This video, titled "I Found 5 Stag Beetles! MAX EXCITEMENT!" (まさかのオオクワガタ5匹GET！テンションMAX), was released by "Yamame CHANNEL" (やまめCHANNEL).

The giant stag beetle is one of the largest stag beetles inhabiting Japan.
It lives in the deep woods in tree hollows, as introduced in the video.
They range from 2 to 7 centimeters in length, but larger ones over 9 centimeters have been found in some cases.
Many children are interested in these insects in the wild, and often go out to catch them with their nets and cages.

Keeping stag beetles is also a fun hobby for adults.
In Japan, some people make a living by capturing and selling stag beetles like the one in the video and selling them to collectors.