Spectral tarsiers in a ficus tree in Tangkoko Batuangus Nature Reserve, Indonesia

All eyes on biodiversity

We don't really need an excuse to celebrate wildlife, but today is the UN's World Wildlife Day. This year's theme is Sustaining all life on Earth, focusing on biodiversity. The UN and its partners are producing a series of programmes and social media activities, including a film festival and an international youth art competition.

Tangkoko Batuangus Nature Reserve in Indonesia is a great symbol of biodiversity, protecting hundreds of species of plants, mammals, birds, reptiles and amphibians. Among the threatened mammals here are these spectral tarsiers. These small nocturnal primates have eyes that are larger than their brains, giving them an alien-like appearance. They're not in imminent danger of going extinct but are classified as vulnerable, and their population has decreased due to human activity and habitat loss.