so in the wild naked mole-rats are subterranean they live underground in a large tunnel-based
system with several chambers so they have nesting chambers as well as a toilet chamber and we try to
recreate that in the lab by making a series of cages some small some large that are connected
by tunnels of different lengths we provide them with bedding material we provide them with same
sorts of food they have access to in the wild and then enable them to make their own nests they'll
always establish their own toilet chamber from a looking after them point of view it's really
good but one cage becomes dirty very quickly and the others stay quite clean so you can maintain
changing one cage regularly and you only have to change the entire colony less frequently which the
animals like the animals in the wild would spend their time excavating tunnels with their teeth
and obviously we provide them with tunnels and we provide them with caging because it's
important for us to be able to look at and report on the health status of every individual every day
so if we have a room full of mud the animals might be able to dig tunnels but we can't see
what states they're in so we do provide them with different types of tube blocks so that they can
gnaw away at things and the thing we provide them to enrich their environments that they certainly
don't have in the wild are running wheels now no one makes toys at a naked mole-rat size
and naked mole-rats are a bit bigger than a mouse but quite a lot smaller than a rat some
of the mole rats will just be running very very fast for very long periods of time we
don't know why different mole-rats choose to do different things with the running wheels
so in terms of how and naked mole-rats communicate with each other they've got a very diverse vocal
repertoire and so if you go into a naked mole-rat holding room you'll hear almost what sounds like
birds because they've got this chirping noise they'll make but they've got a whole
variety of different squeaks and different chirps they'll make with each other baby mole-rats will
beg for faeces from adult mole-rats and that has a particular vocalisation so it's not just
random squeaking going on there are different vocalisations that mean different things
at least if you're a naked mole-rat so within the naked mole-rat colony you've only got one
female that's able to give birth and if things are going well she'll give birth about once a quarter
so the gestation time for a naked mole-rat is about 72-75 days so the new queen will have
far fewer pups than an older queen so in my experience the majority of first-time mothers
will give birth to somewhere between two and five pups the record for a naked mole-rat queen is 28
here in Cambridge we've regularly had animals give birth to 17-18 pups it's difficult to see
exactly how many given birth because they all look very small and pink and wriggling
all together and because they form these large nests we don't tend to go in and disturb them
so in the wild naked mole-rats are virtually entirely subterranean they live always underground
and they eat tuber-like vegetables in the lab we give them a variety of similar type vegetables
so they get a lot of sweet potato most of the squash family but they eat most things they love
banana they like sweet things like grapes but tuber vegetables their mainstay of their diet
so in the naked mole-rat colonies we give them their cages and tunnels but there's another
factor we really need to consider which that naked mole rats are poikilothermic that means
they're cold-blooded they're unable to control their own body temperature so whereas humans will
sweat to cool down they can't do that they don't even have sweat glands they are able to detect
temperature differences though so for example the animals will always sleep in a bundle altogether
to help conserve heat now where they originate from in east Africa and Kenya Somalia and Ethiopia
when they live below ground in those countries is a very stable climate
so the temperature difference between night and day summer and winter is only about two degrees
so presumably through evolution they just lost the ability largely to thermo regulate so in
the lab we therefore have to look after them very carefully the holding room for the naked
mole-rats is kept at about 30 degrees with a high humidity just like they would have in the wild
so naked mole-rats live in large colonies all together and they're social animals so usually
if an animal is healthy it's engaged in colony activity without running around grabbing food
chirping at the other animals or huddling all together a naked mole-rat that doesn't
look so well will usually be one that looks a little listless so they'll be walking around
in a slightly uncoordinated way they look rather thin and they're not engaging with other members
of the colony so usually a colony that everyone is happy in will be a colony that breeds regularly
if there's sufficient space but also to be a colony where there is no fighting
so naked mole-rats are known to fight amongst themselves and with the teeth they have they
can do a lot of damage so a peaceful colony is one where you don't have any fighting
where everyone sleeps together eats together and it's just running around generally looking
like they're having fun so the thing about how intelligent a naked mole-rat is it's difficult to
know what we mean by intelligence especially when you think about a small rodent versus a human but
I think when we're working with animals something we often think about is do they know who a human
is and do they know who a specific human is and I think when you interact with the naked mole-rats
generally speaking they're quite a friendly animal so you'll pick one up and if you know what you're
doing and handle the animal carefully they don't immediately turn around and bite you and I would
say from when i work with the naked mole-rats and other people in my lab work them I've sort of
spent more time handling them they're more tame in my hands with other peoples
but they're generally quite relaxed as long as you're confident in handling them but I wouldn't
say that any of them are particularly aware that I'm me when I come into work with them versus
anybody else as opposed to being a confident person who works with the animals it's not like my
cats at home who are very much aware that it's me who's come in and they want to come and say hello
so when we've decided that we're going to use an animal for research the animal will
be humanely killed and then we'll harvest the tissue that we want
so that might be for example certain neurons if we're looking at how
the base of pain is different in a naked mole-rat to say compared to a mouse or a human
we might also harvest the skin cells to generate fibroblasts which we can use for cancer research
and I think the important thing for us to bear in mind with naked mole-rats is they're very precious
and significant animals they live for a very long time and they're not as commonly available as mice
therefore we have to be very concerned when we do an experiment to do as much as possible with
one animal so we always make sure that as many different researchers wanting tissue from a naked
mole-rat are present to take tissue for their particular experiments so it's not uncommon when
we harvest tissue that someone may take the heart for experiments looking at cardiac resistance
to problems associated with ageing other people might take the brain we might take certain sensory
nerves working on pain so basically trying to take as many parts of the animal as possible to support
as many different lines of research so from every animal we get as much as we possibly can out of it