can in order to prevent such amphibious creatures from dying out.
Frogs in the Garden
Due to these natural and manmade threats, allowing frogs to live in our garden not only brings in a touch of wildlife, but can also help prevent their numbers from diminishing. They need moisture, food, shelter and a place to mate, so making a few changes will make it possible for almost any garden to become a safe frog haven.
A pond should be around 2-3 feet in depth in order for it to be accommodating for frogs. The edges should be shallow in order for them to get in and out with ease, and there should be moist, rough vegetation in close proximity where the frogs can find food and hibernation. It will also be necessary to provide shelter from the summer sun, meaning pond plants such as marigolds and violets will be a welcoming addition. Damp soil around the pond is often required as their skin needs to stay moist in order for them to breathe. Frogs also tend to prefer ponds with no fish.
As highlighted earlier, frogs tend to live on a diet of mainly insects; the same insects who are a nuisance to homeowners and their gardens. Mosquitoes, moths, slugs, snails, flies and even cockroaches can be reduced in numbers by having frogs in the garden and thus potentially saving the job of calling in pest control should the garden/home become infested with insects. Not only does this save money, but it removes the need to use chemicals that could potentially harm grass, plants and flowers.
Although it is necessary to have a pond in the garden to attract frogs, it is actually the surrounding area in which they will spend the majority of their lives - so forming piles of leaves, rocks and other debris will provide a place for frogs to forage and shelter in. Using toxic substances in the garden is not advisable due to the way in which frogs breathe through their skin – such pesticides as slug pellets are no longer necessary anyway due to the fact that slugs are eaten by frogs. In keeping with their desire for the damp, they will often choose to spend their time in the moist, humid atmosphere of the greenhouse.
Although having frogs in the garden can be a pleasure and many will strive to maintain a comfortable environment for them, there are a few things to avoid in order to keep them safe and healthy.
For example, grass should be kept short at all times, as frogs will sometimes shelter in long grass which puts them at risk when mowing or strimming is required. Keeping it a short length will make it easier to spot any foraging frogs before they meet a rather grisly end.
It is not a wise idea to remove a frog its original habitat and place it in a different one, as it will most likely die or migrate. If a garden offers their basic needs then frogs will arrive naturally over time – trying to force them into a new environment will not work.
Finally, if a frog is spotted motionless at the bottom of a pond during winter, then do not attempt to retrieve it. Frogs hibernate during the winter, and some males will bury themselves in mud and lie dormant at the bottom of the pond. Removing the frog will disturb its hibernation process and potentially kill it.
Having frogs in the garden does not require too much maintenance but they are relatively fragile creatures so by following the advice here, the perfect garden environment can be created in which they can prosper.