The investors are called Dragons on the British television series Dragon's Den.
The term is built into the programme’s title and is the British version’s distinctive name for the people who evaluate entrepreneurs’ proposals. A contestant enters the den, presents a business and asks one or more Dragons for investment in return for an ownership stake.
The Dragons are not a fixed group across the entire history of the show. Investors have joined, left and returned, creating different panels in different series. The original British lineup included Peter Jones, Duncan Bannatyne, Rachel Elnaugh, Simon Woodroffe and Doug Richard, while later series introduced other businesspeople.
International adaptations often use different animal terms. In the United States, the investors are Sharks, which is why viewers sometimes transfer that name to the British programme. Tigers and Lions may sound plausible because of other television titles, but the canonical British term is Dragons.