0:00:05 > 0:00:08It's bank holiday Monday, you're watching Newsround with me, Ayshah.
0:00:08 > 0:00:11Coming up in the next five: The dogs being trained to find koala poo.
0:00:11 > 0:00:15And the biggest bouncy castle ever.
0:00:25 > 0:00:29First to Formula 1, and Lewis Hamilton is a very happy man.
0:00:29 > 0:00:31He's won his first race of the season in Monaco,
0:00:31 > 0:00:35beating his team-mate Nico Rosberg and cutting Rosberg's lead
0:00:35 > 0:00:37in the championship to just 22 points.
0:00:37 > 0:00:39Hamilton says he's sure he can win his third
0:00:39 > 0:00:40championship this year.
0:00:40 > 0:00:42In the tennis, Andy Murray is through to the quarterfinals
0:00:42 > 0:00:44of the French Open.
0:00:44 > 0:00:47He beat American player John Isner in straight sets.
0:00:49 > 0:00:52Teenager Bethany Shriever from Essex has taken part
0:00:52 > 0:00:54in the World BMX Championships in Colombia, South America,
0:00:54 > 0:01:00over the weekend.
0:01:00 > 0:01:02She represented Great Britain level in the competition
0:01:02 > 0:01:04and earned herself a junior women's time trial silver medal.
0:01:04 > 0:01:07We've been to meet the 16-year-old to find out more about her
0:01:07 > 0:01:10love for BMX bikes.
0:01:12 > 0:01:16My name's Bethany Shriever, and I'm a BMX racer for Team GB.
0:01:18 > 0:01:21I got involved in the sport of BMX when I was eight years
0:01:21 > 0:01:25old through my brother.
0:01:25 > 0:01:28One of his friends invited us down the track, and he gave me one
0:01:28 > 0:01:32of these and one of these, and I fell in love.
0:01:33 > 0:01:36BMX bikes are smaller and harder than most bikes.
0:01:36 > 0:01:42It's so they can take everything we put them through.
0:01:42 > 0:01:45They're made to be strong, because the track is really
0:01:45 > 0:01:51demanding on the bike.
0:01:51 > 0:01:54There are lots of jumps on the track, made on a really
0:01:54 > 0:01:56hard surface so that you can go really fast.
0:01:56 > 0:01:58These bikes are for tracks like this, whereas mountain
0:01:58 > 0:02:01bikes are made to go through puddles and mud.
0:02:01 > 0:02:03This month I'm heading to Colombia to compete in the BMX
0:02:03 > 0:02:04World Championships, representing my country.
0:02:04 > 0:02:07There will be loads of people competing from all over the world,
0:02:07 > 0:02:10but I'm the only girl competing for the UK in junior level.
0:02:10 > 0:02:14If you want to give it a go, get down to your local track.
0:02:14 > 0:02:15Anyone can do it.
0:02:15 > 0:02:18You don't have to be mad to do it, but it does help!
0:02:21 > 0:02:24Have a look at this fossilised skeleton of a massive sea reptile
0:02:24 > 0:02:28that lived 165 million years ago.
0:02:28 > 0:02:31The ancient bones were discovered at a quarry near Peterborough,
0:02:31 > 0:02:34and the creature has been given the nickname Eve.
0:02:39 > 0:02:41Next to Australia, where scientists have come up
0:02:41 > 0:02:43with a pretty interesting way of tracking down koalas.
0:02:43 > 0:02:45The animals are an endangered species across the country,
0:02:45 > 0:02:50but now it's hoped koala-tracking dogs might be able to help.
0:02:53 > 0:02:57This is Maya, and she's on the hunt for koalas.
0:02:59 > 0:03:03The great thing with dogs as they can smell what we can't see.
0:03:03 > 0:03:06Koala poo smells very much of eucalyptus, and so they can help
0:03:06 > 0:03:10us locate scats very easily.
0:03:10 > 0:03:13In many parts of Australia, their numbers are declining
0:03:13 > 0:03:16because of habitat destruction, so researchers are trying to figure
0:03:16 > 0:03:21out which are the most important areas to keep protected.
0:03:21 > 0:03:25You need a lot of stamina, because you have to cover a lot
0:03:25 > 0:03:28of ground and look under each tree for scats.
0:03:28 > 0:03:32For Maya, that is not a problem, she is playing, and she is 20 times
0:03:32 > 0:03:36faster at finding the scats.
0:03:36 > 0:03:39And most importantly for conservation, she is 150% more
0:03:39 > 0:03:42accurate, so that means she finding scats where humans are not.
0:03:42 > 0:03:43For habitat protection, this is critical.
0:03:43 > 0:03:46But even the best detectors need to keep their skills up
0:03:46 > 0:03:52with a bit of training.
0:03:52 > 0:04:00It's very simple, because we don't want to take her into the bush
0:04:00 > 0:04:03and for her to start indicating on possum poo or Eastern grey poo.
0:04:03 > 0:04:08We want to make sure that Maya knows what koala poo is,
0:04:08 > 0:04:10and excludes any other marsupial poo.
0:04:10 > 0:04:13If you think about it, dogs don't go to work for a salary.
0:04:13 > 0:04:15They go to work and for them it is playing.
0:04:15 > 0:04:17You are such a good girl!
0:04:17 > 0:04:19And on top of that, for this pup, tracking and playing fetch
0:04:25 > 0:04:27rarely feels like work!
0:04:27 > 0:04:33Top Gear came back on our telly screens last night.
0:04:33 > 0:04:35New presenters Chris Evans and co-host Matt LeBlanc
0:04:35 > 0:04:37took to roads in the US, Morocco and in the UK.
0:04:37 > 0:04:40It's had mixed reviews on social media, with a lot of people
0:04:40 > 0:04:42missing the previous host, Jeremy Clarkson.
0:04:42 > 0:04:44We want to know what you think about the new Top Gear.
0:04:44 > 0:04:46Go online and let us know.
0:04:46 > 0:04:48Finally, fancy having a go on this?
0:04:48 > 0:04:50It's claimed to be the world's biggest bouncy castle.
0:04:50 > 0:04:52It's being used at a festival in Southampton.
0:04:52 > 0:04:55It's taller than the Great Wall of China, and 100 people can use
0:04:55 > 0:04:56it at the same time.
0:04:56 > 0:04:58That's all from me for now, Newsround's back in half an hour.