Last Night's Television: Who Do You Think You Are?, BBC1<br />Wildest Dreams, BBC1

"This is going to be another depressing day isn't it," said Chris Moyles, absorbing the latest of the revelations about his family line in Who Do You Think You Are?, "... it's going to be death all day today." Could have been worse Chris. The programme researchers could have come back with the news that your ancestry was so tediously unremarkable that they weren't going to bother filming at all, as Michael Parkinson has just revealed happened to him. And while stories of infant mortality and Dublin slum hardship might bring a lump to your throat you must have known that it would be the sort of thing to get a Who Do You Think You Are? researcher beaming broadly. This is, after all, a social-history programme cunningly disguised as celebrity biography, and the only real point of the latter is to sugar coat the more interesting bits of the former with a gloss of intimate connection. A documentary about slum conditions in Dublin in 1910 wouldn't stand much chance of a 9pm slot on BBC One. But attach it to that fat, mouthy bloke off Radio One's breakfast show and you're home and dry.

At the beginning Moyles confessed that he was hoping to discover more about his Irish roots. His name, he had always believed, was the Gaelic for "soldier", and though someone had already disabused him of this notion he didn't yet know what the real explanation was. "Flower arranger?... not so cool," he speculated, though he probably would have settled for that when he found out its actual origin, which was something like "bald monk servant". "My surname is bald?," he said incredulously to the researcher, "As in slap-head? As in no hair? This trip gets better and better." His grandmother – he'd already discovered – had survived a childhood in a Dublin slum, where she shared a house with five other families and an outhouse with even more. Her own mother and father had died early, in her mother's case shortly after leaving the Dublin workhouse to which she'd been admitted with TB. On his father's side he discovered a tale that brought to mind that old sketch about competitive misery. Five families in one house? You were lucky! What was recorded in the registers here was an infant mortality so grim that his great grandmother had raised only five of the 15 children she'd given birth to.

Moyles did find a soldier in the family – his great-grandfather James, whose experiences lit up another curious footnote in British history – the eager readiness with which Irish nationalists signed up to fight in the First World War, convinced that helping the Empire to win the war would be rewarded with an early release from its grip. James had trained nationalist volunteers before the war, but ended up shortly after it broke out on the Ypres Salient, facing repeated assaults by German troops. They'd even managed to find the very field in which he'd been killed and a newspaper account of his death: "He peeped over the trench and fell back quite dead... a bullet had cut clean through his forehead. He was one of the pleasantest men in the trench". His great grandson – generously paid for his ability to witter on without ceasing – was temporarily lost for words, which was a mercy frankly. Choked inarticulacy seemed a better tribute than the chatty kind.

Wildest Dreams is the result of a breeding experiment – the BBC's Entertainment and Natural History Departments having been persuaded to copulate and produce a reality show in which eight wildlife enthusiasts compete for a potential job as a wildlife cameraman in the Natural History Unit.

It seems a very peculiar way to maintain that department's global reputation for excellence, to me – given that none of these people were qualified by anything other than eagerness and could well have been plucked at random from a passing bus. They are continually briefed on the hazardous unreliability of wild animals ("Don't run... Think about this... Out here food runs") and exposed to the ardours of life in the bush, which in this case included a Kalahari flash food washing them out of their tents at four in the morning. They also get ticked off a lot by their mentors whenever they take an unnecessary risk, which seems a bit rich frankly given that every risk they encounter could have been avoided by not commissioning the programme in the first place.

I assume there must have been a meeting at some point at which "What if a licence payer gets eaten by a lion?" figured on the agenda, but fortunately it didn't happen this time round. Nick Knowles presents, with the assistance of a sizeable repertoire of clichés. "This is Kate," he said, introducing one expert, "What she doesn't know about elephants isn't worth knowing." Peculiarly irritating that one, since if it was true she would rather be wasting her time out in the Kalahari trying to find out more.