Researchers have developed a phylogenetic tree that traces evolutionary history of hummingbird. The study, which is quite an astonishing one unveiled that the diversification of hummingbird started 22.4 million years ago.

It diversified into at least 338 species. Researchers from the University of New Mexico have reached at the above mentioned conclusion after analyzing DNA sequence data from 451 hummingbirds from 284 species. Author Christopher Witt said around 42 million years ago, hummingbird had split from its sister group -- the swifts and treeswifts -- in Eurasia.

In South America, the first hummingbird rose and diversification started. During the diversification process, hummingbird has reinvented itself throughout its 22-million-year history.

With passage of time, hummingbird evolved into different groups, affirmed herpetologist Jim McGuire from University of California. To cite an example, topaz hummingbird has diversified into four distinct species and bee hummingbird diversified into 35 different species.

But if diversification rate is compared than bee hummingbird diversified at a rate 15 times faster than that of topazes. As per McGuire, everything about hummingbird is quite extraordinary. "They have this incredible hovering flight, with wing-beat frequencies of 60 times per second, which is nuts. They have the highest metabolic rate for their size of any vertebrate", affirmed McGuire.

It is said that the population of hummingbird species could double in next seven million years. McGuire affirmed that if human would not have been around then hummingbird species would have continued evolving new species over time. There is no denying about the fact that evolution of hummingbirds has been quite tremendous.