Alex Ritson

It's the only tiger subspecies that was able to show a positive population trajectory throughout the 19th century.

So going from a low of just a couple dozen in Russia in about 1940 to a total population of about 500, 550 today.

And the story in China is even more remarkable.

They were written off as basically extinct.

In about the year 2000, some surveys had been done

that found only about a dozen left.

And now, today, there's thought to be between 70 and 80, so it's a really remarkable turnaround for these cats.

And what is it about them that so draws you to them, to concentrate on them for such a large amount of your professional life?

Well, tigers are considered, what we call in conservation biology, an umbrella species.

So it's a species that garners attention, and if you're able to protect that one species,

It protects many other things.

It's sort of like an umbrella protects a body from the rain.

Again, because these animals have such large territories, I mentioned 400 square kilometers for a female, males require up to 1,400 square kilometers.

If you're protecting enough habitat for a functional population of Amur tigers, that means everything else in the whole landscape is essentially also being protected.

So it's a really good species to focus on.

Conservationist Jonathan Slatt.

A controversial tennis match is taking place later in Dubai.

On one side of the net, Irina Sabalenka, the women's world number one and current US Open champion.

On the other, Australian Nick Kyrgios, a former Wimbledon finalist who's now ranked more than 650th in the world.

The one-off exhibition match has drawn criticism from some for belittling the women's game by putting the leading female tennis player of the day against a male player well past his prime.