Extinction: the animals we have already lost

Extinction is a fact of life. Species evolve to suit the climate, terrain and resources that surround them, and when those conditions change, they either adapt or die.

It can happen at any time, but geologists say there have been five previous periods of mass extinction in our planet’s history, when conditions changed so drastically or so quickly that a multitude of plant and animal species perished.

At least they died a natural death, the victims of unstoppable forces, from meteorite collisions to drastic global climate change. And we know that humans were not responsible for the changes that lead to their demise, because humans were yet to walk the Earth.

But that’s not true of what some experts term the sixth mass extinction, the one that started when humans first began to disperse across the globe 100,000 years ago, and which carries on to this day. This is mass annihilation caused by pollution and manmade climate change, the over-exploitation of natural resources and the introduction of alien species. There’s no denying our culpability.

The price for our domination of the Earth and its resources, in other words, is being paid by the natural world. Thousand of species are threatened, and thousands more have already been wiped forever from the surface of the planet.

Here are some of the weird and wonderful animals that have been lost already – along with one or two that are teetering on the brink - and the factors that brought about their downfall.