Joyprakash Bezbaruah, 50, died in hospital after the attack, which occurred in front of his wife, son and dozens of bystanders on Wednesday afternoon.
The family had approached the cage containing two Royal Bengal tigers, one male and one female. The man climbed over the first safety barrier surrounding the cage, ignoring the warnings of zoo officials, and put his hand between the bars to take a picture with his mobile phone.
The male tiger leapt on the visitor ripping is arm from the shoulder, and the female joined in the attack. Vets and zookeepers then pushed the animals away with sticks.
Guwahati zoo has seen similar tiger attacks in the past. Earlier two men jumped into the tigers' cage in an apparent suicide. In another incident, a girl was rescued after entering a tigers' cage.
