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American Bullfrogs are mainly found in North America and Canada. They are also known as “Bullfrogs”. The members of this species are aquatic (residents of water). They are regarded as one of the most interesting frog species in the world. Read this article to know more about their appearance, distribution, habits and needs.
These frogs are of a brownish-green color with the backs marked with dark spots. The bellies are of a white or yellowish color. Sometimes black spots or vein like patterns can be noticed. They also have a pair of webbed hind legs.
The American Bullfrogs have a large, stocky appearance and are regarded as the largest among all North American frogs. They can grow anywhere from 10 to 14 inches in size. The length of the body is usually somewhere between 3.5 – 6 inches with the legs adding an extra 7- 10 inches. They can weigh up to 750 gms (1.5 pounds). The tadpoles of this species may grow 6.75 inches in length.
Male and Female Identification
There are a few differences in the appearance of the male and the female frogs. These help in identifying male frogs from females. Here is information on some of these differences:
- The male Bullfrogs are usually larger in size than the female ones.
- The eardrums of the males are even larger than their eyes. The female frogs have eardrums that are as large as their eyes.
- The females have smoother skin than the males, who have textured skin.
They can be found in the central and eastern regions of America. The distribution range of this species extends approximately from Nova Scotia in the north to Texas (Rio Grande River) and Central Florida in south and Colorado and New Mexico in the West. They can also be found in areas as far as Wisconsin and Rockies. It is not easy to determine the exact range of these animals. The members of this species were introduced in areas outside their natural habitat by humans in the 1920s, to use them as food. From that time, the Bullfrogs have established their habitation in areas like:
- Western America
- British Columbia
They were introduced in other far off places and even other continents like:
- South America
- Caribbean Islands
Habitation and Environmental Needs
These creatures are aquatic and do not like to live in over populated areas.
- Slow-moving streams
- Slow river backwaters
- Cattle tanks
- Irrigation canals
- Slow creek
They like to live in open, warm and sunny waters where there is enough vegetation for them to hide from any apparent danger. They need permanent ponds or other water lands as they are completely aquatic creatures and their tadpoles take more than one year to complete their transformation process.
They can occasionally be found in:
- Desert oases
The breeding season starts in May and continues through October. The males attain adulthood somewhere between 2 and 4 years, while the females become reproductively mature when they are 3 or 4 years old.
The males call and try to attract the females during the breeding season. They become very protective of their own territory during this time. Once the mate is selected, the male and the female frogs move to the breeding spot. The reproduction takes place in water (aquatic).
Females of this species can lay as many as 20,000 eggs at a time. The eggs float in water, bound together by a jelly like substance. The fertilization of the eggs is external. After 3 to 5 days, the eggs sink underwater to hatch.
The transformation of the tadpoles starts after a few months. The transformation process takes more than a year to complete. Sometimes, a tadpole even takes three years to complete this process.
Read the following pieces of information to know about some common behaviors of this species:
- These animals apply the Positive Air Breathing process for respiration. It means they close their nasal cavities and mouths after inhaling the air through the nostrils. As a result, the air is forced to go into their lungs. At the time of exhalation, the wall of the body squeezes itself to force the air out.
- The male frogs may chase or attack other frogs in order to protect their territory. They might even fight or wrestle between themselves for this reason.
- These animals have a habit of shedding their skin. They open their mouth wide and pull themselves out of the skin in order to shed it. They use their legs to pull the skin over their head and then eat it.
The average lifespan of these frogs is 7 to 10 years. However, a particular member of this species has been known to live for 16 years.
These creatures are known to prey on any other animal they can conquer and swallow, including other Bullfrogs. Their diet consists of:
- Small mammals
- Small birds
The tadpoles usually eat:
- Some invertebrates
- Aquatic plant matter
They pose a primary threat to some endangered species of frogs and reptiles like California Tiger Salamander and California Red Legged Frog. Due to this reason, the state of California is trying to control the population of Bullfrogs in their environment.
Some animals that prey on these creatures are:
- Large snakes
- Large fish
Humans are also counted in this list of predators as they use these animals as a source of food. Their hind legs and backs are used for consumption.
These frogs have a deep and resonant voice and their call resembles that of a cow. This is why they are called the “Bullfrogs”. The call of the male members of this species sounds like a low and rumbling “jug- o- rum”. Their loud chorus can be heard from a great distance especially during nighttime. Sometimes, they may also call during the day.
Their adaptations make them a very powerful organism in their environment. Read on to learn about how they have adapted to survive in the wild:
- Their grey green color makes it hard for their predators to find and catch them.
- Their hind legs can grow as long as somewhere between 7 and 10 inches. The length of their legs helps them jump to a great height.
- They can jump and catch their pray from a very long distance with the help of their long hind legs.
- Their tongues are very strong and it helps them to overpower the prey.
- They also have sharp teeth. These teeth are situated on the roof of the mouth.
- Their well-developed eyes can see in all directions. This helps them to build and protect their territory, find a mate and also to stalk or hunt a prey.
- Their skin has adapted in a unique way. Like other aquatic animals, they can breathe through the skin. But they also have many glands on the skin surface. These are called the “parotid glands”. Whenever a frog feels any threat, it secretes a toxic substance through these glands on its skin surface. This toxin is strong enough to kill an animal (as big as a dog), if they try to eat the frog.
Here are some interesting facts about these creatures:
- Bullfrogs can jump 9 times their body weight at a time with help of their strong hind legs. They can cover any area between 3- 6 ft in a single jump.
- They have an interesting method of swallowing their food. They close their eyes while swallowing. Then the eyes help them in the process by sinking down into the head and helping them to push the food down the throat.
- A band of these frogs is known as an “Army”.
These frogs are quite popular and make good pets. They are quite easy to take care of. Following are some information about keeping and feeding them:
- They should be kept in a large tank (minimum 100 gallon, but the larger the better).
- Two thirds of the tank should contain water, with the rest filled with soil.
- The frog should be able to get in the water and out of it whenever it wants. Putting live plants in the water can be good for your pet.
- They have a huge appetite. So, those desiring to domesticate them will have to provide them with a range of foods. They may eat large and small insects, earthworms and other bugs. You may occasionally feed them with small frogs and mice.
- Never feed it with wild insects and bugs. They may carry some infections that might be harmful for your pet.
- Provide your pet with a vitamin supplement once every week or fortnight.
- It is not advisable to keep more than one frog in a single tank as they do not like company. It might even eat the other frog if kept together.
Are American Bullfrogs Endangered?
The members of this species are included in the “Least Concern” category by the International Union for Conservation of Nature and Natural Resources (IUCN). This indicates that this species is not under any existential threat.
Are you interested to find out how these creatures look like? Here are some American Bullfrog photos for you to get an idea about the appearance of these animals.
American Bullfrogs are an exceedingly interesting species of frogs and a popular choice for pets. But, over population of these creatures may pose a threat to other threatened and endangered animals.