Do Frog Eggs Have Shells? (Why They Lay Egg In Water?)

This article will explain Do Frog Eggs Have Shells? Frog eggs have shells like jelly material. Over 7,000 different species of frogs can be found worldwide.

The majority of these species reproduce by laying eggs, typically in freshwater bodies that are shallow, stationary, or moving slowly and are free of fish predators.

To protect their young and keep them from drying out, frogs lay their eggs in water. Eggs laid by frogs do not have a hard outer shell like those laid by reptiles or birds.

Rather, a thick jelly layer is placed on top of each egg. The jelly binds the eggs together, shielding the embryos from the environment as they develop.

Frog egg masses are closely packed and highly dense when first laid. The jelly covering the eggs gradually swells as a result of water absorption.

The jelly needs a moisture supply to shield the growing embryos successfully. Lack of moisture might cause the eggs to dry, harming the growing embryos.

Do Frog Eggs Have Shells?

Frog eggs don’t have a shell, so they need some liquid to keep them from drying out before they hatch. Some frogs have found other ways to keep their eggs moist than just putting them in the water.

Reasons Why Many Frog Species Lay Their Eggs In Water?

As was previously said, most frog species prefer shallow, stationary, or slow-moving freshwater bodies free of fish predators.

This could occur in ephemeral rain puddles, highway ditches, deep tire tracks, seasonal pools, river margins, lake edges, river backwaters, bogs, marshes, swamps, ponds, reservoirs, and woodland ponds.

Occasionally, some frog species, including the American green tree frog (Hyla cinerea), will lay their eggs in water containing fish.

Other frog species, including the waterfall frog (Ranoidea nannotis) and the coastal-tailed frog (Ascaphus truei), lay their eggs in swiftly moving streams and cling to them beneath big boulders. Many frog species lay their eggs in water for the following reasons:

Water Cushions The Eggs And Protects The Developing Embryos

Eggs from many reptiles and birds have tough exterior shells. The egg’s shell shields and supports the fragile inside tissues and guards against desiccation.

On the other hand, frog eggs lack a protective shell. Instead, each egg has a substantial layer of protective coating. Instead of a hard protective shell, frog eggs are encased in jelly. 

The eggs can float close to the water’s surface, where it is warmer, and there is more oxygen, thanks to this jelly. Due to its sticky nature and propensity to gather a layer of pond debris, the jelly holds the eggs together and shields the developing embryos from the elements.

Additionally, it performs as a shock absorber to shield the egg from damage caused by water movement. Water provides the necessary cushioning since frog eggs are fragile; most need it to prevent damage to the growing embryos.

Water Enables The Jelly Of The Eggs To Expand

Frog egg masses are initially laid in very close proximity and are covered in unique secretions produced by a gland on the frog’s body. A mass of recently laid wood frog eggs. The eggs are quite tightly packed and do not yet have a noticeable jelly coating, as can be seen.

The egg mass becomes looser as these secretions mix with water to form a jelly-like coating surrounding each egg. The eggs’ jelly coating can expand when laid in water, effectively protecting the developing embryos.

Water Prevents Frog Eggs From Drying Out

For frog eggs to mature correctly, they need moisture. The eggs’ jelly keeps them from drying out, but it must be kept near a source of moisture. This moisture is provided by water.

Since most frogs clamp their eggs together, some may be exposed to the water’s surface and dry out, killing the embryos as they develop. The eggs will not dry out since they will be kept moist in touch with the water. S

ome frog species construct foam nests in the water where they lay their eggs, like the Fletcher’s frog (Platyplectrum fletcheri) of eastern Australia. The foam nesting acts as a barrier for the eggs, protecting them from the weather and some predators’ eyesight.

Most importantly, it offers reliable desiccation prevention. When the nest’s outside mucus dries to produce a hard outer cast, reflecting sunlight and capturing moisture, the nest’s defensive qualities are further improved.

The defense is so strong that even if the water in which the eggs were set dries up, Fletcher’s frog eggs can survive and develop for several days.

Water Shields The Eggs From Harmful Temperatures

Numerous frogs have lengthy breeding seasons; depending on the season in which they are laid, their eggs may be exposed to various temperatures.

The environment’s temperature must remain within a specified range for frog embryos to develop healthily. Since their development rate slows when temperatures drop outside their optimum range, eggs will take longer to hatch.

Additionally, the embryos may perish if the temperatures fall too low. On the other hand, if temperatures exceed the desired range, growing embryos may overheat and suffer a high risk of death.

Late frosts or an early warm period followed by cold temperatures can kill developing eggs and cause the spawn to die from frost damage (particularly any that are exposed above the water). Laying eggs in water offers them some degree of defense against the elements.

Water Protects The Eggs From Some Predators On Land

Most frog species don’t care for their eggs in any way. The males and the females will leave the pond after mating, leaving the eggs behind. This implies that the eggs are vulnerable to numerous predators because they are left to fend for themselves.

When eggs are laid in water, some predators that only hunt on land are kept at bay. But many bodies of water, including rivers and lakes, also include a lot of predators, like fish.

Because of this, many frog species will only lay their eggs in freshwater bodies devoid of fish. This might occur in transient rain puddles, ponds in the woods, or other bodies of water.

Conclusion

Frog eggs don’t have shells, they have jelly-like material around the egg. To prevent the egg’s contents from drying out is one of the key goals of the shell.

Frogs don’t need a shell for their eggs because they lay them in water. Thus, there is no risk of that. Water must be present for the eggs to be laid, and as soon as water contacts the eggs, they absorb it and enlarge.

Some species, like tree frogs, can survive with very little water. A small collection of drips on a leaf may be it. Although mating in frogs may appear identical to other animals, the female releases eggs from her cloaca while the male simultaneously releases sperm from his cloaca.

In reality, the eggs are fertilized outside of the female’s body. The egg’s strong shell would inhibit fertilization.

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