In the video, the lion can be seen refusing to let go of the man's finger. An eyewitness stated that the incident occurred when the zookeeper was showing off in front of the crowd at the Jamaica Zoo

A zookeeper's finger was ripped off by a lion after he poked his hand through the fence of its cage. The video, which has gone viral, captures the horrifying moment in which the man is seen trying to pull his hand away from the cage, while the lion refuses to let go.

The clip begins with the man teasing and playing with the lion as it is a cat. He ignores the animal's snarling and continues to trouble it. Seconds later, the animal clamps its powerful jaws around the man's finger. As the man struggles to break free, the lion keeps its mouth shut tight around his finger.

Reference https://www.firstpost.com/world/watch-zookeeper-teases-lion-animal-bites-off-his-finger-10709731.html