In the Season 1 installment "The Sound Of Quacking", the castaways have no food due to a blight. In others, they lament having little to eat but coconuts. Yet, here, they have a case of canned corned beef that they let Gilligan feed to the lion.
The Professor tells the other men that the lion can "smell fear". As a scientist it would have been more accurate for him to say that they sense fear.
Felis leo was changed to Panthera leo in the late 1800s.
Zamba was an African lion, not Nubian as the newscaster says. Nubian lions went extinct in the wild in the 1940s and the last of the captive lions went extinct in the 1960s.
At the end, as the caged lion floats away on the raft, it doesn't particularly resemble the lion appearing throughout the episode. It seems instead to be merely a manipulated lion-sized puppet. This alternative may have been necessary as lions, unlike tigers for example, are not particularly fond of being in or on water.
As Gilligan barricades himself in the Howell's hut not realizing the lion is on the bed, a shadow of another person (possibly the lion handler) can be seen on the floor crossing from right to left.
The radio announcer says that they discovered the lion ate 36 pounds of corned beef. They had no way of knowing the lion ate corned beef.