Upstairs, Tom and Sophie found themselves in a large white room full of vivariums of all shapes and sizes. They were arranged in five long rows.
They saw coral snakes and corn snakes, rat snakes and rhinocerous snakes, copperheads and keelbacks.
‘So why aren’t these snakes on show?’ Sophie asked.
‘All sorts of reasons,’ said Daisy. ‘Maybe we’ve already got one on display. Maybe we haven’t got the right vivarium for them. Maybe they’re hibernating. Maybe they’re pregnant. But, you know, we still love them.’
Tom was staring at a gigantic constrictor in a long clear enclosure.
‘That’s Bessie,’ said Daisy. ‘She’s twelve metres long. That’s probably eight times longer than you! And I think she’s hungry.’
Tom took a small step back.
‘Don’t worry, I didn’t mean she’d eat you,’ said Daisy. ‘I mean it’s time to feed her. Want to help?’
Tom and Sophie both grinned and said, ‘Yes.’
They spent the next hour helping Daisy with a variety of tasks.
First Tom fed Bessie, dropping a whole defrosted turkey, feathers and all, into her enclosure. They watched the snake stretch her mouth around the bird and swallow it whole.
‘She’s dislocating her jaw, isn’t she?’ Sophie said.
‘Not quite,’ Daisy said. ‘Her jaw’s on a hinge so she can swing it all the way back. Then she has a tendon in the middle of her chin that can stretch sideways till it’s wider than her body.’
‘Why doesn’t she just chew it?’ Tom asked.
‘Her teeth are too small to chew anything,’ Daisy said.
‘But doesn’t she have massive fangs?’ Tom asked.
‘No, she’s a constrictor,’ Daisy said. ‘Only snakes with venom have true fangs. Even if she did have them, most fangs are hollow – so they can squirt venom through the middle. You know, like that needle Gavin was holding? They’re no good for mashing up food. Having said that, she still has quite a set of teeth on her and you wouldn’t want her to bite you!’
They watched for five minutes: three-quarters of the turkey was still sticking out of Bessie’s mouth.
‘You can stay till the end if you like,’ Daisy said, ‘but it may take her a couple of hours to swallow it. You know, Bessie could eat something much bigger than that – even something as big as a Labrador!’
Tom and Sophie stared at the turkey in Bessie’s mouth for a few seconds more. Then they followed Daisy to the next vivarium where a corn snake was coiled up in a corner.
‘This is Shaun,’ said Daisy. ‘He’s having problems shedding his skin.’
Daisy looked in and saw a strip hanging from the side of his body.
‘That’s why I put that big pool of water in his vivarium,’ said Daisy, ‘but I think we might need to give him a bit more help.’
She reached under the vivarium and pulled out a branch. She offered the branch to Sophie and opened the top of the vivarium.
‘Put the branch in his pool of water. He’ll be able to rub himself against that and nudge his skin off.’
Sophie hesitated.
‘It’s OK,’ said Daisy. ‘He’s a constrictor too. Won’t bite. And he’ll only constrict you if you look like and smell a rat.’
‘Watch out then, Soph,’ Tom said.
Sophie ignored him and put the branch in the vivarium.
‘How often does he shed?’ Sophie asked, watching Shaun slide towards the branch.
‘Every couple of months,’ said Daisy.
‘Why do they do it?’ asked Tom.
‘Because snakes keep outgrowing their skin,’ Daisy said. ‘They’re not like us. They don’t get to eighteen and stop. They grow their whole lives. And their skin doesn’t stretch. If they didn’t shed their skin, they’d burst out of it.’
‘That would be way better,’ said Tom.
Next Tom and Sophie helped to clean out a vivarium. Daisy removed the snake with hooks and placed it in another enclosure. Tom and Sophie learned that each vivarium had a heat mat at one end of it, so that the snakes had a hot part (to warm up) and a cold part (to cool down).
‘Snakes can be pretty slow in the morning unless they get to a certain temperature,’ Daisy explained.
Tom and Sophie changed the substrate on the vivarium floor – pouring in fresh woodchips from a large bag. They also learned how to fit the vivarium lid on securely.
They were looking at a mangrove snake called Clive when Daisy’s radio started to crackle.
‘Hello, this is Reptiles,’ said Daisy. ‘Yep, yep, on my way.’
She turned to Tom and Sophie.
‘Bet you want to see those snakes you rescued yesterday,’ said Daisy.
‘Yes!’ exclaimed Tom and Sophie.
‘Well, that was your mum,’ said Daisy. ‘They’re about to operate on a green mamba. Want to come along?’
Two minutes later they were walking through the zoo on their way to the hospital.
At the door to the hospital they met Gavin again. His big glasses were squares of light in the sunshine.
‘We’ve got some students in from the Royal Veterinary College so you can stand with them in the observation room,’ he said, as he opened the door and ushered them inside.
‘Will I get a lamp on my head?’ Tom whispered to Sophie excitedly.
‘We’ll just be watching, not operating,’ Sophie replied.
‘Do you think the mamba will need LOTS of stitches at the end?’ Tom asked her.
‘Very possibly,’ said Sophie.
As they walked into the hospital building, both Tom and Sophie looked around. They’d visited their mother’s workplace a few times before, but it still felt like a strange and amazing place.
They passed one treatment room where a vet was peering up a coati’s long droopy nose. In the next room, another vet was gently lifting a pelican’s wing.
Tom hovered in the doorway of the third room. A vet was unlocking a cabinet, and then unlocking another door inside the cabinet. She pulled out a tranquilliser gun.
‘What’s she going to shoot?’ Tom asked Gavin, as Sophie pulled him away.
‘Nothing,’ said Gavin. ‘She just needs to practise. Shooting a dart into an animal is very tricky. You can be quite some distance away. And you have to hit muscle, not bone, or it can really hurt the animal. So all of us practise on a regular basis.’
‘Not Mum, though?’ Sophie asked.
‘Of course your mum!’ said Gavin. ‘She’s an excellent shot.’
Tom and Sophie looked at each other. Daisy leaned in and said, ‘Better do what she says in future, eh?’
Now they had arrived at a large room next to an operating theatre. There were three white screens on one wall, lit from behind by small bulbs.
A split second later, Sophie and Tom’s mum walked in, holding a series of X-rays. There were three veterinary students behind her. Their mother already had scrubs on – a gown, hat and mask. She had pulled her mask down under her chin and was explaining something to one of the students.
Mrs Nightingale looked up and smiled at her children, then carried on talking.
‘So next up: Gareth the green mamba. Let’s have a look at these X-rays,’ she said, pinning five of the films side by side on the white screens.
‘Normally you just have one X-ray,’ Daisy said quietly to Tom and Sophie, ‘but with snakes you have to take one, then move the snake along, take another, move the snake along. Till you’ve X-rayed all of him. Then you stick the X-rays together.’
‘So what’s eating Gareth?’ Mrs Nightingale asked. ‘Or what’s Gareth been eating?’
The three students peered at the X-rays. Sophie stood on tiptoes and looked over their shoulders.
A large white circle was visible about halfway along Gareth’s body.
‘Is it a retained egg?’ one of the students asked. ‘Maybe she laid all the others, but not that one?’
‘Can anyone tell me why that’s unlikely?’ Mrs Nightingale asked.
The students all looked at each other and then back at the X-rays.
‘Because Gareth’s not a girl,’ Sophie said quietly.
‘That’s right!’ exclaimed Mrs Nightingale. ‘The clue’s is in the name.’
The students looked at Sophie, and Sophie blushed and looked at the ground.
‘Any other guesses?’ Mrs Nightingale asked.
‘Does she – sorry, he –’ began another student.
Everyone tittered.
‘Could he have a tumour?’ the student asked.
‘That’s a better suggestion,’ said Mrs Nightingale. ‘Anyone agree with that?’
The other two students put their hands up, then put them down again, then put them up again.
‘It looks too solid for a tumour,’ one of them eventually said.
‘Plus, does he have any other symptoms of cancer?’ Mrs Nightingale asked.
The students all shook their heads.
‘Which leaves . . . ?’ Mrs Nightingale asked.
‘A foreign body,’ said one of the students hesitantly.
‘Correct!’ Mrs Nightingale said. ‘It looks to me like it could be a stone. So can anyone tell me why this most intelligent of creatures has swallowed a stone?’
‘Could he have thought it was a bird’s egg?’ one of the students asked.
Mrs Nightingale smiled and shook her head.
Sophie had an idea, but bit her tongue. Daisy could see that Sophie wanted to guess, so nudged her. ‘Go on,’ Daisy said, ‘she won’t bite. She ain’t a mamba, is she?’
‘Maybe,’ stammered Sophie, ‘maybe he was swallowing his prey. You know, a rat or whatever. But there was a pebble in his enclosure. Underneath the rat. And he swallowed both at the same time. By mistake.’
The students all looked impressed. ‘Yeah,’ one of them said, ‘it has to be that. Definitely.’
‘That is the right answer,’ Mrs Nightingale said. ‘Well done, Sophie. Everyone, this is my daughter. And that’s my son, Tom. Be nice to them and I’ll give you all a distinction.’
The students all said hello and smiled.
‘OK,’ Mrs Nightingale said. ‘Gavin, Daisy, time to scrub up.’