How the snakes copulate? What are the different reproductory organs in them? Why ANACONDA is ovo-viviparous?
All snakes employ internal reproduction, which means that snakes use sex like mammals to fertilize the eggs. This is accomplished by means of paired, forked hemipenes, which are stored, inverted, in the male's tail. The hemipenes are often grooved, hooked, or spined in order to grip the walls of the female's cloaca. Most snakes lay eggs (unlike mammals) and then abandon them, though there are some exceptions where the snakes will build a nest, such as with the King cobra or pythons.
It has recently been discovered that anacondas are ovoviviparous and the female keeps the egg in her body until it's ready to hatch, thus giving live birth. This has likely happened due to evolutionary advantage (better survival rates).
In the female, the gonads are ovaries positioned in the same area of the body as the testes are in the male; ovaries are attached to oviducts that conduct eggs to the uterus (located between the ovaries and the anal cavity) where, in egg-bearing (oviparous) snakes, the eggs are fertilized by sperm from the anal cavity and then are encased in shells before being expelled.
In live-birthing (viviparous) snakes the eggs are fertilized in and continue to develop in the uterus until, at birth, the young are expelled through the anal cavity. The male produces sperm in testicular gonads, and the sperm is conducted from each teste to the anal cavity, where the male copulatory organ, are positioned.
Anaconda is called ovo-viviparous because they give birth to live young.