Last Night's TV: Polar Bear: Inside Nature's Giants Special/Channel 4<br />Dance! The Most Incredible Thing about Contemporary Dance/BBC4

How's this for a fact? Polar bears are so fat that even if they don't eat for eight whole months they'll still be fine. They're practically supermodels! Or this: their penises have bones in them. Huge ones. Giant white pieces of calcium.

Even by its own high standards – and they are high – last night's Inside Nature's Giants was spectacular. The start of a new series, it saw the team booted out of their usual dark laboratory and into the startling, round-the-clock light of Greenland. The idea was to find a polar bear (or several) on whom to do their usual cut-and-delve. The thing is, they can't just go to a zoo because, this time, they're looking at something more than just anatomy. Recent reports of species abnormality have led scientists to believe that pollutants are contaminating the Arctic waters. So, together with a group of Danish scientists, Mark Evans et al want to know what the problem is. And they can't just find a dead bear lying around: not only are polar bears extremely difficult to spot (on which more later) but they are highly prized as hunting bounty by the local community. Though the quotas are strictly regulated, polar bear hunting is still permitted as a traditional subsistence practice.

Speaking of which: imagine living in Greenland! I can tell you this much: you wouldn't get your five-a-day. It costs £10 for a head of broccoli, so foreign a delicacy is it considered (leeks are relatively cheap; just £3 a pop). Chocolate seems to be the must-eat food, a sure-fire way of keeping warm. Before that, it was polar bear meat. Back when the first settlers arrived on the north-east coast of the island, long before imported veg and global warming, there were plenty of bears to hunt. They ate the meat and wore the skin: a trip to the local museum (Greenland's must-see tourist attraction) revealed an old outfit made of bear fur and sealskin, a kind of all-encompassing busby.

At any rate, all of this means that getting hold of a bear carcass was a tricky balancing act. Though they're offering a reward in return – and promising to salvage all edible meat – it's a disruption of local traditions, which hinge on sharing out the meat at the place of death. Still, eventually they get their prize, a youngish male, complete with giant penis-bone, brought in by the region's youngest hunter. And so begins the dissection: a giant bloody operation on the icy table of the Arctic.

First, the fur. No wonder it makes good gloves. So well equipped is it at insulation that bears are almost impossible to spot using infra-red technology: they lose next to no heat. Looking inside one is like looking inside one of Gillian McKeith's patients. They are what they eat. And, a lot of the time, they eat just that: fat. They kill seals for their blubber and leave the rest, and they are, as the good "doctor" would no doubt tell you, a cholesterol disaster waiting to happen. Except not, because they have a super-bear-sized gall bladder full of brine to sort it all out. Everything about them is ideal for their environment, from their tiny, warmth-retaining ears (quite literally, the opposite of the elephant's giant flaps) to their funny-shaped heads.

It's thought that they evolved from a group of brown bears when the ice age left them stranded in Siberia. Instead of your archetypal teddy-bear skull, a sleek, streamlined helmet evolved to help them fish for seals. As usual, Richard Dawkins is on hand to explain it all: the clever little processes that make nature work. And that bone. "I have a little theory about this," he giggled, a schoolboy trying out a dirty joke. Plenty of mammals have bones down there – humans are the odd ones out. The thing is, boys, maintaining an erection when you've got a giant bit of skeleton to hold it up is hardly an impressive sexual feat. It's possible, he thinks, that menfolk have evolved away from it in an attempt to impress the ladies. Classic case of getting us wrong.

The bad news is that there is, it seems, something wrong with the water. A second bear inspection – this time of a fully grown female – revealed a series of reproductive disorders that point to that. Whether their findings will make much difference remains to be seen, though the scientists, at least, are confident. "This is stuff that affects government policy," said one. Which is the least convincing argument I've ever heard.

Having watched Dance! The Most Incredible Thing about Contemporary Dance, I find myself wondering what, in fact, is the most incredible thing about contemporary dance. It's a surprising development, since I've never wanted to know before, but – what can you do – suddenly, it's consuming my consciousness. Is it the splits? The jumps? Or is it the fact that someone thought it a wise idea to make an entire programme about the Most Incredible Thing About Contemporary Dance? Because that's pretty incredible.

The conductor Charles Hazlewood has been given the unenviable task of discovering said phenomenon; he seemed rather most disposed to enjoy it than I was. He interviewed lots of experts, lots of choreographers, even did a bit of dance himself, but none of it seemed particularly incredible. Except the moves, which are impressive. But that's just dance, isn't it? We knew that already.