30/05/2016 Newsround

It's bank holiday Monday, you're watching Newsround with me, Ayshah.

Coming up in the next five: The dogs being trained to find koala poo.

And the biggest bouncy castle ever.

First to Formula 1, and Lewis Hamilton is a very happy man.

He's won his first race of the season in Monaco,

beating his team-mate Nico Rosberg and cutting Rosberg's lead

in the championship to just 22 points.

Hamilton says he's sure he can win his third

championship this year.

In the tennis, Andy Murray is through to the quarterfinals

of the French Open.

He beat American player John Isner in straight sets.

Teenager Bethany Shriever from Essex has taken part

in the World BMX Championships in Colombia, South America,

over the weekend.

She represented Great Britain level in the competition

and earned herself a junior women's time trial silver medal.

We've been to meet the 16-year-old to find out more about her

love for BMX bikes.

My name's Bethany Shriever, and I'm a BMX racer for Team GB.

I got involved in the sport of BMX when I was eight years

old through my brother.

One of his friends invited us down the track, and he gave me one

of these and one of these, and I fell in love.

BMX bikes are smaller and harder than most bikes.

It's so they can take everything we put them through.

They're made to be strong, because the track is really

demanding on the bike.

There are lots of jumps on the track, made on a really

hard surface so that you can go really fast.

These bikes are for tracks like this, whereas mountain

bikes are made to go through puddles and mud.

This month I'm heading to Colombia to compete in the BMX

World Championships, representing my country.

There will be loads of people competing from all over the world,

but I'm the only girl competing for the UK in junior level.

If you want to give it a go, get down to your local track.

Anyone can do it.

You don't have to be mad to do it, but it does help!

Have a look at this fossilised skeleton of a massive sea reptile

that lived 165 million years ago.

The ancient bones were discovered at a quarry near Peterborough,

and the creature has been given the nickname Eve.

Next to Australia, where scientists have come up

with a pretty interesting way of tracking down koalas.

The animals are an endangered species across the country,

but now it's hoped koala-tracking dogs might be able to help.

This is Maya, and she's on the hunt for koalas.

The great thing with dogs as they can smell what we can't see.

Koala poo smells very much of eucalyptus, and so they can help

us locate scats very easily.

In many parts of Australia, their numbers are declining

because of habitat destruction, so researchers are trying to figure

out which are the most important areas to keep protected.

You need a lot of stamina, because you have to cover a lot

of ground and look under each tree for scats.

For Maya, that is not a problem, she is playing, and she is 20 times

faster at finding the scats.

And most importantly for conservation, she is 150% more

accurate, so that means she finding scats where humans are not.

For habitat protection, this is critical.

But even the best detectors need to keep their skills up

with a bit of training.

It's very simple, because we don't want to take her into the bush

and for her to start indicating on possum poo or Eastern grey poo.

We want to make sure that Maya knows what koala poo is,

and excludes any other marsupial poo.

If you think about it, dogs don't go to work for a salary.

They go to work and for them it is playing.

You are such a good girl!

And on top of that, for this pup, tracking and playing fetch

rarely feels like work!

Top Gear came back on our telly screens last night.

New presenters Chris Evans and co-host Matt LeBlanc

took to roads in the US, Morocco and in the UK.

It's had mixed reviews on social media, with a lot of people

missing the previous host, Jeremy Clarkson.

We want to know what you think about the new Top Gear.

Go online and let us know.

Finally, fancy having a go on this?

It's claimed to be the world's biggest bouncy castle.

It's being used at a festival in Southampton.

It's taller than the Great Wall of China, and 100 people can use

it at the same time.

That's all from me for now, Newsround's back in half an hour.