It covers 965 populations of 365 species, representing 35 percent of all known vertebrate species found in the Arctic.

They have no direct toxic effects on vertebrates.

China has the world's largest number of terrestial vertebrates, with a total of 1,800 species, which accounts for approximately one-tenth of the same species of vertebrates in the world.

But how do they - and the other 70 species of vertebrates that propagate this way - do it without the genetic monotony and disease vulnerability that often results from asexual reproduction?

And because of their size and few predators, whales and other big marine vertebrates can efficiently export carbon from the surface waters to the deep sea.