by Adam Frost
‘You’ve seen a photo of a hippo with its mouth open?’ Dr Sharp asked.
Tom and Sophie nodded.
‘If it chooses to clamp it shut, it can kill a lion with a single bite.’
Sophie bit her bottom lip and looked at Tom, who had a slightly worried expression on his face.
‘And you’re going to put your head in its mouth?’ Tom asked.
‘Hang on,’ Dr Sharp said. ‘First of all, we’re not lions or a crocodiles. And secondly, she’s a pygmy hippo, so everything’s a lot smaller, including her teeth.’
Tom and Sophie felt slightly calmer until they turned a corner and saw Harriet, standing by the edge of her pool, with her mouth wide open and her large canine teeth shining in the sun.
‘Whoa,’ they both said, taking two steps backwards.
Mr Nightingale appeared and looked confused. ‘No need to worry, kids,’ he said. ‘I’m just getting her ready for Dr Sharp. We’ve trained her to open her mouth.’ He held up the whistle around his neck.
Tom and Sophie relaxed slightly.
Harriet was about one metre tall and almost two metres long, with a slighty rounder head than a full-sized hippo.
Mr Nightingale pointed to a red mark on Harriet’s top lip. He said, ‘I first noticed this about a month ago and it’s got steadily worse.
I don’t think it’s a cut or a sore, so I’m a bit at a loss as to what’s causing it.’
Dr Sharp and Violet poked gently around in Harriet’s mouth. Harriet’s eyes shifted uneasily but she kept her mouth open.
‘She’s very patient, isn’t she?’ Sophie said.
‘She’s a patient patient,’ said Tom with a grin. ‘Geddit?’
‘Hilarious,’ said Sophie.
Dr Sharp finished examining Harriet and turned to face everyone. ‘Her teeth are to blame for her sore lip. See her lower right canine, here?’ He pointed at one of the long sharp teeth in the hippo’s bottom jaw. ‘It’s got slightly wonky and started to dig into her lip every time she closes her mouth.’
Mr Nightingale nodded. ‘So what do we do?’ he asked.
Violet bent down and pulled a giant nail file out of her bag.
‘Wow, is any of your equipment normal-sized?’ Tom asked.
‘Every morning you need to file the side of her tooth down with this. To make it straighter. Starting this morning.’
‘Won’t that hurt her?’ said Sophie.
Violet shook her head. ‘There are no nerves in the outer ivory of her teeth. It will tickle her slightly, but it won’t hurt.’
‘I’m great at filing!’ Tom said. ‘I helped Dad make a coffee table for our houseboat. I had to make all the edges smooth. So if you need a hand . . .’
‘I think your Dad should probably go first,’ Violet said. ‘It’s pretty tough going. Remember, her teeth are among the strongest in the world.’
‘OK,’ said Tom begrudgingly.
Mr Nightingale started to file down the side of Harriet’s wonky tooth. When he’d removed some of the ivory, he handed the file back to Violet.
‘Can I have a go now?’ asked Tom.
‘And me too!’ said Sophie.
‘Well, I suppose there’s no harm in you having a try,’ said Violet.
‘Me first!’ said Tom, and Sophie rolled her eyes, as Violet passed Tom the file.
The file was so heavy and the tooth so tough that they didn’t make much progress.
‘Never mind,’ Mrs Nightingale said. ‘It’s all good exercise.’
‘Her tooth’s as hard as rock,’ Sophie said, wiping her brow and handing the file back to Violet.
‘Harder,’ said Tom. ‘Can anything else open its mouth that wide?’ he asked, staring at Harriet, whose mouth was still open.
‘Hardly anything,’ said Mrs Nightingale. ‘A hippo can open its mouth 150 degrees. That’s almost half a circle.’
Tom opened his mouth as wide as he could.
‘Shall we file your teeth now, Tom?’ Violet asked with a smile.
‘Let’s do it!’ exclaimed Sophie. ‘Pass me the file, Violet!’
Tom quickly closed his mouth again.
Chapter 3
That afternoon, after Dr Sharp and Violet had left, Tom and Sophie talked about nothing but teeth for at least half an hour. They went to the zoo shop and stood in the aisles for about fifteen minutes, flicking through the books to find any mentions of teeth.
‘This one says that dolphins have more teeth than any other animal,’ said Tom. ‘They’ve got, like, two hundred!’
‘It says in this book says that sharks lose and regrow their teeth every couple of weeks,’ said Sophie, ‘so they grow up to thirty thousand teeth in the course of a lifetime.’
‘Thirty thousand teeth!’ said Tom. ‘Imagine how much money you’d get from the tooth fairy!’
Sophie snapped her book shut. ‘We should help Dr Sharp.’
‘What do you mean?’ Tom asked.
‘We should keep an eye on the zoo animals’ teeth,’ said Sophie. ‘Monitor them every week. Check they’re eating properly. Look out for any sore jaws.’
‘OK,’ said Tom, ‘but how?’
‘We’ll take photos,’ said Sophie. ‘We’ll talk to zookeepers. We’ll analyse animal droppings. We’ll video them eating their meals. We’ll be Dental Detectives!’
‘Tooth Sleuths,’ added Tom.
‘Youth Tooth Sleuths,’ said Sophie.
They spent the rest of the afternoon going from one enclosure to the next, working out whether each animal had teeth and, if so, whether they needed to be monitored.
Sophie had a map of the zoo and placed a blue cross next to animals they knew didn’t have teeth and a red circle around those that belonged on their Patients’ Register.
They paused in front of the giant Galapagos tortoises. One of the tortoises had a bunch of leaves sticking out of its mouth.
‘They must have teeth, right?’ Tom asked.
‘No, I read about this earlier,’ said Sophie. ‘No tortoises have teeth.’
‘But look, it’s chewing,’ said Tom.
‘It breaks down its food with its strong beak and its tough jaws,’ Sophie said. ‘No teeth are involved.’
‘So they’re a bit like Grandad then?’ Tom said with a grin.
Sophie grinned back and put a blue cross on the map next to the giant tortoises.
A few minutes later, they were staring at the Sumatran tigers.
‘Now, they definitely have teeth,’ said Tom.
‘Yeah, I really hope they don’t have any dental problems,’ said Sophie. ‘I wouldn’t want to give one of them a filling.’
One of the tigers came towards them and yawned, showing off its huge canines and razor-sharp back teeth. It was by far the smaller of the two tigers so Tom and Sophie knew it was Lizzie, the female.
‘Wow, look at Liz,’ said Tom. ‘That book was right – all her teeth are sharp, even the ones at the back.’
‘Look at how big her canines are,’ Sophie said. ‘They must be seven centimetres at least. I remember reading that a tiger’s canines are really sensitive to pressure. That lets them work out exactly where to bite a deer’s neck.’
Tom shuddered. ‘Or a person’s neck,’ he said.
‘Tigers don’t eat people,’ said Sophie, rolling her eyes. ‘I mean they rarely eat people.’
At that moment Tom spotted a pigeon strutting up and down beside the tigers’ pool. ‘Look, Soph,’ he said, ‘how did that get inside? It wasn’t there a minute ago.’
‘It must have squeezed in through the top of the enclosure somehow,’ said Sophie, looking up.
‘It’s dead meat,’ said Tom.
The male tiger had emerged from a cluster of shrubs, sniffing the air.
‘Looks like Ziggy has woken up,’ said Sophie.
‘Yes, for his breakfast,’ said Tom.
The pigeon was bending forward and pecking at the surface of the pool.
The male tiger crouched down, lowering
its body so its belly was nearly touching the ground. Then it took one step forward, moving slowly towards the bird.
‘Wow, he moves just like Mindy and Max,’ said Tom.
‘I really don’t want to see this,’ said Sophie, putting her hands in front of her eyes but then peeking out.
Ziggy was staring fixedly at the pigeon. His feet made no sound as he moved across the stone floor of the enclosure.
The pigeon was strutting backwards and forwards again.
The tiger’s steps were faster now, but still silent.
Tom and Sophie were on the verge of calling out. Shouldn’t they warn the pigeon? Or should they not interfere?
At that instant, the tiger sprinted and pounced.
Miraculously, the pigeon flew up and away, finally perching in a distant corner of the enclosure.
Sophie was relieved. Tom was disappointed.
‘I never get to see anything cool,’ he huffed.
Mr Nightingale appeared behind them.
‘What are you moaning about now, Tom?’ he asked.
They explained what had just happened and pointed out the pigeon.
‘Ah, I see,’ said Mr Nightingale. ‘I’d better try to get it out, I suppose.’
‘Did you see him flash his teeth as he pounced?’ Sophie said to Tom.
‘Yeah,’ said Tom, his eyes wide.
‘Any . . . dental problems or issues?’ she asked, looking down at her map and holding up her pen.
‘Er, ah, I don’t think so,’ said Tom. ‘I was kind of looking at the pigeon.’
‘So you two are dentists now?’ Mr Nightingale said with a smile. ‘Well, don’t you worry about Ziggy the Tiger. His teeth are one hundred and ten per cent healthy.’
Sophie put a red circle around the tigers’ enclosure on her map and said, ‘All done!’
Chapter 4
Over the next six Saturdays, Tom and Sophie took photos, kept journals and drew sketches. They assembled a huge number of pictures and descriptions of animals’ teeth.
They hadn’t thought much about teeth before; now they realised that, for most animals, teeth were a matter of life and death. They could be used for so many things – for chewing food, for defending yourself, for building your home, for carrying your young, for attracting a mate, for digging, for climbing, for lifting . . .
If your teeth weren’t strong and healthy, then you wouldn’t last long.
For the first couple of weeks, Tom and Sophie had nothing to report. The zoo animals were eating well and nobody’s teeth were loose or wonky or a funny colour.
However, on the fourth Saturday, the Tooth Sleuths took on their first case. They were in Nightzone, visiting the bats. Bats were still among Tom and Sophie’s favourite animals – ever since they had helped to rescue a baby bat a few months before.
This time now a different nocturnal animal caught their attention – Sammy the rat.
They were pressing their noses up against the rats’ enclosure, watching them scampering along the branches and scuttling through the woodchips.
Tom was muttering to himself.
‘What have you spotted, young assistant?’ Sophie asked.
Tom replied, ‘Hang on – I’m the dentist, you’re the assistant.’
‘No, that was last week,’ Sophie said. ‘This week I’m the dentist.’
Tom sighed and said, ‘OK, doctor, I noticed that Sammy’s chew toy is stuck under a rock. So he’s got nothing to gnaw on and that could cause him tooth problems.’
‘So that’s why he didn’t rush to get his food when the keepers put it out,’ Sophie said. ‘His teeth are probably overgrowing. Remember that rodents’ teeth grow constantly.’
‘Er, sort of,’ said Tom.
‘Rats’ teeth grow their whole life,’ Sophie continued. ‘They never stop. In a year, their incisors – that’s their front teeth – can grow up to twelve centimetres. That’s longer than your fingers. Every year!’
‘A sabre-toothed rat! Cool!’ said Tom.
‘No, no, that’d never happen,’ said Sophie. ‘For a start, they grind their teeth constantly. To file them down. That’s why they get branches and wood blocks and chew toys. But that’s not the main reason you never get a sabre-toothed rat.’
‘What is then?’ Tom asked.
‘Well, it’s a bit sad but . . .’ Sophie said.
Tom looked worried. ‘How sad?’
‘A rat’s teeth curl backwards if they grow too much,’ Sophie said, ‘so they only need to grow an extra half a centimetre before the rat finds it hard to eat. The rat will die long before its teeth start sticking out of its mouth.’
Sophie had drawn a sketch on her pad of a rat’s teeth curling backwards.
‘So you think that could happen to Sammy?’ Tom said. ‘He’s lost his favourite chew toy so his teeth are starting to grow backwards and he can’t eat?’
‘I’m sure of it,’ said Sophie, tapping her picture.
‘We’ve got a serious crisis on our hands!’ declared Tom.
‘We have to remain calm,’ said Sophie. ‘Remember, Dr Sharp always remains calm. Even when he’s got his arm in a hippo’s mouth.’
‘But Sammy could drop dead any minute!’ exclaimed Tom. ‘Imagine your teeth being a metre long and growing down your throat!’
‘I read in a book that it’s quite easy to trim a rat’s teeth,’ said Sophie. ‘We just have to find a zookeeper.’
They spotted Terry the Nightzone keeper in the Malagasy jumping rat enclosure, scattering food on the ground. They waved at him and beckoned him over.
‘Hello, you two. What’s up?’ Terry asked, when he’d clambered out of the enclosure and emerged from a door marked ‘ZOOKEEPERS ONLY’.
Sophie quickly explained that they were trainee dentists and that Sammy was in trouble.
Tom added that Sammy’s teeth could grow down his throat and out of his back, sticking out like spears, and they might even stab other rats nearby, killing them too.
‘Really? Sounds serious,’ said Terry with a smile. ‘Well, I did notice that Sammy was off his food yesterday. I was going to leave it one more day, then call on your mum. But I think you’re right – it’s his teeth. Let’s take a closer look.’
Tom and Sophie followed Terry through the door reserved for zoo staff and were soon standing behind the rats’ enclosure. Terry opened a small wooden panel and reached inside. After a bit of rummaging, he pulled out Sammy.
‘Who wants to hold him?’ Terry asked.
‘Me!’ Tom and Sophie both exclaimed.
‘I should have known,’ Terry said. ‘OK, you can both have a go. To decide who goes first, answer me this. Roughly how many rats are there in the UK?’
‘A million,’ said Sophie.
‘Ten million,’ said Tom.
‘Tom’s closest,’ said Terry. ‘It’s actually eighty million. There are more rats than human beings. So he goes first.’
Tom was so excited, he fumbled and nearly dropped Sammy.
‘This is precisely why I should have gone first,’ said Sophie.
But Tom calmed down and held Sammy firmly but gently. Terry opened the rat’s mouth and looked closely at his teeth. Sophie peered in too. Terry nodded and said, ‘It’s his bottom teeth, look.’
Sophie nodded. They were like tiny tusks, curling around till they almost touched his tongue.
‘What are you going to do?’ Tom asked.
In reply, Terry pulled something out of his pocket.
‘What are they? Pliers or scissors or something?’ Tom asked.
‘Sort of,’ said Terry, holding the tool up so both Tom and Sophie could see it. ‘OK, it’s Sophie’s turn.’
So Sophie held Sammy while Terry snipped off the end of one of Sammy’s lower incisors. Terry flicked the tooth-end on to his palm so Sammy didn’t swallow it. Then he clipped off the end of the tooth next to it.
‘Can I keep these?’ Tom asked, picking up the two pieces of tooth.
‘As long as Samm
y doesn’t want them,’ Terry said with a smile.
Sammy was returned to the enclosure. Terry also pulled the chew toy out from under the rock and put it next to the feeding bowl.
‘Thanks for your help,’ said Terry, ‘again.’
Chapter 5
After a few weeks of being Youth Tooth Sleuths, Tom and Sophie felt that they had learned all there was to know about teeth.
‘Maybe we should get into something else now,’ Tom said. ‘Eyes or fingers or something.’
‘We haven’t had any tooth mysteries to solve for at least two weeks,’ said Sophie, nodding. ‘I think maybe the animals’ teeth will be fine without us.’
‘We’ve been pestering the zookeepers about teeth too,’ said Tom. ‘Now they’re looking out for tooth problems even more than we are.’
So, as Tom and Sophie walked across the picnic lawn at the zoo, they agreed that their work was probably done and that the animals didn’t need their help any more in the dental department. They decided to celebrate with two hot chocolates plus squirty cream.
The tigers’ enclosure was on the way to the cafe, so they stopped briefly to check out Ziggy.
He was lying on his side, yawning contentedly, about two metres away from where they were standing.
‘Are tigers bigger than lions?’ Tom asked.
Sophie nodded. ‘They’re the biggest cat. Siberian tigers can be over three metres long. That’s bigger than a lion, a leopard, a jaguar, a cheetah, a puma, a serval, a caracal, an ocelot, a margay, a lynx and an oncilla.’
‘Are they all types of cat or did you make some of them up?’ Tom asked.
‘They’re all real cats,’ said Sophie, ‘though some of them might not exist for much longer.’
‘What do you mean?’
‘Well, a lot of cats live in forests and jungles,’ said Sophie, ‘and people keep chopping them down. There used to be thousands and thousands of Sumatran tigers. Now there are fewer than four hundred in the wild.’