They are highly adapted to living undergound.

Most of the borrow is composed of

foraging tunnels, which if you add them up can

extend for 3 or 4 km, so massive, massive labyrinths

but because those tunnels are dug

searching for roots and tubers,

their food resources

they tend to be at the level of the roots so within half a meter

or a meter of the

surface. The more central core areas of the burrow

where you find communal nesting chambers and

communal toilet chambers, they

can be deeper.

Once in Kenya we dug down to a nest chamber, it was about 5 feet

underground, which is

quite a lot of digging

clearly, that's difficult for predators to get at

even the snakes that can get into burrows

and I think

also is very thermo-stable

down at that level as well

which is good for these cold blooded

mammals.

The original

founder stock

came form Kenya.

They were collected by someone who did a PHD

in the wild, on their ecology and behavior and they brought

some animals back to London.

Their lifestyle was really the first thing that intrigued

biologists going back to the late seventies, early eighties when it was realized that

the naked mole rat actually

behaved like a social insect.

We have animals living together in very large groups

on average, you know

eighty to a hundred in the wild, sometimes up to three hundred though

yet within these enormous colonies

there is just a single breeding female,

the Queen, she mates with one or two maybe three reproductive males that

she selects and then the rest of the colony of both sexes

are reproductively suppressed,

they help basically.

Some of the bigger ones may

become non workers and adopt a defensive role

so in the non-breeders if you

take a male and a female out the surpressing influence of the colony and

pair them togther away from the suppressing infefluences of the queen

they will quite rapidly

become reproductively active.

The work has

broad implications in understanding

captive breeding and

reproductive suppression in other species and even may be in humans. The

mechanisms are probably

likely to be very similar.

So the queen generally has an elongated body.

After having a few, the first few litters the vertebrae

get longer

to help

accommodate these large litters, she is also

the one that normally

tramples over the top of everyone else when they meet in

the tunnels

on face to face encounters.

She's probably in the first

twenty or thirty days of pregnancy

maybe halfway through the seventy two days, so the pregnancy is actually quite

long for a rodent as well.

Towards the end

when the queen is very very

large and pregnant

because they can have

twenty-seven offspring in one litter, she would have a great difficulty in

getting down, especially the smaller tunnels in the wild

and would be dependent on the work-force bringing

food back.

You can see that although they are called naked mole rats,

they are not in fact completely naked because they have

sensory whiskers scattered along the body

which gives them an important tactile sense, given that they are

living in

total darkness. If we get this one to turn round

head on that you can see the

teeth that protrude

outside the mouth, those front incisors which is what they use to dig

the burrows

and the

mouth seals behind them so that they don't swallow soil as they are digging away.

The external ear is also absent.

Their gut contains quite a

potent mixture of microorganisms which helps them to

ferment the high cellulose content of the food

also gives rise to

one of the more unpleasant aspects of mole-rat behaviour which is Coprophagia

so when the young are being weaned

they eat the faeces of the adults in order to infect their

digestive tract with these all important microorganisms.

Some of the animals we can see here

will be over 20 years old

and going strong. The last time I asked a colleague in the States, she had some

at

about 32 years

so we probably don't know the upper limit just yet.

Another thing

was that they appear

not to get any of the usual age related problems including Cancer.

Recently, there has been 2 separate naked mole-rat genome projects and

so far

the genome project has

revealed that some of the

genes that we would expect; cancer, genes related to low oxygen,

genes that are implicated in aging, have been shown to be doing different things in

naked mole rats. It will have wide ranging for implications for human and

and animal health, and understanding Biology in general.