Through the shady trunks came a huffing squeal and something huge moved painfully into view. To Janer it looked like a lizard made in the shape of a buffalo, but with some extreme differences to either creature. It did not have hooves or claws, but huge flat pads; the horns on its head were repeated in rows along its neck, and it had no tail. Janer mistook it as being four-limbed until he spotted the mandible limbs folded under its three-cornered mouth. Its tough hide was heavily pocked and Janer realized that the circular marks he had assumed were scales, were in fact healed leech scars.

The creature lumbered on past, flinging only a glance at them with its single double-pupilled eye. At the shoulder, it stood twice the height of a man and seemed a formidable creature. That it was a vegetarian, was evident when it halted by one of the thorny trunks and ground a lump out of it with its serrated mandibles. The vibration this caused had leeches falling on to it out of the tree. They immediately attached themselves and bored into its back. It grunted on finishing the mouthful it was chewing, then turning its head each way it used its mandibles to pull off any leeches it could reach. It then champed another mouthful - and more leeches fell.

‘We’ll go round,’ said Ambel.

‘Is that thing dangerous?’ asked Janer, his carbine held in readiness.

‘No, but they are,’ said Pland, pointing to the leeches wriggling on the ground or oozing back up the tree trunks.

‘What is it?’ Janer asked Erlin, as they gave the huge creature and the rain of leeches it was causing a wide berth.

‘Its name? I think it’s called a tree pig or something.’

‘Wood pig,’ Pland corrected her.

She nodded and went on, ‘It’s one of the heirodonts. There’s thousands of different kinds - some no bigger than a pin head. That’s one of the largest types you’ll find on land. It’s rumoured there are oceanic ones that grow larger, but that’s never been proven,’ she said.

‘Does it have any predators?’ asked Janer, wondering about some of the sounds he’d heard in the night.

‘There’s only two predators here on land: us’ - she pointed up into the foliage - ‘and them.’

‘Why only two?’

‘The leeches and the virus evolved together. There may have been other land predators at one time, but the leeches left no room for them. I’d guess that the leeches took to the sea only a few million years ago, so that’s why you find other predators there. Give this place another couple of million years and there’ll be nothing in it but vegetation, herbivores and leeches.’

‘A grim prospect.’

‘It’s life,’ said Erlin simply.