Animals could start shrinking because of global warming, scientists have predicted, after discovering that mammals became ‘dwarfed’ in a similar episode of climate change 50 million years ago.

Paleontologists discovered the fossil teeth belonging to an early ancestor of modern horses as well as a rabbit-sized hoofed mammal.

The teeth revealed that during Eocene Thermal Maximum 2, a warming event of around 3C that occurred approximately 53.7 million years ago, the animals shrank in size by 14 per cent.

Climate researchers currently estimate that the planet will warm between 2C and 4C by 2100.