Frog Cocoon

In deserts water is scarce. Animals living in deserts have to conserve water and prevent their skin going dry.

Desert frogs of Australia undergo summer sleep or aestivation. During summer, land and air temperatures soar high. Deserts become warmer and are unsuitable for animals to go about hunting for their prey. Most animals hide in shady places and reduce their activity. Some burrow deep into soil to escape sun’s heat.

Australian desert frogs (Hylid frogs) like Cyclorama are generally burrowing frogs. During summer, they remain in their burrows and aestivate. They build cocoons and sleep. The frog cocoon is a protective cover of dead skin cells.

At the beginning of aestivation, the frog settles down in a burrow under desert soil. It holds its limbs close to its body. This is to reduce surface area of the body and prevent evaporation. Then its skin sheds cells which form a thin sheet around the body. Several sheets eventually make the cocoon.

To start with, the cocoon is thin and transparent. As time progresses, more layers are added. The cocoon gradually becomes thicker and opaque, with tightly packed layers of dead epidermal skin cells.

The frog cocoon covers the entire body surface, eyes, mouth, cloacal opening, except nostrils or nasal openings. This allows the frog to breathe air.

During aestivation, the frog becomes totally inactive. Feeding stops. Physiological activities become minimal. Breathing becomes slow, so is the heart beat. The body has reserve fat which is utilized in very small quantities. Water conservation is at its high.

Aestivation may last two to three months. Despite such long period of inactivity, the frog does not lose its muscle mass. Its special mechanism prevents muscle wasting. When monsoon sets in, the frog emerges from its cocoon, resumes its activity, leaping and catching prey, its usual style.