The COVID-19 outbreak started with bats.
Many deadly viruses in the past have also originated from bats, including the Ebola outbreaks in Western Africa.
(SOUNDBITE) (English) MEMBER OF WORLD HEALTH ORGANISATION-LED TEAM IN WUHAN, PETER DASZAK, SAYING: "How did the virus get from bats in some of other part in China or Southeast Asia into Wuhan?"
Molecular studies have demonstrated that bats are natural reservoirs to many different viruses, some of which have led to disease outbreaks.
So why is that?
Bats are a group of flying mammals with more than 1,300 different species in 20 families. That's according to the International Union for Conservation of Nature.
Some bats roost in forests while others in caves. Some eat insects; some fruit, seeds and pollen; while others eat small animals such as birds, fish and frogs. Some even feed on animal blood.
Hello, vampire bat.
The diversity of the group has been seen by scientists as a possible mechanism for driving virus diversity.
And studies have shown that bats host more zoonotic viruses per species than even rodents, the most diverse mammal group.
Apart from diversity, other traits that make bats suitable as virus hosts include their size and longevity.
Bats have relatively long life spans for their body size, which can make it easier for viruses to persist.
Bats are the only mammals capable of powered flight, which has a high metabolic demand.
This leads to elevated body temperatures in bats, similar to the effects of human fever that occurs during immune response.
This means some viruses they carry have adapted to be more tolerant to higher temperatures, potentially bad news for other animals if infected.