Here is the list of different species of anaconda by size:
1. Dark spotted anaconda(13.12 feet).
2. Eunectes Stirtoni (9.87 feet).
3. Bolivian anaconda(13.12 feet)
4. Yellow anaconda (15.10 feet).
5. Green anaconda(28.15 feet).
Anaconda is the biggest snake in the world. It can easily eat a small cow and even a human.