The American adaptation of the television format known in Britain as Dragon's Den is Shark Tank.
Shark Tank premiered in the United States as an adaptation of the international entrepreneur-investor format. Its central idea is the same: business owners present their companies to wealthy investors and seek money in exchange for equity or another negotiated arrangement.
The principal naming difference is the animal metaphor. British investors are called dragons, while the American programme calls its investors sharks. The change reflects local branding rather than a different underlying concept.
The two programmes have separate presenters, investors and production histories, so Shark Tank is not simply an American season of the British series. They are related adaptations of a format that began in Japan. Comparing the titles is useful because several countries use different names for versions with essentially the same pitch-and-investment structure.