Splitting hares is no easy task

THE mad March hare season has arrived. Courtship for Ireland’s fastest mammal, the real ‘Easter bunny’, is a frantic business. Driven by the scent of females in heat, males chase prospective partners who fob them off in dramatic boxing matches.

Would-be suitors jostle and kick each other; only the fittest manage to pass their genes to the next generation. For the losers, discretion is the better part of valour.

Humans ovulate ‘spontaneously’. Eggs are released randomly, a wasteful process; only one in several dozen is ever fertilised. With hares, ovulation is ‘induced’; copulation triggers the release of an egg, a more efficient system. There may be up to four leverets in a litter, not all necessarily from the same father, and a pregnant doe can conceive again before her babies are born.

The geneticists think that the Irish hare became a distinct sub-species between thirty and sixty thousand years ago. How it managed to get here is a matter of speculation but it did so under its own steam. The brown hare, native to mainland Europe, was introduced to several Irish counties in the 19th century. With ears slightly longer than the head, it appeared on the old three-penny bit. According to researchers at Queen’s University Belfast, browns from Britain were released here on 14 occasions between 1848 and 1900.

Elsewhere in Europe, introduced hares ousted their native cousins, forcing them into the mountains, in a hare equivalent of ‘to hell or to Connaught’. The aliens failed to prosper here, however. Ireland is the only country where the native hare is still king from sea level to the hills. As with its human equivalent in Tudor times, only in the North was the brown hare plantation successful; browns are more numerous than native hares in parts of mid-Ulster. The presence of two closely related species, side by side, raises intriguing questions.

Interbreeding between brown and mountain hares has been recorded in Scandinavia. Do such unions occur here and, if so, what effect do they have on the native population? To answer these questions, the Queens researchers used an unlikely resource — road kills. They collected carcasses of hares struck by vehicles and extracted DNA from them.

Between 2002 and 2008, 33 specimens were examined. Seventeen of the victims turned out to be pure Irish hares. Six were browns. Four others could not be identified but the remaining six were hybrids. Mixed unions, therefore, seem to be common among hares in Ireland.

Five of the hybrids had brown hare fathers. This is only to be expected; the brown is reputed to be more athletic than its native cousin, which is why coursing enthusiasts introduced it. In the vigorous courtship rituals, therefore, it would tend to out-perform the natives and obtain more matings.

Considering our own ancient history, the interbreeding of hares is hardly surprising. When our African ancestors arrived in Europe over 40,000 years ago, they encountered Neanderthals, hominids about as closely related to them as Irish and brown hares are to each other.

It was thought, until recently, that our forebears shunned their stocky big- nosed cousins at mating time but recent DNA analysis shows that some interbreeding did occur. Each of us modern humans has some Neanderthal ‘blood’ in the veins. These original Europeans, therefore, did not die out completely; their line, to some extent, was absorbed into ours.

Will the same eventually happen to Ulster’s minority hare population? Browns were released in Dublin, Cork and Donegal over a century ago. Despite occasional claims of sightings, these introductions failed. Did the browns die out because conditions here did not suit them or were they absorbed into the native hare population through inbreeding? An analysis of hare DNA from these counties might answer this question. But there’s another mystery: how did the brown hare manage to hold its own in Ulster, when it failed to do so everywhere else?

*Verification of hybridisation between introduced European brown hares and native Irish hares. Maria Hughes, Neil Reid, Ian Montgomery & Paulo Prodöhl. Quercus, Northern Ireland Environment Agency.


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