What happens to a tadpole after about 70 days of life?
At 70 days the tadpole looks like a tiny frog with a very long tail and very short forelimbs. The tadpole will start the process of becoming a frog after becoming full grown tadpole.
Tadpole develops hind limbs first and around 70th day of life forelimbs also appear. Tadpole starts metamorphosis generally after 12th week of life, though there are several species who may remain a tadpole for a couple of years.
Transition from tadpole to frog is a slow and gradual process during which vast changes take place inside the body. Development of legs signals beginning of metamorphosis as appearance of legs transform the tadpole into a less efficient swimmer. Least change takes place in nervous system. The changes could be listed as follows:
- Digestive tract must change to support carnivorous diet of frog. Tadpoles are initially herbivores, later become omnivore. Intestine is very long in tadpole stage, while in adult stomach enlarges but intestinal coil disappears.
Gill breathing habit of tadpole will not be able to support a life on land; a pair of lungs develop for breathing air.
Skin develops a tough outer layer, but to maintain moisture on skin, suitable glands develop.
Skeleton becomes more ossified, mouth widens, jaws get restructured. Skeletal pieces of tail fuse together to form a single bone called urostyle.
Urinigenital system advances to adult type with development of functional gonads.
Tail tissue is gradually reabsorbed by action of lysosomal enzymes.