Last Night's Television: Could You Eat An Elephant?, Channel 4The Secret Life of Elephants, BBC1

"There's something about a little bird that says 'lunch'," Fergus Henderson mused in Could You Eat an Elephant?, picking bits of thrush from between his teeth. "It's nature's portion control." It's also nature's way of saying "Don't eat me" if you happen to be British, where a love of songbirds does not traditionally encompass fricasseeing them in a fresh tomato sauce and then crunching their tiny skulls between your teeth so you can suck the brains out. But then Fergus and his chef mate, Jeremy Lee, weren't in Britain. They were in Italy, attempting to map the arbitrary line that different cultures draw between the delicious and the disgusting.

Fergus and Jeremy are perfectly qualified for this task because they are both champions of "nose-to-tail eating", never likely to turn their noses up at a boiled pig's head or a duck's gizzard. So they were hardly going to be phased by thrush. They even invented a new dish for Italian enthusiasts: the thrush pizza, which Fergus, a natural comedian, introduced with his own distinctive approach to speaking foreign. "Noovo... er... approach?" he said hopefully, adding a few expansive hand gestures for good measure. Marcetto cheese, which only Jeremy turned up to sample, was a far tougher prospect: a fly-blown pecorino that is only deemed ready for consumption when the maggots are so numerous they're about to walk it off the plate. "Phwooahr!" said Jeremy, eyes watering after a sample bite. "It's quite a flavour."

Marcetto is slow food – patiently ripened to the point of putrefaction – but in Vietnam, the two men went to a fast-food restaurant specialising in snake. Thirteen dishes were carved out of a cobra in just seven minutes, though the cobra fought all the way to the wok, the whole banquet kicking off with the still-pulsing heart delivered to the table in a shot glass of vodka. Both diners insisted that fried snake bones were delicious and the cobra spring rolls "fresh as a daisy" but they had mixed views about the bile cocktail. They weren't too keen to eat sewer rat either, though by then a muddying complication had entered the picture, with taboos about what you can legitimately eat clashing with taboos about what you can legitimately do to animals before you eat them. Both men were prepared to sample beetle pâté in the Kalahari, but clearly hated pulling the wings and legs off first. "Something happened," said Fergus quaveringly, after his hosts had insisted he help with the prep. "It was emotional. For me and the beetle."

Fergus – wearing bottle-bottom glasses and a look of dazed amusement – was brilliant, stalwart in the face of the barely edible and never at a loss for a dry joke. "Oh, that's congealed beautifully," he said as a noisome swill of stewed dog intestine was delivered to the table in Vietnam. But he was also soft-hearted. Both men did their best with the dog banquet, but then looked as if they very much wished they hadn't when they saw how the stock was treated at the dog farm. And from there onwards, their commitment to omniverousness effectively died. Fergus was sympathetic to the Kalahari tribesmen who regarded elephants as five-ton rats ("I wonder if it affects property prices this side of the village," he said, being shown the trail of one recent invader) but flatly refused to join in the feast when a supply of fresh elephant became available. "They party, they love each other, they have memories... I tried to be open-minded but I wasn't," he said, and he became even more agitated watching monkeys being prepared for the pot. "It's just not on, it's just not on," he said. But if not, you wondered, why is any meat-eating? What has the noble pig done to forfeit our forbearance?

I hope Fergus saw The Secret Life of Elephants, which will have confirmed his conviction that they are too tender to be turned into meat. Not everyone shares this view, naturally. Ask a crocodile or a lion whether they could eat an elephant and they would reply, "Yes, smashing, but just a baby one please. Nature's portion control." This brutal truth of life in Kenya's Samburu reserve delivered the necessary narrative tension to the first episode of BBC1's pachyderm Big Brother, in which a winsome little baby called Breeze had to be protected from various hazards by the rest of the herd, as it staggered around like a pantomime cow with a drunk trapped in the back legs.

Much was made of the human-like bonds of trust and love that can be found in these family groups, although it didn't seem to stop some elephants falling through the cracks in the welfare system. "Unable to keep up with the herd, they have become separated from their family," the voice-over noted plangently of one mother and her crippled calf. Or, to paraphrase, "The herd have left the losers behind."Lovely film, though, even if a whole hour felt like slightly too generous a serving of elephant.