because they live a really long time

and that's really unusual for a mammal of that size.

So a mammal of that size usually lives one to two years

and bats can live up to 40 years which is amazing.

They have a really interesting repair mechanism for their DNA,

so they can repair all the DNA that is broken and they never get cancer.

Bats are very resilient animals.

They also have a number of adaptations

that make them very good at surviving in harsh environments.

Bats use loads of different senses.

So bats use their eyes, so they're not blind,

but they also use sense of smell.

So they have big smell regions of their brains

when they need to find food.

The primary sense that many bats use

is echolocation, or sonar in human terms.

Although the bats have been using these signals for 50 million years,

we've been using them for maybe 100 years.

We also need to be operating on our senses.

We have to operate on our gut feeling a lot of the time.

Jungles are probably the best place

for having to use your senses constantly

because they're hot, they're humid, dark.

So you're almost feel a bit like a bat, very claustrophobic.

And you have to be aware of the little changes.

So when things go quiet, potentially there is a predator in the area.

Bats, very often, live in very large colonies.

Very often these colonies contain millions of individuals.

One of the largest aggregations of mammals on the planet

is a bat roost in Texas in Bracken Cave.

We don't really know how many there are

but it's between 10 and 20 million bats that live there.

This colonial way of life has several advantages.

So bats can keep each other warm

and reduce energy costs by huddling together.

Another advantage of being in a group

is it reduces your individual risk of being eaten by a predator.

So bats live in large communities,

they have to get on with lots of other people

and on expedition we can be in a large team.

So building relationships, sustaining those relationships,

developing systems for living in a community,

generally away from normal society, bit like the bats,

and therefore we have to develop our own ways

of supporting each other,

looking after each other, teamwork,

using the collective mind to be aware of danger

or to enable us to actually do the tasks that we're going to do.

Bats don't just care about their own blood relatives,

they care about other individuals in their wider community too.

They form these buddy pairs

and if you don't find a meal for that night

you can ask your buddy to share what they have for that night

and then the next night you can reciprocate.

So it's called reciprocal altruism,

one of the very few examples of reciprocal altruism

in mammals in the entire world.

So bats are often covered in quite large numbers of parasites.

The bats get rid of parasites, in part, by grooming.

Not only do they groom themselves

but very often they do something called allogrooming

where individuals groom one another

proving social bonds among individuals in colonies.

Bats are well known for their personal hygiene,

their levels of personal hygiene.

The dark, dank bits need to be cleaned on a regular basis,

and also you need to be aware

of your cleanliness, particularly around other people.

It can ruin relationships,

particularly if you're sharing a tent with them for a period of time,

and your ability to continue doing the expedition.