It is swelteringly hot and unbearably humid as we set off on our journey deep into the heart of the Dominican Republic's tropical forests.

And as we drive along the bone-joltingly bumpy track, crammed into a truck loaded with enough supplies for our week in the wilderness, the excitement amongst the researchers grows.

We are on our way to see if we can track down one of the most strange and ancient mammals in the world - the Hispaniolan solenodon.

But finding one will not be easy: naturalists once thought that you would be more likely to see a ghost than this elusive creature. And, indeed, few have ever come face-to-face with one.

Image caption The solenodon is one of just a handful of venomous mammals

The nocturnal solenodon, which is only found in the Dominican Republic and in one of the last forested patches of Haiti, is often described as a "living fossil", thanks to the fact that it has been around, virtually unchanged, for the past 76 million years.

Remarkably, this means it would have once scuttled amongst the giant feet of the dinosaurs, in the days when they roamed the Earth.

The problem is that we really don't know anything about these animals Dr Richard Young, Durrell Wildlife Conservation Trust

And it is an odd-looking animal.

It is the size of a rabbit, with a ginger-brown coat. It has disproportionately large, clawed feet, beady little eyes and a very long, thin nose.

But perhaps its most bizarre - and prehistoric - feature is that it is the only mammal that can inject venom through its teeth, the same way a snake does.

The poison, while not deadly to humans, is the perfect tool for the insectivore, allowing it to dine on bugs as it moves around the forest at night.

Last survivors

But this unique creature is now under threat.

The Dominican Republic and Haiti, which together make up the island of Hispaniola, used to have a diverse mix of monkeys, shrews, sloths and rodents, but these have died out one by one.

Image caption The hutia is also one of Hispaniola's last native mammals

This has left the solenodon and a tree-dwelling rodent called the hutia as the only native mammals that remain.

Now, researchers from the UK and the Dominican Republic, with the help of a grant from the UK government's Darwin Initiative, have embarked on a project called The Last Survivors, which they say could be our last chance to save the solenodon and hutia before they vanish from the forests forever.

The programme involves the Durrell Wildlife Conservation Trust, the Zoological Society of London (ZSL), the Hispaniolan Ornithological Society (SOH) and the Dominican Republic's national zoo and environment ministry.

Dr Richard Young, head of conservation science at Durrell, explains: "The problem is that we really don't know anything about these animals - we don't know where they are, how many there are and how this relates to their habitats.

"And before you can start to conserve them, you need to answer some really basic questions."

But, given the suggestion that a supernatural sighting might be more likely than snatching a glance of a solenodon, finding these creatures to uncover the answers is not going to be easy.

And in fact, says Jorge Brocca, SOH's director, few people in the Dominican Republic have ever seen one, and many have never heard of them.

He explains: "We've been showing local people photographs, and most of them do not know what these animals are."

Image caption The Sierra de Bahoruco is topped by a stunning pine forest

We head for the Sierra de Bahoruco, a mountain range in the south-west of the Dominican Republic, which straddles the border with Haiti. At its highest point it reaches an elevation of 2,200m (7,200ft).

As we negotiate the steep incline, we see a spectacular range of habitats - from dry, cactus-studded forests in the lowlands, up to vibrant, cloud forests dotted with giant trees, ferns and mosses, and finally, at the peak, a pine forest, that looks something like a tropical version of Scandinavia.

Here, the team is surveying patches of forest for solenodons - the start of an attempt to get a comprehensive grasp of the mammal's spread across the country.

Image caption Solenodons leave a "nose poke" as they probe the ground for insects

Much of this work takes place during the day, while the animals are sound asleep in their burrows.

As we trek ever deeper into the forest, Durrell's Joe Nunez-Mino, who is working in the field with the SOH's Pedro Martinez and local research assistants Nicolas Corona and Lleyo Espinal, tells me that trying to find them feels a bit like being a detective.

The first clue, he says, is the "nose poke" - he points to one as we tramp through the dense vegetation.

He explains: "These are holes that the creatures make in the ground as they use their long noses to probe the earth as they look for insects."

Nearby, we find what might be the entrance of a burrow.

He bends down and takes a deep sniff inside the cave.

Solenodons, he says, have a really musty smell, a bit like a goat. And sure enough, a pungent odour seeps out of the cave - an exciting sign that one might be in there.

Long wait

But until night falls, the solenodon will remain asleep in its subterranean den, and there is little more we can do here.

So we return to our wooden cabin, set in a small clearing, and feast upon our campfire-cooked meal, waiting for darkness to descend over the forest.

It's going to be one of those life-defining moments to see one in the wild Dr Sam Turvey, ZSL

For the ZSL's Dr Sam Turvey, who works on the Edge of Existence Programme, the prospect of spotting a solenodon is thrilling.

"I cannot tell you how excited I am about seeing one. Being in the middle of the forest, in the middle of nowhere, in the night, is going to be amazing," he says.

"It's going to be one of those life-defining moments to see one in the wild."

We know our chances of finding one might be slim, but with good weather, the expert skills of our local research assistants and a huge pinch of luck, we grow ever more hopeful that we might soon become some of the fortunate few to have come face-to-face with this elusive forest "ghost".